This chapter’s lab will examine using the Global Positioning System for a variety of activities. The big caveat is that the lab can’t assume that you have access to a GPS receiver unit and would be able to use it in your immediate area
(and unfortunately, we can’t issue you a receiver with this book). It would also
be useless to describe exercises involving you running around (for instance)
Boston, Massachusetts, collecting GPS data, when you may not reside anywhere close to Boston.
Thus, this lab will use the free Trimble Planning Software for examining
GPS satellite positions and other factors used in planning for the use of GPS
for data collection. In addition, some sample Web resources are used to examine related GPS concepts for your local area.
For some good introductory information about Trimble Planning
Software (whose info helped guide the development of this lab), also
check out the article written by Leszek Pawlowicz titled “Determining Local GPS Satellite Geometry Effects On Position Accuracy.” This
article is available online at http://freegeographytools.com/2007/
determining-local-gps-satellite-geometry-effects-on-position-accuracy.
Important note: Though this lab is short, it can be significantly expanded
if you have access to GPS receivers. In that case, some of the geocaching exercises described in Section 4.5 of this lab can be implemented. Alternatively,
rather than just examining cache locations on the Web (as in Section 4.4), you
could use the GPS equipment to hunt for the caches themselves.
Objectives
The goals for you to take away from this lab are:
a Examine satellite visibility charts to determine how many satellites are
available in a particular geographic location, as well as when during the
day these satellites are available.
a Read a DOP chart to determine what times of day have higher and lower
values for DOP for a particular geographic location.
a Explore some Web resources to see where publicly available geocaches or
permanent marker sites are that you can track down with a GPS receiver.
Obtaining Software
The current version of Trimble Planning Software (2.9) is available for free
download at http://www.trimble.com/planningsoftware_ts.asp.
4.1 Geospatial Lab Application
GPS Applications
91
(and unfortunately, we can’t issue you a receiver with this book). It would also
be useless to describe exercises involving you running around (for instance)
Boston, Massachusetts, collecting GPS data, when you may not reside anywhere close to Boston.
Thus, this lab will use the free Trimble Planning Software for examining
GPS satellite positions and other factors used in planning for the use of GPS
for data collection. In addition, some sample Web resources are used to examine related GPS concepts for your local area.
For some good introductory information about Trimble Planning
Software (whose info helped guide the development of this lab), also
check out the article written by Leszek Pawlowicz titled “Determining Local GPS Satellite Geometry Effects On Position Accuracy.” This
article is available online at http://freegeographytools.com/2007/
determining-local-gps-satellite-geometry-effects-on-position-accuracy.
Important note: Though this lab is short, it can be significantly expanded
if you have access to GPS receivers. In that case, some of the geocaching exercises described in Section 4.5 of this lab can be implemented. Alternatively,
rather than just examining cache locations on the Web (as in Section 4.4), you
could use the GPS equipment to hunt for the caches themselves.
Objectives
The goals for you to take away from this lab are:
a Examine satellite visibility charts to determine how many satellites are
available in a particular geographic location, as well as when during the
day these satellites are available.
a Read a DOP chart to determine what times of day have higher and lower
values for DOP for a particular geographic location.
a Explore some Web resources to see where publicly available geocaches or
permanent marker sites are that you can track down with a GPS receiver.
Obtaining Software
The current version of Trimble Planning Software (2.9) is available for free
download at http://www.trimble.com/planningsoftware_ts.asp.
4.1 Geospatial Lab Application
GPS Applications
91