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PA Hiking Trails


Website Est. 2005


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GPS Technology

This website was created and is maintained by an educator that is dedicated to delivering..
MAPS, GPS Data and DETAIL about PA Trails like no other!

As I complete pages, the site pages will be updated. Most pages will be broken until the page is complete.
After the migration is complete both URL's will be directed to the new layout. Enjoy!
Feedback is very much appreciated! You can contact the site at georflf@comcast.net or click the feedback link.

Pennsylvania and its wilderness / water supply is in danger, because of the natural gas industry.
Please take action and educate yourself on this destructive process of natural gas extraction known as hydraulicfracturing.
Join the RDA.org (its free!) & the Sierra Club (or just take action, its easy!)
Contact your legislatures & senators to enforce protective law for PA.
Please visit my Marcellus Shale page to learn more about the DANGER Pennsylvania is in.




Note: Welcome to the new
PAHikingTrails.com!!!
I hope you enjoy it.
Currently the site is not complete.
Look for the data on:


www.georflf.com


This is a great place to start if you would like to learn about.
Navigation & GPS Technology!


Page Table of Contents

What is GPS?
Three vital components to GPS operations
GPS Satellite Information
What will interfere with GPS accuracy?
What is Differential GPS?
What is WAAS?
     Map of the 3 WAAS References Stations near PA
     Did other countries create their own GPS systems?
     Will my receiver be able to use their GPS?
Google Earth Plug-in

Global Grid Systems
     Latitude & Longitude (U.S. Version)
        Latitude
        Longitude
        Basic Latitude & Longitude Measurements
        Latitude & Longitude Coordinate Formats
        Latitude & Longitude Coordinate Examples in..
           "National Geographic TOPO!" Software
        Latitude & Longitude Coordinate Examples when..
           Using Garmin's "GPSMap 60CSx"
     Universal Transverse Mercator [UTM] (The rest of the world's versions)
          Easting
          Northing
          UTM Coordinate Examples in..
              "National Geographic TOPO!" Software
          UTM Coordinate Examples in..
             Garmin's "GPSMap 60CSx"
          How do I Measure or Calculate..
             Coordinate distance using UTM?
          UTM Grid Zones Chart

      Military Grid Reference System (MGRS)     
      Universal Polar Stereographic Grid (UPSG)
      Maidenhead Grid
How do I know which "datum" & format my map or GPS is in?
     Cammal, PA Quad displayed with UTM and Lat & Long Reference Lines
Working with & converting Degrees, Minutes, Seconds & Mils
     Minutes & Seconds
     Degrees, Minutes & Seconds
     Converting Decimal Degrees to Decimal Degrees & Minutes
     Converting Decimal Degrees to Degrees, Minutes & Seconds
     What is the Opposing Bearing?
     What is a "Mil"? How does it relate to Navigation?
     Converting Degrees to Mils
     Converting Mils to Degrees
     A few equivalent examples..
Conversion Charts
     Basic Conversions
     USGS Map Scale Conversions
     Latitude & Longitude Distance Conversion Chart
     Decimal Miles to Kilometer, Miles, Meters, Yards and Feet Conversion Chart
Reading Distance on a Paper Map
What is Declination? How Does It Relate to Me?
Vital Things to Take with You Out on the Trail!
Useful Terms
     A-H
     I-P
     Q-Z
Useful Grid System Links

* Click on any of the links to be taken directly to that piece of information



What is GPS?

GPS stands for Global Positioning System. The original name of this system was called NAVSTAR, which is the acronym for: NAVigation Satellite Timing & Ranging. GPS is a worldwide navigation system (developed by the U.S. D.o.D originally for military purposes) that consists roughly of 28 satellites (4 extra, in case one fails) that orbit the earth, along with their corresponding receivers on land. The satellites orbit the earths about 12,500 miles above the earth surface making two complete orbits every 24 hours in a certain spherical pattern at about 7,000 mph!

Each GPS satellite is powered by solar energy with battery backup for events like solar eclipses. The first satellite was launched in 1978 and the complete 24-satellite constellation was not finished until 1994. GPS was opened to the pubic for use in the 1980's, but Selective Availability or SA made it extremely inaccurate for civilian use. SA was intentional data error enforced by the U.S. Gov't for security purposes. SA was later removed in May of 2000.

The GPS satellites continuously transmit data through digital radio signals that contain information about satellite location & time. With this information the earth bound receiver (GPS Unit) can calculate various data such as: location, speed, altitude, etc.

Three satellites are needed to calculate a 2D fix/location (latitude & longitude) called trilateration (method for determining the intersecting point of three or more spherical surfaces), four satellites are needed to include altitude and is known as a 3D fix. Five or more satellites locked in by the receiver helps to increase accuracy. Many GPS units are capable of receiving data from 12 satellites at once. Remember without a GPS Unit the GPS navigation system is useless to you.

Parallel multi-channel design of GPS receivers have allowed them to be very accurate. Additional strengths added to GPS units are stronger processors, electronic downloadable maps & the new SiRF chip. These vital additions have allowed GPS receivers to complete the intrinsic calculations very quickly.




Three Vital Components to GPS Operations

  1. Space
  2. Ground Control
  3. Users


GPS Satellite Information     (24 active, 4 inactive)

  • Transmits Radio signals at:
    • 1227.6 mhz (L2) - carries the CA, P code & nav. message
    • 1575.42 mhz (L1) - carries the P code only
      • at about the speed of light!!
GPS Satellite Orbit around Earth



What Will Interfere with GPS Accuracy?

  1. Ionospheric Inference
    • Slows the GPS transmissions through the atmosphere
    • Decreases accuracy by 5-10 meters
    • WAAS improves this interference
      • New GPSr compensations & calculations for the average delay through the atmospheric zones

  2. Satellite Geometry
    • Refers to the satellite position in the sky
      • Ideally one (1) satellite directly overhead, with three (3) other satellites spaced evenly across the sky

  3. Reflected & Multi-path Signals

  4. Receiver Clock Error (ephemeric error)
    • The receivers clock is not as accurate as the atomic clocks onboard the satellites, there is a slight error that occurs here

  5. Orbital Error (ephemeris error)
    • This is inaccuracies of the satellites reported locations

  6. The Number of Visible Satellites in the Sky
    • The more the better
    • Mostly inoperable when indoors (SiRF improves this, along with high-sensitivity receivers), underwater & underground or within tunnels

  7. Satellite Geometry / Shading
    • Is the relative position of the satellites at any given time
    • Wide angles relative to each other are the best
    • Poor geometry is displayed when the satellites are either in a line or in a tight group

  8. Intentional Degration of the Satellite Signal
    • Selective Availability (SA), is intentional detration of the signal imposed by the United States Department of Defense (DoD)
      • Setup to prevent US enemies from using the accurate GPS signals
      • It was turned off in May of 2000



What is Differential GPS?

