Which GPS Should I Buy

Joel CusickAlaska Support Office

Garmin

Trimble

PLGR

• Tips to Buying a GPS for Mapping

Pro XR

GeoExplorer 3

• What a GPS Mapping Receiver should do

• Overview of Main GPS Receiver Types

• PROS/CONS of Receiver Types

• The Best Tool for the Job

Outline

• You supervise people or work in one/many parks in Alaska

• You want to record your field locations or map existing infrastructure, trails– Use to navigate to/from– Archive the locations in a later in a GIS

• You have access to the wonderful AKSO Intranet and the X:drive

Assumptions

• Hardware

• Software

• Support

What a GPS Mapping Receiver should do

• Hardware– Accuracy (How close to Truth)

• Meet National Mapping Accuracy Standards:– 1:63,360 (32meters) – 1:24,000 (12 meters)– 1:5,000 (4 meters)

– Precise (How reliable)

– Rugged

– Able to Average a Point

– External Antenna options

– Good on Batteries

What a GPS Mapping Receiver should do

• Software– Export in GIS Friendly Formats (shapes, coverages)

– Capable of Controlling Attributes in the Field• Data Dictionary (Name, Trail Width, Comments)

– Capable of Datum Transform– Mission Planning

• Sky Plots

• Planning the day

– Run on standard PC / equipment

What a GPS Mapping Receiver should do

• Support (AKSO)– Manufactured by Trimble, Garmin or Rockwell– GIS Products that utilize ESRI - NPS Standard

• ArcView

• ArcInfo

– Ensure your data has long shelf life

What a GPS Mapping Receiver should do

• Recreational Grade GPS - Garmin

• Mapping Grade GPS - Trimble

• Y-Code Receivers - Rockwell PLGR+96

Overview of Main Types

• Features Include:– Wide Use -Alaska National Parks/AKSO = 60– Accuracy:

• Autonomous < 15meters 95% typical• DGPS ready 3-5 meters 95% typical

– User Friendly– Many models

• Garmin GPSIII+, GPSMap76, eTrex

– Moving Base Maps (1:100,000 scale)

Recreational Grade GPS - Garmin

Garmin

• Features Include:– Wide Use -Nationally

– AKSO (dozen)

– Accuracy: • Autonomous < 15meters 95% typical

• Post-Process DGPS– 3-5 meters 95% typical (Geo3)– 1 meter 95% typical (ProXR)

– Pathfinder Office Software• Data Dictionary, Mission Planning

Mapping Grade GPS - Trimble

Trimble

• Features Include:– Rugged– Good under Canopy– 999 Waypoint Storage– EHE displayed– Datum Switch seen in ASCII Out

Y-Code Receivers - PLGR+96

PLGR

• Garmin III+– Pros

• Cheap and consistent 15 meters positions - good under canopy• Good “Point tool”• Fun and easy to use• Integration into ArcView - relatively straightforward• Battery usage is great

– Cons• Cheap• Position accuracy not so trustworthy• Not designed for GIS Mapping - relies on 3rd party software• No Data Dictionary capability• Decent storage of tracks/waypoints (6-10 hours)

GPS for GIS - Pros and Cons

• Trimble GeoExplorer 3– Pros

• 1-5 meter mapping tool• Point/Line/Poly• Rugged• Collect for 16 hours• Software is excellent

– Cons• $4000• Firmware will be changing?• Under Canopy issues - must use antenna• No Data Dictionary• Very small storage of tracks/waypoints(999)• Need to post-process after the field (internet connection)

GPS for GIS - Pros and Cons

• Trimble Pro XR– Pros

• Top-of-the-line GIS Mapping Tool• Real-time DGPS• Point/Line/Poly• Good under Canopy• Rugged• Software is excellent

– Cons• $10,000• Big/Bulky• Firmware will be changing• Training involved

GPS for GIS - Pros and Cons

• PLGR– Pros

• Consistent 15 meters positions• Familiarity (bugs worked out)• Good “Point tool”• Rugged. Records error• Integration into ArcView - relatively straightforward

– Cons• Older technology• Heavy• Terrible on batteries• Club Fed only• No Data Dictionary capability• Very small storage of tracks/waypoints(999)

GPS for GIS - Pros and Cons

• Sorry… It’s a Multi - Tool Environment– Garmin– Trimble– PLGR

• Need to learn enough about each system to know when to use the tool– Mapping a trash can lid? - ProXR– Mapping a ATV trail - Garmin, Geo3 or ProXR– Mapping sheep from the air? - Garmin\PLGR– Mapping complex attributes? - Geo3 or ProXR– In Dense Canopy - PLGR / ProXR

Right Tool for the Right Job

• Garmin for navigation, point collection– Use DGPS system only if working along Gulf of

Alaska, Southeast, out on the water

• PLGR for dense people / dense canopy

• For Serious GIS– Trimble Geo3 for open country mapping– Trimble Pro XR for everything

Ideal GPS Toolkits

• Ask Yourself

• 1) What are your accuracy needs?– A) resolution of the other data types

– B) anticipated data for the future

• 2) Project Needs– A) What are your GIS skills

– B) Is it just you dealing with the data

• 3) What part of Alaska are you working in?

• 4) How much money do you have?

What is Best?

GPS Toolkits

• Winzip Executibles– Designed for distribution

– Embedded help sheets

• Yearly training Events– Orienteering

– Awareness Briefings

– Training• WRST (May 14-17)

• Accupoint (This summer)

GPS Training