Most, if not all, of the images you see
on the Internet are raster images. Raster images are composed of small
points of color data called pixels (short for "picture element").
The advantage of raster images is the ability to represent complex shapes
and colors in a relatively small file format. Photographs, for example,
are represented using raster images.
|Raster Images Used on Alabama Maps|
All of the maps in the Contemporary Map Index are available as a JPEG (.jpg) download. If you wish to view our maps only on your screen (and not print them), then JPEG files are the best option to choose. Our maps in this section are at a sufficiently high DPI (dots per inch) to be viewed in detail without the need to zoom.
Maps in the Historical Map Archive are in MrSID format, a "wavelet" compression format designed to store large images for viewing on the Internet. MrSID functions by decompressing only the section of the map you are interested in (zoomed into). As such, you may only print or save (accessed via right clicking on the image) the part of the image you are currently viewing. If you require the map printed in its entirety, submit a quote request and we will respond with the cost to reproduce the map.