Improves GPSr accuracy to within 1 in. (2 mm). DGPS uses the difference between two measurements to improve GPS position and was put into operation by the U.S. Coast Guard. There are currently 60+ land based sites in the U.S. and it's provinces. DGPS is highly accurate for navigational purposes, but would be too costly, heavy and bulky for the consumer looking to use this technology out in the wilderness. Why? in order to use DGPS you must have an additional antenna and a DGPS unit, WAAS is more convenient to the outdoor enthusiast (WAAS is simply a form of DGPS)

DGPS does come in handy for other uses like: dam monitoring, the precise accurately of this system is an excellent way to control water levels and fill rates below the failure point of the dam for flood control.

Two Methods Used By DGPS To Increase Position Calculations
  1. Real-time Corrections: Corrections made while moving. WAAS is based off real-time corrections.
    • Real-time corrections made by DGPS works by using the precise coordinates of its land based receiver. These sites are located along the East & West Coast, including central U.S. and have been accurately surveyed. The DGPS site intercepts the position calculated by the GPSr (intentionally) and compares it to its known exact location. With this information at hand, the DGPS site calculates the GPSr error and corrects it. Once the DGPS land-based site does this it, it sends the corrections to the receiver.
    • The use of DGPS is generally accurate over a limited range of 170 miles (274 km). So it's important that you know the location of the land-based stations to avoid unwanted battery usage. But, DGPS is not usable if your receiver does not accept the Loran-C frequency that is in the RTCM format

  2. Post-processed Corrections: Corrections made after the trip is over. Obviously, not practical for use in the field.

Map of the 3 WAAS References Stations near PA


View WAAS Reference Stations near PA in a larger map

What is WAAS?

WAASAn acronym for Wide Area Augmentation System. This is another U.S. developed navigational system (primary purpose was/is for civil aviation) that further enhances GPS accuracy by correcting minutely flawed data caused by atmospheric disturbance, timing and satellite orbit error.

WAAS is a form of DGPS that is very similar in the sense that it uses corrected data to further improve GPS accuracy, but does this in a different way. In WAAS, land-based stations (located at various points all across the U.S.) calculate any GPS satellite error at any time. The corrected data is up-linked from the land-based stations to the four visible WAAS satellites (#35, 38, 47 & 48) located along the equator at opposite ends of the United States. The WAAS satellites then beam the corrected data all across the continental U.S. & Alaska (soon Hawaii & Canada) where WAAS capable/enabled units can use the corrected data to further enhance the receivers true location. Garmin units display WAAS corrected data with a "D" within the satellite bar. In September of 2002, WAAS testing confirmed accuracy performances to 1-2 meters horizontally and 2-3 meters vertically throughout most of the continental U.S. and parts of Alaska.

For some users that have an obstructed view of the horizon due to mountains, trees, buildings, etc. it is not necessary to enable WAAS on your GPS unit, because the unit can not see the satellites so therefore, it can not communicate with the satellite to correct the data. But with today's technological changes, this may not be the case in the near future.

WAAS is a form of DGPS that is very similar in the sense that it uses corrected data to further improve GPS accuracy, but does this in a different way. In WAAS, land-based stations (located at various points all across the U.S.) calculate any GPS satellite error at any time. The corrected data is up-linked from the land-based stations to two WAAS satellites (#35 & #XX) located along the equator at opposite ends of the United States. The WAAS satellites then beam the corrected data all across the continental U.S. & Alaska (soon Hawaii & Canada) where WAAS capable/enabled units can use the corrected data to further enhance the receivers true location. In September of 2002, WAAS testing confirmed accuracy performances to 1-2 meters horizontally and 2-3 meters vertically throughout most of the continental U.S. and parts of Alaska.



Did Other Countries Create Their Own GPS Systems?GPS Accuracy

YES.
European System: EGNOS (Euro Geostationary Navigation Overlay Service)
Russian System: GLONASS (Global'naya Navigatsionnaya Sputnkovaya Sistema)
Japanese System: MSAS (Multi-Functional Satellite Augmentation System)



Will My Receiver Be able to Use Their GPS?

From my knowledge, the only one compatible is EGNOS. I suggest further research to confirm my findings.




Google Earth Screenshot

Go to Google Earth Program



Global Grid System

Can be defined as the horizontal & vertical lines on a map or globe that fix a position. Many grid systems have been created over the course of time by all different countries. The two most popular U.S. global grid systems are latitude & longitude (in three styles) and Universal Transverse Mercator (UTM).

Global View of Latitude & Longitude Lines



Latitude & Longitude

A spherical coordinate system (global grid system) where the lines of latitude and longitude form an imaginary grid system over the globe. This system is used for navigational purposes on land, sea & air. You probably learned about this grid system in school.



Latitude     Latitude Lines on a Globe



Longitude     Lines of Longitude on a Glove



Basic Latitude & Longitude Measurements



Latitude & Longitude Coordinate Formats

*The coordinates above are for the Ganaga Falls (100'+) located in Ricketts Glenn State Park off Rt.118



Latitude & Longitude Coordinate Examples in "National Geographic TOPO!" Software

Ex1. 41o26'38" N   76o40'43" W   in Degrees, Minutes & Seconds
Ex2. 41o26.626' N   76o40.713' W   in Degrees & Decimal Minutes
Ex3. 41.44377o N   76.67855o W   in Decimal Degrees



Latitude & Longitude Coordinate Examples when using Garmin's "GPSMap 60CSx"

Ex1. 41o25'49.1" N   76o40'14.0" W   in Degrees, Minutes & Seconds
Ex2. 41o25.826' N   76o40.234' W   in Degrees & Decimal Minutes
Ex3. 41.43043o N   76.67056o W   in Decimal Degrees


*The above coordinates are for “Dry Run Waterfalls Parking Area" located off Dry Run Road, which is accessible off Rt.87. The Dry Run Waterfalls are a very pretty waterfall that is about 20' high.



Universal Transverse Mercator (UTM)

UTM Global Grid System


A global grid system that splits the earth into 60 zones that run east to west, each zone of which is 6o wide for two reasons; reduced distortion when converted from a spherical globe to a flat paper map & the ease of use on a paper map with northing & easting values being measured in meters. This system starts at the zone meridian (180o aka the International Dateline, when referencing to the latitude & longitude system) and uses letters of the alphabet along with easting & northing values.

UTM maps do not cover areas above 84oN. latitude & 80oS. latitude. The remaining degrees above & below these lines are drawn using Universal Polar Stereographic Grid (UPS). This grid system will be talked about at a later time.

Definition #2: UTM stands for Universal Transverse Mercator. This system is popular for use on land. Unlike lat. & long., which projects imaginary grid lines on the globe. UTM projects section of the globe on a flat surface, like a map. Again there are 60 sections or zones in the UTM system that cover 6o each. This type of grid system starts with section 1 at 180o - 174o, continuing west to zone 60. Two other elements describe this system in greater detail; they are easting and northing values. Easting & northing values measure how far in meters, within the zone the reference point is.


