GPS Basics: Tips, Tricks And Free Tools To Get The Most From Your Handheld GPS Receiver

Leszek PawlowiczJune 24, 2010

Field Help/Training SessionSunday, June 27th, 10-12

(details at end of talk)

Topics To Be Covered

Tips and tricks to make GPS work better for you

Basic functions of handheld GPS units

What kind of data can GPS display and record

Using a GPS with paper maps

Moving data from a GPS to your computer, and displaying it on a map

Creating position points/tracks on your computer, and transferring them to your GPS

Putting maps on your GPS

Free data and software to use with your GPS

What Is GPS?

GPS = Global Positioning System

“The Global Positioning System (GPS) is a space-based global navigation satellite system that provides reliable location and time information in all weather and at all times and anywhere on or near the Earth there is an unobstructed line of sight to four or more GPS satellites.” - Wikipedia

Or …

GPS tells you where you are.

My GPS Receivers Over The Years

Motorola Traxar - 1993

Garmin 60Cx - 2006

Garmin eMap - 1999

Magellan Triton 2000 - 2008

RTFM- Read The Friendly ManualEven for old GPS units, the manual is usually available for download

on the manufacturer's website in PDF format.

Basic operating instructions

Advanced functions

Other useful info (batteries, how to hook it up to a computer)

And while you're at the website, check for a firmware update. Firmware = The software that runs your GPS.

Updates fix bugs in software, add new features.

Check the manual or website for instructions on how to update firmware.

Before you take your GPS outside ...

Get a case Get a screen protector (zagg.com) Check your sunglasses (non-polarized best) Pack spare batteries

GPS On => Satellite Acquisition

Open bar => Satellite signal acquired – all data not yet acquired

Filled-in bar => Satellite data acquired (time and position)

Height of bar => Signal strength

GPSr needs to acquire data from four or more satellites widely spaced across the sky to calculate a position; this takes time.

What's My Position?

All GPS units (even the oldest) have a “data screen” that lets you display your current coordinates, and

often other data (speed, altitude, time, distance, etc.).

More recent units may have a “map screen” where you can also choose to view your current coordinates and

other data.

Modifying The Data Screen

Many GPS units let you choose which parameters to view on this screen.

Some units let you display fewer parameters, but with larger text.

What are coordinates without a map? Just numbers ...

Older GPS units may not display mapsNewer units do but screen size too small for sense of geographic contextBuilt-in map on many units often inadequate for navigation

Most importantly: GPS units can break or fail (e.g. dead batteries) => Unless you're thoroughly familiar with an area, you ALWAYS

need a paper map (and compass) as backup

Sources For Free USGS Topo MapsSingle maps

LibreMapshttp://libremap.org/data/

Arizona Regional Image Archivehttp://aria.arizona.edu/

USGS Map Locator (PDF format)Go to http://store.usgs.gov/b2c_usgs/b2c/start/(xcm=r3standardpitrex_prd)/.do and click on the “Map Locator” link

DDS MapFinder – Google Earth linkhttp://freegeographytools.com/2007/identify-and-download-usgs-24k-topographic-maps-in-google-earth

US Forest Service updated topo mapshttp://freegeographytools.com/2007/updated-usgs-24k-topographic-maps-from-the-us-forest-service

Seamless maps

USGS Seamless Serverhttp://seamless.usgs.gov

USAPhotoMaps (free Windows program)http://jdmcox.com

Old USGS Topo Map Updated USFS Topo Map

Printing USGS Topo Maps On A Small Printer

Standard 1:24,000 USGS topo maps are 22” x 27”; printing them on a 8.5” x 11” sheet of paper can shrink detail to where it can't be seen clearly.

Options:

Open map in a graphics program, crop out everything except a small area, and print just that small area.

Use a graphics/printing service that prints larger (“poster”) sizes (WalMart, Staples, OfficeMax, Sams Club, Kinko's, etc.)

Chop map image into small subsections (tiles) that will each fit on a single sheet of paper, then tape all subsections together into complete map

Graphics programs Posteriza http://www.posteriza.com/es/index.php?lang=en_US Posterazor http://posterazor.sourceforge.net/ Picasa http://picasa.google.com/ Printer driver or support software

Tiling with Canon printer driver

Using the coordinates on the edge of the map

Map Coordinate System Info – Usually Found Somewhere On The Map

UTM Easting

Northiig

Coordinates set to latitude/longitude

Coordinates set to UTM

Datum set to NAD27

Display coordinates need to match the ones you're using on the map

Recording your position with your GPS

Waypoints – “planting a flag” to mark your position

Most GPS units let you mark a waypoint with a single button that brings up a data screen, modify the waypoint, and save it

You can display a list of your saved waypoints ...

Select one, choose “Go To” ....

And see where it is relative to you, and what direction you need to go in to get to to it.

