GPS Basic Presentation
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Transcript of GPS Basic Presentation
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
Check out my blog athttp://freegeographytools.com
Articles on GPS, GIS, maps, data sources, and much more...