UTM World Zones


Easting

Northing



UTM Coordinate Examples in "National Geographic TOPO!" Software

Ex. 18T 295718mE 4621044mN

* The above example is coordinates in UTM format for "Owassee Rapids" on the Pine Creek. This rapids is a Class II rapid on a 6 scale system

* Notice how NG TOPO combines the zone letter & splits the easting & northing values. Also note how the numbers are all the same size



UTM Coordinate Examples in Garmin's "GPSMap 60CSx"

Ex. 18 T 363327 4591410

* The above example is coordinates in UTM format for “Split Rock" on the Loyalsock Trail. This landmark is a cool rock that split over time creating crevasses between the rock



How Do I Measure or Calculate Coordinate Distance Using UTM?

It's quite simple actually. If you remember each UTM grid line is divided by 1000 meters, with this in mind, it's real simple to figure out a waypoint coordinates.

Ex. Someone has told you that there is a really cool vista near Blackwell off the MST known as the “Materhorn." They show you its general location on the map, but neither of you know the coordinates and you would like to plot it on your map & in your GPS.

To figure this out, take your UTM legend that shows the map scale and measure from one of the main UTM easting lines, either 302000m.E. or 303000m.E.. If you use 302000m.E., then you add those meters to the last three 0's. If you use 303000m.E., then you subtract those meters to the last three 0's and vice versa for the northing lines.

Easting line: 302000m.E. + 129 (measured meters) = 302129m.E. (Easting value)

Northing line: 4602000m.E. + 763 (measured meters) = 4602763m.E. (Northing value)

Coordinates: 302129m.E. 4602763m.E.


The Universe Transverse Mercator Grid for the United States Determining a UTM Grid Value for a Map Point
UTM Grid Values for the US Finding the UTM Grid Points


UTM Grid Zone Chart

Zone Degree   Degree   Zone Degree   Degree   Zone Degree   Degree   Zone Degree   Degree
1 180 oW - 174 oW 16 90 oW - 84 oW 31 0 oE - 6 oE 46 90 oE - 96 oE
2 174 oW - 168 oW 17 84 oW - 78 oW 32 6 oE - 12 oE 47 96 oE - 102 oE
3 168 oW - 162 oW 18 78 oW - 72 oW 33 12 oE - 18 oE 48 102 oE - 108 oE
4 162 oW - 156 oW 19 72 oW - 66 oW 34 18 oE - 24 oE 49 108 oE - 114 oE
5 156 oW - 150 oW 20 66 oW - 60 oW 35 24 oE - 30 oE 50 114 oE - 120 oE
6 150 oW - 144 oW 21 60 oW - 54 oW 36 30 oE - 36 oE 51 120 oE - 126 oE
7 144 oW - 138 oW 22 54 oW - 48 oW 37 36 oE - 42 oE 52 126 oE - 132 oE
8 138 oW - 132 oW 23 48 oW - 42 oW 38 42 oE - 48 oE 53 132 oE - 138 oE
9 132 oW - 126 oW 24 42 oW - 36 oW 39 48 oE - 54 oE 54 138 oE - 144 oE
10 126 oW - 120 oW 25 36 oW - 30 oW 40 54 oE - 60 oE 55 144 oE - 150 oE
11 120 oW - 114 oW 26 30 oW - 24 oW 41 60 oE - 66 oE 56 150 oE - 156 oE
12 114 oW - 108 oW 27 24 oW - 18 oW 42 66 oE - 72 oE 57 156 oE - 162 oE
13 108 oW - 102 oW 28 18 oW - 12 oW 43 72 oE - 78 oE 58 162 oE - 168 oE
14 102 oW - 96 oW 29 12 oW - 6 oW 44 78 oE - 84 oE 59 168 oE - 174 oE
15 96 oW - 90 oW   30 6 oW - 0 oW   45 84 oE - 90 oE   60 174 oE - 180 oE

UTM Grid System Excel Document



Military Grid Reference System (MGRS)

MGRS Grid System


The MGRS is the global grid system designed by the U.S. Military, used by the U.S. Military and NATO Forces. This system is very similar to the UTM grid system, except that the majority of the numbers (first two) are replaced with letters & the letters run horizontally instead of vertically.

Example Coordinates in different formats

  • UTM: 12 S 0501788m.E.     3690619m.N.
  • MGRS: 12 S WB 01788,     90619
  • GPSr: 12 SWB 0178890619

The MGRS system divides the globe into 8o sections instead of 6o sections like the UTM grid system. So therefore, there are 19 sections, each covering 8o that run horizontally, except for the northern most section which covers 10o. The letters start from the southern most hemisphere using the letters C, D, E, F, G, H, J, K, L, M, (all in southern hemisphere) N, P, Q, R, S, T, U, V, W, X (all in the northern hemisphere). The southern most section of the MGRS system is assigned letter C & the northern most grid section is letter X. This grid system is not popular among outdoor enthusiast, because USGS maps do not display this grid on their maps.



Converting UTM Easting & Northing Numbers to MGRS



Universal Polar Stereographic Grid (UPSG)

UPS Grid System

A special uniform grid system developed for use in the Arctic & Antarctic regions of the world. The UTM grid system can be used for these regions also, but the zones are very narrow and confusing to read if using UTM so therefore the UPS was created. UPS does share some similarities with the UTM system in that they both have eastings and northings and each is 1000 meters (.62 miles) in size.



Ordinance Survey Great Britain (OSGB)

Ordnance Survey Grid System

This is the national grid system for Great Britain and Great Britain only. This grid system is separated into square sections each 100km in size (62.1 miles). Each grid is assigned a double letter that is 7 grids wide by 13 grids high. This grid system is also similar to the UTM system in that: it has easting and northings, its unit of measure is in metric, the last three numbers a grid coordinate represent meters and its easy figure out distance between two coordinates within the same grid.

 

I will not go into great detail for the MGRS, UPS, OGSB, MGS grid systems. The two primary navigational systems used by the United States is the UTM and Latitude & Longitude. There are a lot of great resources out on the Internet if you would like to learn more about these grid systems.

 




Maidenhead Grid

Maidenhead Grid System Map


This grid system was developed and operated by amateur radio operators. It divides the world into rectangular grids each 20o of longitude and 10o of latitude for a total of 18 grids wide (A-R) running east to west and 15 grids high (D-R) running south to north. Each grid is identified by two letters and are further subdivided by 2o by 1o and labeled with two numbers (00-99). This grid system subdivides one more time; each sub-area is 5' of longitude by 2.5' of latitude and is labeled with the letters AA-XX.

Ex. EM18BX

FYI: Grid letters above and to the right of the letter “J" are located in the northern hemisphere and in the eastern hemisphere.



MGRS Subdivision's




How Do I Know Which Datum & Format My Map or GPS is in?

