Semi-Transparent Overlay of Two Raster Data Sources

TatukGIS Internet Server LITE Sample

		Zoom x2Zoom x8Center

Choose transparency level:	0% 20% 40% 60% 80% 100%
All tranformations are computed "on-the-fly" from 250MB TIFF file.

This TatukGIS Internet Server LITE sample presents the semi-transparent overlay of a segment of the DOQQ aerial photograph layer against the corresponding segment of the 1861 topographical map. (Select the desired transparency level.) In this fashion, one can easily see changes that have occurred in the subject area between the 1861 date of the historical map and the date of the DOQQ photographs (late 1990's).

Transparency manipulation can used with both raster and vector layers.

The above image was taken from the above map sample with a 40% transparency setting, and highlights the extent to which the banks of the north end of Theodore Roosevelt Island and along the Arlington, Virginia side of the Potomac River have changed during the last 140 years. The changes likely reflect dredging of the Potomac River to improve the waterway for commercial shipping and the extension of the land mass on the Arlington side to create room to build the George Washington Memorial Parkway. Clic here to see the source code for similar sample.