Data Collection for Woody Vegetation

Collecting GPS Points in Woody Vegetation

Data collection for woody species presents difficulties because of canopy density and cover. The easiest position in which to take data is usually at the drip line of a species. However, that information is difficult to assign to a remotely sensed image because the majority of a pixel’s reflectance is commonly influenced by the density of the canopy at the point of the image acquisition. The canopy of species is thinner at the drip …

Downloading GPS Data Using DNRGPS

John McGee, Virginia Tech


Note: several YouTube videos are also available to learn how to use DNRGPS



DNR Garmin was developed as an easy-to-use “point and click” software application that allows you to manage, manipulate, and save data from a Garmin GPS receiver for use in GIS programs such as ArcMap, MapWindow and AccuGlobe. DNR Garmin is shareware created and maintained by staff at the Minnesota Department of Natural Resources.  DNRGarmin works with ArcGIS 9.x, and was developed primarily …

DNRGPS Extension User Guide



DNRGPS is an easy-to-use software application designed to manage, manipulate, and save GPS and GNSS information for use in GIS software programs and geospatial viewers (GoogleEarth, etc.). DNRGPS is commonly used to transfer waypoint and trackpoint data between GPS/GNSS units and computers. The GPS unit is connected to the computer with a cable.

DNRGPS is designed specifically for Garmin GPS receivers, but this software also works well with any other NMEA output GPS receiver (which includes most recreational grade GPS …

Topography and Understanding Topographic Maps

usgs topographic map


Among the many mapping tools available, the most commonly used is the topographic map. Topography is defined as the relief (relative elevations) of a surface and the relative relations between its natural and man-made features. Topographic maps systematically portray the spatial relationship among both the physical features, such as contour lines (lines of equal elevation) and hydrographic symbols, and cultural features, such as roads and administrative boundaries. Topographic maps are also known as “topo maps.”


Reading a topographic map begins …

Selecting Handheld GPS Units

photo credit: UConn CLEAR

Selecting Handheld GPS Units

AE-1269 (Revised), October 2007

John Nowatzki, Extension Geospatial Specialist

Christopher Daigle, Mechanical Engineering Student

Global Positioning System (GPS) units are available for a wide variety of prices. The information presented in this document focuses on several of the least expensive models from several suppliers. The types of units discussed are handheld, flash-card, Bluetooth, and secure digital units. The units are compared for several operational features. The following paragraphs describe the comparative features …

GPS Applications in Crop Production

Image:Ae1264p1.jpgGPS and Agriculture

GPS Applications in Crop Production

John Nowatzki, Extension Geospatial Specialist
Vern Hofman, Extension Ag Engineer
Lowell Disrud, Assistant Professor
Kraig Nelson, Graduate Student

The Global Positioning System (GPS) provides opportunities for agricultural producers to manage their land and crop production more precisely. Common names for general GPS applications in farming and ranching include precision agriculture, site-specific farming, and prescription farming. GPS applications in farming include guidance of equipment such as sprayers, fertilizer applicators, and tillage implements to …

Geocaching – Getting Started page

Geocaching – Putting GPS to Work

What is Geocaching?

Geocaching is a recreational activity that involves hiding and seeking objects, or “caches,” usually with the aid of a global positioning system (GPS) receiver. You can think of geocaching as a high-tech treasure hunt. People hide caches and publish their coordinate locations to geocaching Web sites, thereby allowing others to use the coordinates to find the hidden caches. Geocaching is done on the honor system. After discovering a cache, finders sign …