May 27, 2005
Geospatial Applications: GIS Programs for Hand-held Computers
Handheld computers, often called PDAs, provide users with opportunities to have real-time geographic information system/global positioning system information in field situations.
GIS software programs are computerized mapping programs used to display maps and other spatial data on computer monitors. The portability of hand-held computers facilitates outdoor use and the addition of GPS (global positioning system) signals allows users to display maps with the real-time position shown on the maps.
There are several GIS software programs available for hand-held computers. Some programs are written for specific uses, but others are more general and have broader applications. Hand-held computer users find the programs vary widely in capabilities and ease of use, and have specific functions.
When choosing a GIS software program for a hand-held computer, it is important to remember the field-use features you need for your application, as well as the storage format for the data and how the data can be transferred to desktop computers. Many users collect spatial data in the field so they can use it for management decisions later, usually in a software program in an office computer.
Farmers use hand-held computers with real-time GPS for many jobs including marking field and area boundaries, displaying yield data and remotely sensed images in the field, and as controllers for variable-rate application and guidance equipment. Some of the hand-held GIS programs include databases of crops, weeds and crop inputs to facilitate drop-down menus that make field data collection more convenient.
Several GIS programs for hand-held computers are designed specifically for farm use, including AgGPS® EZ-Map, Pocket DLog and Site Mate. Others, such as ArcPad and HGIS, are designed for general use, but have features that make them very useful for farm and other industry-specific uses. I will evaluate several GIS programs for hand-held computers during the next several weeks, beginning with ESRI’s ArcPad.
ArcPad operates on Windows operating systems, including Pocket PC and Windows CE. ArcPad uses the ESRI shapefile format to display GIS layers and collect data. It supports MrSid, JPG, BMP and PNG image formats.
Data collected with ArcPad is versatile because most GIS desktop programs support shapefiles. ArcPad supports NMEA, TSIP, Earthmate and PLGR GPS data formats. The NMEA format is a standard GPS data protocol format. The other GPS formats are proprietary formats from companies that sell GPS equipment.
ArcPad’s screen display includes a position window that indicates the number of GPS satellites being used and their signal strength. The position window also displays the position coordinates, speed, elevation, bearing and estimated position accuracy. The position coordinates can be set to display in several coordinate systems.
Since ArcPad is designed as a general-use GIS program, more training is needed to use it than other hand-held GIS programs designed for specific industries. For example, creating layers involves a four-step process that must be completed before the user can start collecting data. ArcPad can be altered to fit specific applications.
Even though ArcPad requires learning some GIS software skills, it is a good choice for collecting and displaying spatial and image data. Users willing to take the time to learn to use it will appreciate its many functions and versatility. ArcPad costs approximately $400.