To figure out how your map has been setup look over the legend and look to the edges of the map. The USGS Topo! software tells you the datum used in the upper right & lower right-hand corners. It can also generate maps in four formats (3 lat. & long. & UTM). The format markings are along the outer edges of the map & would contain the coordinates.

The USGS maps you purchase at outfitters are 7.5' topographic maps. You will find (9) 2.5' blocks on each map. 7.5' is the distance it covers in both directions using the latitude & longitude grid system. It will also contain the UTM grid system with markings every 1000 meters.

* The map below would contain UTM marks from: 4584 – 4597 for northing (south to north) & 291 – 301 for eastings.




Northern Coordinates: Northwest Corner USGS 24K Topo Map Northeast Corner
  Lat. & Long.: 41o30'00" N.   77o30'00" W. Cammal, PA Quadrangle

41o30'00" N.   77o22'30" W.

              UTM:         4597 N. 291 E.
USGS 24K Topo Map - Cammal, PA Quad
        4597 N. 301 E.
   
   
   
   
   
Midpoint of Map: Lat. & Long.: 41o26'15"   N.77o26'15" W.  
   
   
   
   
   
   
   
Southern Coordinates: Southwest Corner Southeast Corner
Lat. & Long.: 41o22'30" N.   77o30'00" W. 41o22'30" N.   77o22'30" W.
            UTM:         4584 N. 291 E.         4584 N. 301 E.




USGS 24K TOPO Cammal Quad labeled in two different formats..
         
UTM by 1000m intervals 
USGS UTM - Cammal, PA Quad
and Latitude & Longitude 
USGS Lat. & Long - Cammal Quad  * (Large Files! 3.5MB each)


Note: When using the National Geographic TOPO! software set the grid markings to:



Working with & Converting Degrees, Minutes, Seconds & Mils


Working with.. Minutes & Seconds     (XX' XX")



Working with.. Degrees, Minutes & Seconds     (XXo XX' XX")



Converting Decimal Degrees to.. Decimal Degrees & Minutes     (XX.XXXo to.. XXoXX')



Converting Decimal Degrees to.. Degrees, Minutes & Seconds     (XX.XXXo to.. XXoXX'XX")



What is the Opposing Bearing?



What is a Mil?.. How does it relate to Navigation?



Converting Degrees to Mils



Converting Mils to Degrees



A Few Equivalent Examples



Conversion Charts

Basic Conversions

  • inch = in.
  • feet = ft.
  • yard = yd.
  • mile = mi.
  • ounce = oz.
  • pound = lb.
  • millimeter = mm
  • centimeter = cm
  • meter = m
  • kilometer = km
  • 12 in. = 1 ft.
  • 3 ft. = 1 yd.
  • 1 yd. = .9144m
  • 5,280 ft. = 1mi.
  • 1mi. = 1.609km
  • 2.54 cm = 1 in.
  • 39.37 in. = 1 m
  • 3.28 ft. = 1 m
  • 1000 m = 1 km
  • 1 km = .62 mi.
  • .01 mi = 52.8 ft.
  • .06 mi. = 100 yards roughly



USGS Map Scale Conversions Chart

* Each inch of map represents the numbers below according to the map scale they were printed in
 
General USGS Map Scales
Scale
Inches
ft. p/in.
yds. p/in.
mi. p/in.
1:500
500,000
41,666.67
13,888.89
7.89
 
1:100
100,000
8,333.33
2,777.78
1.58
 
1:24
24,000
2,000.00
666.67
0.38
 
 
* USGS 7.5min maps are generally 1:24th scale
 
National Geographic TOPO! Scales
Scale
Inches
ft. p/in.
yds. p/in.
mi. p/in.
 
1:4000000
4,000,000
333,333.33
111,111.11
63.13
 
1:865000
865,000
72,083.33
24,027.78
13.65
 
1:327360
327,360
27,280.00
9,093.33
5.17
 
1:50000
50,000
4,166.67
1,388.89
0.79
 
1:15375
15,375
1,281.25
427.08
0.24
 
 
* Nat. Geo's highest scaled Topo is equivalent to USGS 1:24th scale

Map Scale Conversion Excel Document

* measurements were calculated and rounded to the nearest 100th, so they are not exact, but very close.



Latitude & Longitude Distance Conversion Chart

1 degree 69.05   miles  
  5,280.00   feet to 1 mile  
  364,584.00   feet in 1 degree  
  121,528.00   yards in 1 degree  
  100,000.00   decimal degrees to 1 degree  
36,4584 3.65   .000001 decimal degrees in feet  
12,1528 1.22   .000001 decimal degrees in yards  
         
1 minute 1.15   miles to 1' minute 60 min. to 1 degree
  5,280.00   feet to 1 mile  
  6,072.00   feet in 1 minute  
  2,024.00   yards in 1 minute  
  1,000.00   decimal minutes to 1 minute  
6,072 6.07   .001 decimal minutes in feet  
2,024 2.02   .001 decimal minutes in yards  
         
1 second 0.01917   miles to 1" second 60 sec. to 1 min.
  5,280.00   feet to 1 mile  
  1,760.00   yards to 1 mile  
6,072 101.20000   feet to 1 second  
2,024 33.73333   yards to 1 second  
Latitude & Longitude Globe

Latitude & Longitude Distance Conversion Excel Document



Decimal Miles to KM, Mi., M, Yds. & Ft. Conversion Chart

.06 miles = 317ft. or 105yds.
.1 miles = 528ft. or 176yds.
.2 miles = 1,056ft. 352yds.
.25 miles = 1,320ft. or 440yds.
.3 miles = 1,584ft. or 528yds.
.4 miles = 2,112ft. or 704yds.
.5 miles = 2,640ft. or 880yds.