GPS Tracks – A Virtual “Trail Of Breadcrumbs”

Turn track recording on and offView a list of tracks stored on your GPSChange track parametersShow them on mapNavigate back along them. Set how frequently a “breadcrumb” is “dropped”.

Working With GPS Tracks

How Accurate Is A GPS Position?

Many GPS units display “accuracy” value

95% confidence that GPS-derived position is no farther than accuracy value from true position

IMHO, this number is conservative for newer GPS units, and the GPS position can be much closer to the true position …

… but there's always a level of uncertainty

Accuracy depends on many parameters

http://freegeographytools.com/2008/improving-position-measurement-accuracy-in-consumer-grade-gps-receivers-part-i

http://freegeographytools.com/2008/improving-position-measurement-accuracy-in-consumer-grade-gps-receivers-part-ii

More info on how to maximize position accuracy / minimize uncertainty:

Getting Your Data Off Your GPS And Onto Your Computer

Why?

Plot it on a map

Share it with someone else

Combine it with other people's data for mapping projects

Save it so that you can delete it from your GPS, and put it back again when you need it

Save it so that if you lose your GPS, or get a new one, you can transfer the data back onto it

How Do You Connect Your GPS To A Computer?

- Newer GPS units usually connect with a USB cable

- Older units may require a special cable and computer interface

- Read The Friendly Manual to find out how to do this with your GPS unit.

GPS Software: From The Manufacturer

DeLorme – Topo 2010 (comes with unit)

Magellan: VantagePoint, MapSend Litehttp://magellangps.com

Garmin: Basecamphttp://www.garmin.com/garmin/cms/us/onthetrail/basecamp

GPS Software: Third-Party(May be only option for older units)

Free programsEasyGPS (http://easygps.com)OKMap (http://www.okmap.org)GPSMaster (http://www.gpsmaster.nl/index.htmlPrune (works on Mac) (http://activityworkshop.net/software/prune/)USAPhotoMaps (http://jdmcox.com)

Free for basic functions; paid for advanced useGPS TrackMaker (http://www.gpstm.com)OziExplorer (http://www.oziexplorer.com/)

Commercial applications (time-limited demo)ExpertGPS (http://expertgps.com)TopoFusion (http://topofusion.com/)

Basecamp Software Demos On YouTube

Part I – http://www.youtube.com/watch?v=m85sTGB4Sko

Part II - http://www.youtube.com/watch?v=Q4lBZ6m6jFU

Part III - http://www.youtube.com/watch?v=sbfcvMQBmJ0

Garmin Basecamp demo

Options for maps

1. Buy maps

Garmin CityNavigator, Topo 2008, Topo 24K

DeLorme – Comes with topo maps, can download subscription maps

Magellan – Can buy maps from Magellan, National Geographic Topo maps

2. Get maps for free ...

Sources for free US/AZ maps

Garmin:

GPS File Depot http://www.gpsfiledepot.comHigh-resolution (1:24K-equivalent) topo maps for most of USPre-packaged for easy installation

Desert Packrats http://members.cox.net/klaporte/dp_m1.htm Thematic maps of AZ: Geology, faults, vegetation, wells, dams, mines, etc.

Magellan:

maps4me http://maps4me.com

Demo of Arizona topo maps in Basecamp software

Demo of MapInstall

Map selection

Turn maps on and off in map selection screen.

Transparent map: Map details displayed on top of second map

View of map detail on GPS

“Normal” detail level

“Most” detail level

Field session

Sunday, June 27th, 10 AM – ~12 noonBuffalo Park, Flagstaff – park/meet near the buffaloLat/long: N35.21782, W111.63275 Datum: WGS84Prerequisites: A Garmin GPS unit you can bring and useLimited to 8 people (sign-up sheet)Water, hat, hiking boots, etc.

Optional “Homework” For Field Session

Read the manual (download and print it out if you don't have it)Turn on your GPS, and get a position fix at where you liveSave that position as a waypoint; change its name and descriptionWalk away from that position, set the just-created waypoint as your destination, and navigate your way backMake a track by walking along a linear feature (road, fence, etc.)Save that track under a new nameMake a track around an area, and save that trackDownload and install Basecamp on your computerIf compatible, connect and download the waypoints/tracks on your GPS to your computer, and view them in BasecampSave them as a GPX fileDownload and install the free Arizona topo map from GPS File DepotView your tracks/waypoints in Basecamp with the Arizona topo selectedIf compatible, upload the topo maps for the Flagstaff area to your unitDownload the topo map for the field session area (Flagstaff West)Print out a copy of the mapCreate a waypoint for Buffalo Park from the given coordinates

For individual GPS training, custom maps, and software consultation:Leszek Pawlowicz

leszekmp@gmail.com

Check out my blog athttp://freegeographytools.com

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