| Introduction | |
| About GIS |
|
| Navigation Links | |
| Home |
|
| RAC Home |
|
Data Capture
How can a GIS use the information in a map? If the data to be used are not already in digital form, that is, in a form the computer can recognize, various techniques can capture the information. Maps can be digitized, or hand-traced with at computer mouse, to collect the coordinates of features.
Electronic scanning devices will also convert map lines and points to digits.
A GIS can be used to emphasize the spatial relationships among the objects being mapped. While a computer-aided mapping system may represent a road simply as a line, a GIS may also recognize that road as the border between wetland and urban development, or as the link between Main Street and Blueberry Lane.
Data capture - putting the information into the system - is the time-consuming component of GIS work. Identities of the objects on the map must be specified, as well as their spatial relationships. Editing of information that is automatically captured can also be difficult. Electronic scanners record blemishes on a map just as faithfully as they record the map features. For example, a fleck of dirt might connect two lines that should not be connected. Extraneous data must be edited, or removed from the digital data file.
The content of this page was copied from USGS Website.
For more information please refer to the site: mapping.usgs.gov