.5 miles = 2,640ft. or 880yds.
.6 miles = 3,168ft. or 1,056yds.
.7 miles = 3,696ft. or 1,232yds.
.75 miles = 3,960ft. or 1,320yds.
.8 miles = 4,224ft. or 1,408yds.
.9 miles = 4,752ft. or 1,584yds.
1 mile = 5,280ft. or 1,760yds.
Kilometers
Meters
Feet
Yards
Decimal Miles
0.00 km 0.00 m 0.00 ft 0.00 yds 0 mi
0.02 km 16.10 m 52.80 ft 17.60 yds 0.01 mi
0.03 km 32.20 m 105.60 ft 35.20 yds 0.02 mi
0.05 km 48.29 m 158.40 ft 52.80 yds 0.03 mi
0.06 km 64.39 m 211.20 ft 70.40 yds 0.04 mi
0.08 km 80.49 m 264.00 ft 88.00 yds 0.05 mi
0.10 km 96.59 m 316.80 ft 105.60 yds 0.06 mi
0.11 km 112.68 m 369.60 ft 123.20 yds 0.07 mi
0.13 km 128.78 m 422.40 ft 140.80 yds 0.08 mi
0.14 km 144.88 m 475.20 ft 158.40 yds 0.09 mi
0.16 km 160.98 m 528.00 ft 176.00 yds 0.1 mi
0.18 km 177.07 m 580.80 ft 193.60 yds 0.11 mi
0.19 km 193.17 m 633.60 ft 211.20 yds 0.12 mi
0.21 km 209.27 m 686.40 ft 228.80 yds 0.13 mi
0.23 km 225.37 m 739.20 ft 246.40 yds 0.14 mi
0.24 km 241.46 m 792.00 ft 264.00 yds 0.15 mi
0.26 km 257.56 m 844.80 ft 281.60 yds 0.16 mi
0.27 km 273.66 m 897.60 ft 299.20 yds 0.17 mi
0.29 km 289.76 m 950.40 ft 316.80 yds 0.18 mi
0.31 km 305.85 m 1,003.20 ft 334.40 yds 0.19 mi
0.32 km 321.95 m 1,056.00 ft 352.00 yds 0.2 mi
0.34 km 338.05 m 1,108.80 ft 369.60 yds 0.21 mi
0.35 km 354.15 m 1,161.60 ft 387.20 yds 0.22 mi
0.37 km 370.24 m 1,214.40 ft 404.80 yds 0.23 mi
0.39 km 386.34 m 1,267.20 ft 422.40 yds 0.24 mi
0.40 km 402.44 m 1,320.00 ft 440.00 yds 0.25 mi
0.42 km 418.54 m 1,372.80 ft 457.60 yds 0.26 mi
0.43 km 434.63 m 1,425.60 ft 475.20 yds 0.27 mi
0.45 km 450.73 m 1,478.40 ft 492.80 yds 0.28 mi
0.47 km 466.83 m 1,531.20 ft 510.40 yds 0.29 mi
0.48 km 482.93 m 1,584.00 ft 528.00 yds 0.3 mi
0.50 km 499.02 m 1,636.80 ft 545.60 yds 0.31 mi
0.52 km 515.12 m 1,689.60 ft 563.20 yds 0.32 mi
0.53 km 531.22 m 1,742.40 ft 580.80 yds 0.33 mi
0.55 km 547.32 m 1,795.20 ft 598.40 yds 0.34 mi
0.56 km 563.41 m 1,848.00 ft 616.00 yds 0.35 mi
0.58 km 579.51 m 1,900.80 ft 633.60 yds 0.36 mi
0.60 km 595.61 m 1,953.60 ft 651.20 yds 0.37 mi
0.61 km 611.71 m 2,006.40 ft 668.80 yds 0.38 mi
0.63 km 627.80 m 2,059.20 ft 686.40 yds 0.39 mi
0.64 km 643.90 m 2,112.00 ft 704.00 yds 0.4 mi
0.66 km 660.00 m 2,164.80 ft 721.60 yds 0.41 mi
0.68 km 676.10 m 2,217.60 ft 739.20 yds 0.42 mi
0.69 km 692.20 m 2,270.40 ft 756.80 yds 0.43 mi
0.71 km 708.29 m 2,323.20 ft 774.40 yds 0.44 mi
0.72 km 724.39 m 2,376.00 ft 792.00 yds 0.45 mi
0.74 km 740.49 m 2,428.80 ft 809.60 yds 0.46 mi
0.76 km 756.59 m 2,481.60 ft 827.20 yds 0.47 mi
0.77 km 772.68 m 2,534.40 ft 844.80 yds 0.48 mi
0.79 km 788.78 m 2,587.20 ft 862.40 yds 0.49 mi
0.80 km 804.88 m 2,640.00 ft 880.00 yds 0.5 mi
Kilometers
Meters
Feet
Yards
Decimal Miles
0.80 km 804.88 m 2,640.00 ft 880.00 yds 0.5 mi
0.82 km 820.98 m 2,692.80 ft 897.60 yds 0.51 mi
0.84 km 837.07 m 2,745.60 ft 915.20 yds 0.52 mi
0.85 km 853.17 m 2,798.40 ft 932.80 yds 0.53 mi
0.87 km 869.27 m 2,851.20 ft 950.40 yds 0.54 mi
0.89 km 885.37 m 2,904.00 ft 968.00 yds 0.55 mi
0.90 km 901.46 m 2,956.80 ft 985.60 yds 0.56 mi
0.92 km 917.56 m 3,009.60 ft 1,003.20 yds 0.57 mi
0.93 km 933.66 m 3,062.40 ft 1,020.80 yds 0.58 mi
0.95 km 949.76 m 3,115.20 ft 1,038.40 yds 0.59 mi
0.97 km 965.85 m 3,168.00 ft 1,056.00 yds 0.6 mi
0.98 km 981.95 m 3,220.80 ft 1,073.60 yds 0.61 mi
1.00 km 998.05 m 3,273.60 ft 1,091.20 yds 0.62 mi
1.01 km 1,014.15 m 3,326.40 ft 1,108.80 yds 0.63 mi
1.03 km 1,030.24 m 3,379.20 ft 1,126.40 yds 0.64 mi
1.05 km 1,046.34 m 3,432.00 ft 1,144.00 yds 0.65 mi
1.06 km 1,062.44 m 3,484.80 ft 1,161.60 yds 0.66 mi
1.08 km 1,078.54 m 3,537.60 ft 1,179.20 yds 0.67 mi
1.09 km 1,094.63 m 3,590.40 ft 1,196.80 yds 0.68 mi
1.11 km 1,110.73 m 3,643.20 ft 1,214.40 yds 0.69 mi
1.13 km 1,126.83 m 3,696.00 ft 1,232.00 yds 0.7 mi
1.14 km 1,142.93 m 3,748.80 ft 1,249.60 yds 0.71 mi
1.16 km 1,159.02 m 3,801.60 ft 1,267.20 yds 0.72 mi
1.18 km 1,175.12 m 3,854.40 ft 1,284.80 yds 0.73 mi
1.19 km 1,191.22 m 3,907.20 ft 1,302.40 yds 0.74 mi
1.21 km 1,207.32 m 3,960.00 ft 1,320.00 yds 0.75 mi
1.22 km 1,223.41 m 4,012.80 ft 1,337.60 yds 0.76 mi
1.24 km 1,239.51 m 4,065.60 ft 1,355.20 yds 0.77 mi
1.26 km 1,255.61 m 4,118.40 ft 1,372.80 yds 0.78 mi
1.27 km 1,271.71 m 4,171.20 ft 1,390.40 yds 0.79 mi
1.29 km 1,287.80 m 4,224.00 ft 1,408.00 yds 0.8 mi
1.30 km 1,303.90 m 4,276.80 ft 1,425.60 yds 0.81 mi
1.32 km 1,320.00 m 4,329.60 ft 1,443.20 yds 0.82 mi
1.34 km 1,336.10 m 4,382.40 ft 1,460.80 yds 0.83 mi
1.35 km 1,352.20 m 4,435.20 ft 1,478.40 yds 0.84 mi
1.37 km 1,368.29 m 4,488.00 ft 1,496.00 yds 0.85 mi
1.38 km 1,384.39 m 4,540.80 ft 1,513.60 yds 0.86 mi
1.40 km 1,400.49 m 4,593.60 ft 1,531.20 yds 0.87 mi
1.42 km 1,416.59 m 4,646.40 ft 1,548.80 yds 0.88 mi
1.43 km 1,432.68 m 4,699.20 ft 1,566.40 yds 0.89 mi
1.45 km 1,448.78 m 4,752.00 ft 1,584.00 yds 0.9 mi
1.46 km 1,464.88 m 4,804.80 ft 1,601.60 yds 0.91 mi
1.48 km 1,480.98 m 4,857.60 ft 1,619.20 yds 0.92 mi
1.50 km 1,497.07 m 4,910.40 ft 1,636.80 yds 0.93 mi
1.51 km 1,513.17 m 4,963.20 ft 1,654.40 yds 0.94 mi
1.53 km 1,529.27 m 5,016.00 ft 1,672.00 yds 0.95 mi
1.55 km 1,545.37 m 5,068.80 ft 1,689.60 yds 0.96 mi
1.56 km 1,561.46 m 5,121.60 ft 1,707.20 yds 0.97 mi
1.58 km 1,577.56 m 5,174.40 ft 1,724.80 yds 0.98 mi
1.59 km 1,593.66 m 5,227.20 ft 1,742.40 yds 0.99 mi
1.61 km 1,609.76 m 5,280.00 ft 1,760.00 yds 1.00 mi

