Q. What do you mean by Synoptic Coverage?
Depending upon the area of interest, areas covering few hundred sq m to thousands of sq km can be suitably collected and studied. Photo 3.3 shows an example of the advantage of satellite data over index plans due to synoptic coverage. Satellite imageries of river Brahmaputra covering a length of about 150 km and about 10 km are shown on the right. Corresponding index maps prepared using other available maps are shown on the left side. Bridge engineer may consider this aspect equivalent to the plane table survey plan, drawn at a suitable scale. In this view, satellite imageries serve the same purpose, but with more accuracy and dependability.