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| Subject: | [gislist] Another GPS question: Answers |
| Date: |
03/17/2006 05:50:02 PM |
| From: |
Eric Sandoval |
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Thank you David Hughes and Armin Davis for responding. I've summarized their answers and included their original emails. Hope this helps others on the list.
Cheers,
-Eric
Recommended GPS device:
Delorme Blue Logger
Garmin E-Trex Venture
Recommended software:
Waypoint + http://www.tapr.org/~kh2z/Waypoint/
GPS utility http://www.gpsu.com
-----Original Message-----
From: gislist-bounces@lists.geocomm.com
[mailto:gislist-bounces@lists.geocomm.com] On Behalf Of Eric Sandoval
Sent: Monday, March 13, 2006 3:23 PM
To: gislist@lists.geocomm.com: gislist-bounces@lists.geocomm.com
Subject: [gislist] Another GPS question
Hello Listers:
I know this question has been asked a number of times and I wish I
would have saved some of the answers, but I need to post the question
one more time.
We are interested in purchasing some low cost GPS units. We already
own some Trimble high end units, but our budget has been slashed and we
would like to get some gps units in the $100-$200 (US) cost range.
Does anyone have a list, article or reference that is a comparative
evaluation of current equipment on the market?
Also, we've noticed that many low cost units (ie our current Garmin
units) don't allow the user to collect data in CA State Plane. Has
anyone out there come up with a solution for this problem, other than
collecting data and converting in a post-processing environment?
Thanks for your help.
-Eric Sandoval
David Hughes <david.hughes@wichita.edu> wrote:
It may go a shade above your bottom end, but I really like the Delorme Blue
Logger coupled with a Ipaq 4700 and ArcPad 6.0. That gets me to within a
meter more often than not and, when I need accuracy, it can log and provide
post-process data to get wihtin 10cm. I work mainly in UTM coordinates, but
suspect that the very inexpensive GPS utility available from gpsu.com will
provide accurate conversion (and download/upload/translation) from most gps
units into a wide variety of coordinate systems. Nice thing about GPSU is
that it also will read in, for instance, Garmin waypoint or tracklog files
and output them to an ESRI SHP file.
Dave Hughes
"Davis, Amin" <AKDAVIS@mactec.com> wrote: Subject: RE: [gislist] Another GPS question
Date: Tue, 14 Mar 2006 09:02:45 -0500
From: "Davis, Amin" <AKDAVIS@mactec.com>
To: "Eric Sandoval" <sandoval_ej@yahoo.com>
ERIC,
I'm forwarding an email I've sent coworkers. Considering costs
and utility, I recommend the Garmin Etrex Venture handheld unit. Feel
free to call me w/ any specific questions.
Take Care,
AMIN K. DAVIS
MACTEC Engineering & Consulting
3301 Atlantic Avenue
Raleigh, NC. 27604
Direct: 919-831-8058
Fax: 919-831-8136
________________________________________________________________________
____
GPS Overview
I have personally used all three major types of GPS units: (handheld,
handheld with WAAS capability, and mapping-grade (sub-meter)units). The
following link should give you a general overview of WAAS capability and
Garmin WAAS-enabled GPS units: the bottom of the page gives a good
overview of the relative accuracies of handheld GPS units.
http://www.garmin.com/aboutGPS/waas.html
For general mapping purposes, a handheld GPS unit is adequate. For
the money, I would recommend using a WAAS-enabled handheld unit. Garmin
sells a unit called the E-trex Venture which sells for under $150
including the PC cable. I've been told Garmin handheld GPS units have
better satellite tracking capabilities. ArcView 3.x extensions seem to
have better support for Garmin units. WAAS-enabled units are not
significantly more expensive than non-WAAS handheld units. GPS units
can be programmed to record points, tracks/routes (lines), or polygons
(areas).
Importing GPS readings taken using a handheld GPS unit (Garmin,
etc.) is relatively simple. You connect the PC cable of the unit to the
Com-port in the back of a computer (PC) and use software (I use freeware
called "Waypoint + found here: http://www.tapr.org/~kh2z/Waypoint/) that
uploads the GPS data from the GPS unit to a PC. Once this data is saved
into an ASCII file, it can be imported into a GIS software package
(Arcview) or CAD (AutoCAD/Microstation).
The survey grade GPS units can provide sub-meter accuracy after
the data is "differentially-corrected" (cleaned-up to remove extraneous
readings). In house, we have a Garmin GPS 12 (handheld w/out WAAS): the
other building has a Trimble Beacon receiver with TDC1 receiver
(survey-grade). For more info on Trimble GPS units, check:
http://www.duncan-parnell.com/mappinggis.html
Importing GPS readings taken using a survey-grade GPS unit is a
bit more complicated. However, the most important aspect of using these
units is making sure i
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