1 mile = 63,360 inches
1 mile = 5,280 feet
1 mile = 1,760 yards
1 mile = 2,112 strides (30" avg.)

1 mile = 160,900 centimeters
1 mile = 1,609 meters
1 mile = 1.61 kilometers
1 kilometer = .62 miles

The above chart in an excel document     -    feet to mile chart in excel    -    feet & yards to miles chart in excel    -    feet, yards & km to miles chart in excel

www.onlineconversions.com is a great website that converts just about anything!



Reading Distance on a Paper Map

Can You Read, Make Out and Interpret distance on a Paper Map?

Yes, you can (to a certain extent) do this by knowing the distance between o (degrees), ' (minutes), " (seconds) or UTM's meters, but the best way is:

  1. Use the legend to interpret distance along with some sort of straight edge instrument.
  2. Use a special ruler that is calibrated to read minutes & seconds on a 2.5' x 2.5' grid.
  3. Use the ruler on your compass (make sure the scale on the map & the compass match)!
  4. Draw a finer grid on your map (subdivide the map into smaller grids).
    • Make sure the grid lines are easy to interpret distance measurements and are easy to read.
    • When interpreting distance on a paper map, it takes some knowledge & practice to accurately interpret distance.
      • Latitude distance is consistent.
      • Longitude distance is not! If you remember from my bulleted information about longitude, as you move north or south away from the equator, the distance between grid lines decreases. The only time both latitude & longitude are the same is at the equator.


What is Declination? How Does It Relate to Me?

Declination is the difference between magnetic north (the direction your compass points) and true or grid/map north (the direction the map indicates is north, which is the North Pole). Declination difference will be in degrees and varies depending on what part of the US you live in. The varying degree can be as much as +18o. Here in central Pennsylvania it's oughly 11oW or -11o.

You must know the declination of the area you are in, for example:

* Determining Your Declination – Expressed as either East or West Declination according to your present location of the magnetic North Pole



If your present location is right of the magnetic pole line, it is considered
West Declination. (PA is west declination)

West Declination Symbol on a Map
Example of the west declination symbol on a map.

If your present location is left of the magnetic pole line; it is considered
East Declination. (Midwest to CA is east declination)

East Declination Symbol on a Map
Example of the east declination symbol on a map

Continental Map of US Declination

Click either map to view full size image

Maps courtesy of: National Geophysical Data Center

North America Map of Declination
Continental US in a pdf document for download
North America in a pdf document for download


East is Least, West is Best – Which means you subtract east declinations and add west declinations to your calculations depending on which side of the magnetic pole line you stand on. The examples below show you how do do this.

Example #1

Location:Eastern Pennsylvania
Origin: Doodle Hollow Road
Coordinates: 41o 13' 50" N 74o 53' 31" W (Start)
Destination: Dingmans Falls
Coordinates: 41o 13' 51" N 74o 53' 45" W (Finish)
Estimated Distance: .22 miles
Map Declination: 13oW (according to my map)
Maps Compass Bearing: 93o
Maps Compass Bearing + Declination: 93o + 13oW = 106o (Magnetic North)
Correct Compass Bearing to Waterfalls: 106o (follow compass bearing in this direction to reach the falls in .22 miles)

Example #2

Location: Central Montana
Origin: Neihart, MT
Coordinates: 46o 54' 36" N 110o 43' 52" W (Start)
Destination: Big Baldy Mt. Peak
Coordinates: 46o 57' 05" N 110o 35' 05" W (Finish)
Estimated Distance: 7.18 miles
Map Declination: 13oE (according to my map)
Maps Compass Bearing: 64o
Maps Compass Bearing + Declination: 64o - 13.5oE = 50.5o (Magnetic North)
Correct Compass Bearing to Mt. Peak:50.5o (follow compass bearing in this direction to reach the Mt. Peak in 7.18 miles)

* Most all maps will tell you the declination difference somewhere on the legend, the USGS Topo! software maps declination is located in the lower right corner.
* Declination changes due to the floating magnetic poles. The maps above are current as of 2011.




Vital Things to take with You on the Trail!



Useful Terms

A-H

2D Operating Mode – In GPS terms, it is a two-dimensional fix on a location that only contains a horizontal fix without elevation. A minimum of 3 satellites is required for this operation mode.

3D Operating Mode – In GPS terms, it is a three-dimensional fix on a location that includes both a horizontal fix and elevation. A minimum of 4 satellites is required for this operating mode.

Almanac Data – Information transmitted by the GPS Satellite telling the receiver its current health & orbital status.

Altimeter – An instrument used to determine elevation.

Altitude - The elevation above sea level or above the earth surface.

Atomic Clock – A very precise clock. Each GPS satellite contains many of these clocks. They are extremely accurate, because of the rubidium & cesium components (one-second error per one million years).

Azimuth – Aka bearing, is the compass position between your present position and your destination. It is mostly expressed in degrees (o), but sometimes can be displayed in mils.

Barometer – An instrument used to determine the pressure in the air.

Compass – A navigational instrument used to find direction.

Coordinates - These are numbers and letters that precisely label any and all positions on earth. Every position on earth has a unique coordinate. The displayed coordinate of a position is determines by the grid & datum used.

