By purchasing the Georeferenced – JPG image file, the georeferenced World File (ie .jgw) will be included which provides the ability to import the image into GIS (ESRI ArcMap/ArcGIS) or CAD (AutoCAD) software. The world file is a plain text format which contains the geographic coordinates for the image. A ReadMe.txt file is also included with metadata such as projection, date, resolution and other important information. You can also purchase the Complete – All Files image download to receive a world file for each file format.
GIS stands for Geographic Information System, and it is a system for managing and utilizing data that is spatially referenced to the Earth. All of our images come with the necessary information to be imported into GIS software. For more information, consult Wikipedia.org.
CAD stands for Computer-Aided Design and it is a system that allows engineers, designers, architects, and other professionals to model a product or system on the computer and test it within a simulated environment. For more information, consult Wikipedia.org.
The world file contains six text lines that contain decimal numbers. Each line means the following:
Line 1: A, pixel size in the x-direction in map units/pixel Line 2: D: rotation about y-axis Line 3: B: rotation about x-axis Line 4: E: pixel size in the y-direction in map units, almost always negative Line 5: C: x-coordinate of the center of the upper left pixel Line 6: F: y-coordinate of the center of the upper left pixel