Coordinate Point – A point associated to a coordinate system in which a coordinate is identified at where the meridian and the parallel intersect.

Coordinated Universal Time (UTC) – This system of time replaced the Greenwich Mean Time (GMT) in 1986 and is now the world standard. This time compensates for the leap year and any changes in the earths rotation.

Course Acquisition Codes (CA code) – The standard code transmitted by GPS Satellites. This transmission code allow users to utilize the global positioning system. The information contained within this code is for civilian use and is accurate to within 10 feet. The best reception I ever had in combination with WAAS was 6 feet!

Data Formats – The way in which the map has been written to calculate distance and the grid system used. There are generally three data formats; each format is best suited to a particular grid system.

  1. Metric: The European & world unit of measurement, Ex. Kilometer, meters
                 Grid System Preference: UTM, UPS, MGRS & OSGB
  2. Nautical: Used on the open waters by sailors & others, this is used in reference to marine charts, Ex. Nautical mile, knots
                 Grid System Preference: Marine Charts, Latitude & Longitude
  3. Statue: The U.S. units of measure, such as: feet, Fahrenheit, miles per hour.
                 Grid System Preference: Latitude & Longitude

Declination – Is the difference between the North Pole and the Magnetic Pole in degrees or mils in reference to your position. Most maps display this in degrees

The United States Department of Defense (DoD) – Maintains and controls the GPS system along with a variety of other duties.

Differential GPS (DGPS) – An extension of the GPS system used by WAAS. This system consists of land-based radio beacons located a various locations across the country (east coast, middle & west coast) that transmits corrected GPS position data. First implemented by the U.S. Coast Guard. DGPS improves GPSr accuracy to within 10 meters, I have experienced an improvement to within 10 feet! DGPS does have the potential to increase positional accuracy to within 1 in. (2 mm)! But not without added equipment & substantial costs; not to mention we civilians do not have access to the P-Code.

Easting – Similar to a northing, except is refers to the distance east or west of a fixed reference point, which is the International Dateline. Again you will see this value used in the UTM, MGRS and others.

Elevation – The distance above or below the mean sea level.

Elevation Profile - Is a cross-section of the trail, route or drawn route that displays the changes in elevation at every point on the trip. This is an invaluable feature provided by topographical software that displays to you how easy or strenuous the hike may be.

Elevation Profile – shows the elevation gain or loss along a trail from a horizontal aspect. This information is very informative when it comes to the amount of time and miles you will hike when planning out a hike or backpacking trip.

Emphemeris Data – Data that is valid for several hours and contains current satellite position and timing information. This emphermeris data is transmitted by the GPS satellite as part of the satellite data message.

Geographic Coordinates – A coordinate values given as latitude and longitude.

GPS – A satellite system used to navigate. This system enables anyone on Earth who owns a GPS receiver to know where they are at any time, no matter what the weather.

GPSr – This is short for the GPS receiver. The GPSr communicates with the satellites to calculate the fixed or moving location of the individual or object that is equipped with the unit.

Grid – The horizontal & vertical lines on a map or globe that fix your position. Many grid systems have been created over the course of time by all different countries. The two most popular U.S. global grid systems are latitude & longitude (in three styles) and Universal Transverse Mercator (UTM).

Grid North – aka True North, both are used interchangeably. This is the direction to the North Pole.


I-P

Ionosphere – A region of the earth's atmosphere 50–250 miles wide (50–400 km) and affects GPS radio waves due to the incoming solar radiation.

L-Band – The radio frequency that carries the L1 & L2 frequency that consists of the all GPS satellite data and operates within the range of 390-1550 Mhz.

Latitude & Longitude – A spherical coordinate system (global grid system) where the lines of latitude and longitude form an imaginary grid system over the globe. This system is used for navigational purposes on land, sea & air. You probably learned about this grid system in school. The UTM systems is based off this system, but instead uses zones (60 of them.)

Latitude – These imaginary lines or degrees (o) run horizontally around the Earth and tell you how far north or south something is from the Equator. The equator line of latitude is 0o. From the Equator there are 90 lines of latitude that extend northward to the North Pole and are followed by the letter N to indicate north. There are also 90 lines of latitude that extend southward to the South Pole and are followed by the letter S to indicate south. Ex. 41oN latitude (indicates line of latitude north of the equator). PA is roughly located within 39oN - 42oN latitude. All lines of latitude are parallel to one another and are known as parallels.

Local Area Augmentation System (LAAS) – A real-time DGPS correction system with a 20-30 mile radius developed by the U.S. Federal Aviation Administration for landing aircraft at small to medium-sized airports. The LAAS system is extremely accurate to within 1 meter on the horizontal and vertical plane.

Longitude – These imaginary lines or degrees (o) run vertically around the Earth and tell you how far east or west something is from the Prime Meridian (Greenwich, England). 0o longitude is located in England. From this line of longitude there are 180 lines or degrees (o) that run east of the Prime Meridian and 180 lines that run west of the Prime Meridian. The International Dateline is the line where the two 180o of longitude meet. The U.S. is located in the western hemisphere and all lines of longitude are followed by a W. Ex. 076oW PA is roughly located within 74oW - 80oW longitude.All lines of longitude are parallel and are known as meridians. Two lines that intersect are perpendicular to one another. Where these two lines cross a reference point or coordinate follows. Coordinates generally list the line of latitude first. Ex. N41 26.987 W76 38.606. This is the coordinate of “Split Rock" located at mile 34.28 on the Loyalsock Trail. N41 represents the line of latitude and the 5digit extension that follows this example stands for, degrees & decimal minutes according to the WGS84 datum. The 4-5digit number added to each degree is the specific or exact location within each degree. These digits are needed because miles of land separate each degree of latitude & longitude. There are basically three global grid systems based off lat. & long. They are: decimal degrees, degrees & decimal minutes or degrees, minutes & seconds.

Magnetic North – The direction in which a compass needle always points. This magnetic pole is located in northern Canada and has a 12o declination to the North Pole in our area of the globe. Most maps are laid out in true (grid) north. (You must know the declination from your location to correctly navigate to your destination with a compass.) Points to the magnetic North Pole, which is located in northern Canada. All compasses made for use in the U.S. point to the magnetic North Pole, not true north. Most papers are laid out in true (grid) north. You must know the declination from your location to correctly navigate to your destination.

Map Datum - All Maps are drawn with respect to a reference point (specific location). This reference point is known as a datum, so therefore datum's are used as a basic of calculating and measuring. Since maps generally only cover a portion of the earth in a larger scale, datum's have been created to pinpoint a certain location. The transition from a global view to a paper map view is where a datum comes in. Similar to the grid system, just on a more precise scale, 100's of map datum's been created by the U.S., and other countries for navigational purposes. The U.S. generally uses the World Geodetic System 1984 (WGS84) or North American Datum 1927 (NAD27).

Map Scale – Maps are scaled out according to a certain measurement. Most maps, especially USGS maps are scaled to 1:500,000, 1:100,000 & 1:24,000. The most popular and most detailed map scale is 1:24,000, which means that for every one inch on the map, it represents 24,000 inches on the ground. Generally the 1:24,000 covers less area on a map than the 1:100,000 and so on.

Meridian – Lines of longitude, a term used in grid systems. Meridians are imaginary lines that run from the North Pole to the South Pole. Each meridian is perpendicular to all circles of latitude at the intersection points.

Metric – The European & world unit of measurement with a base number of ten (10) and a base unit of a meter. Ex. Kilometer (km), meters (m), centimeter (cm), millimeter (mm). Grid System Preference: UTM, UPS, MGRS & OSGB.

Nautical – Used on the open waters by sailors & others. Nautical is referenced to marine charts. Ex. Nautical mile, knots. Grid System Preference: Marine Charts, Latitude & Longitude.

Navigational Message – Information within the GPS satellite signal that contains velocity, time, position.

Navigational Screens – Visual screens or pages that display statistical data about your adventure. Some data on these pages can be changed and some can not.

* Garmin Receivers tend to display 5 or 6 main pages or more (which is up to the user). The 6 basic pages are:

    1. Map Page: displays the map of the area you are in, along with variable data fields.
    2. Compass Page: displays the compass bearing, along with variable data fields.
    3. Trip Computer Page: displays a variety of variable statistical & navigational data used on the expedition.
    4. Satellite Page: displays the satellite locations in the sky, how many your GPSr has locked and the accuracy of the receiver.
    5. Menu Page: displays icons where the user can change preferences and advanced features of the unit.
    6. Altimeter Page: displays altimeter readings or profile & barometric pressure plots, plus more.

Navigational Statistics – Calculated data according to its title. Many GPS receivers are capable of recording or displaying a wide variety of statistical data that you may find useful on your adventure.

* Examples of such data that are seen on the Garmin GPSMAP 60CSx are:

Accuracy of GPS, Bearing, Course, Depth, Distance To Destination, Distance To Next, ETA At Destination, ETA To Next, Elevation, Glide Ratio, Glide Ratio To Destination, Heading, Odometer, Off Course, Pointer, Speed, Speed – Maximum, Speed – Moving Average, Speed – Overall Average, Sunrise, Sunset, Time To Destination, Time To Next, Time of Day, To Course, Trip Odometer, Trip Time – Moving, Trip Time – Stopped, Trip Time – Total, Turn, Velocity Made Good, Vertical Speed, Vertical Speed to Destination, Water Speed, Water Temperature, Waypoint At Destination, Waypoint At Next.

NAVSTAR – The original name of the GPS Satellite System. It stands for NAVigation Satellite Timing & Ranging.

Northing – This refers to the distance north or south of a fixed reference point such as the equator. You will see this value used in the UTM system and some others like the Military Grid Reference System (MGRS).

Parallel Lines of latitude, a term used in grid systems. A circle or approximation of a circle on the surface of the Earth. Parallel's are parallel to the Equator (0o latitude) and connecting points of equal latitude.

Precision Code (P code) – This is another GPS transmission code that relies on the CA code to function properly. The U.S. military and the U.S. Government use the P code. This code increases GPS accuracy to within a foot. The P code is not accessible to the public. This code is encrypted and reset weekly to prevent unauthorized use. Also known as the Y-Code.

Prime Meridian – The internationally accepted "prime meridian" located through Greenwich, England and has a longitudinal (vertical) measurement of 0 degrees.

Pseudo-Random Code – Helps to separate the GPS Signal sent by the satellite and mirrored by the receiver from background noise.


Q-Z

Quadrifilar Helix Antenna – A type of GPS antenna (used in the GPSMAP 60 Series) and others that is more sensitive then a patch antenna and is capable of searching for satellites on a 360o 3D plain. This type of antenna contains four spiraling elements that are contained within a plastic case for protection and durability.

Selective Availability – Intentional random error distributed by the U.S. Government that can be added to GPS signal to degrade accuracy. SA is currently disabled.

Statue – The U.S. unit of measurement, such as: feet, Fahrenheit, & miles. Grid System Preference: Latitude & Longitude.

Triangulation – Uses the laws of trigonometry to determine the location of an unknown point. This is similar to Trilateration.

Trilateration – A method of mathematics for determining the intersection of three or more spheres when the center and radii's of those spheres are known. Ttrilateration is used is in GPS technology. The GPS receiver calculates the intersecting point of 3 or more satellites which in turn gives the GPS the coordinates of where the individual with the GPSr is standing on earth.

True North – aka Grid North, both are used interchangeably. Simply the direction to the North Pole, but the North Pole is not magnetic north. The difference between the two is called declination. Similar to grid north

Universal Transverse Mercator (UTM) – A global grid system that splits the earth into 60 zones, each zone of which is 6o wide. This system starts at the equator (0o) and a zone meridian (180o, International Dateline in reference to latitude & longitude) and uses letters of the alphabet along with eastings & northings. UTM stands for Universal Transverse Mercator. This system is popular for use on land. Unlike lat. & long., which projects imaginary grid lines on the globe. UTM projects section of the globe on a flat surface, like a map. Again there are 60 sections or zones in the UTM system that cover 6o each. This type of grid system starts with section 1 at 180o - 174o, continuing east to zone 60. Two other elements describe this system in greater detail; they are easting and northing values. Easting & northing values measure how far in meters, within the zone the reference point is. Eastings measure east/west and northings measure north/south. Ex. 18 T 363327 4591410 “Split Rock" on the Loyalsock Trail. This landmark is a cool rock that split over time creating crevasses between the rock. The neat thing about UTM is, you can compare the distance between two reference point by taking the difference of the two coordinates (along as they are within the same zone).




Great Links

Latitude & Longitude


Universal Transverse Mercator


Military Grid Reference System


Universal Polar Sterographic System


Ordinance Survey Great Britian


Maidenhead Grid System




Questions or Comments?: Please feel free to email me, I would appreciate them, Thanks!

*Please, if this site as helped you in anyway and you would like to give back, donate by clicking the link found on the bottom left navigation bar. It takes many hours to update, post, check the data and its accuracy. Any contributions would be greatly appreciated. Thank you! Last Updated On:  August 6, 2013


Disclaimer
*Please remember, the information posted on this page and all other pages can & probably will change. I assume no liability for accidents happening to, or injuries sustained by, readers who engage in the activities posted on my entire website including links. Remember, you are responsible for your own actions, please understand conditions on the trail, in the woods or on the river can/will change due to mother nature. Please don't assume I know all there is about such topics, unfortunately I do not. I am just posting my travels and opinions experienced out in the wilderness. I encourage you to read further and look to reliable resources like the PA Game & Fish Commission and the PA DCNR. Thank You.