Creating seamless digital maps from Survey of India topographic sheets

It is possible to create seamless digital maps from Survey of India topographic sheets, by separately georeferencing each N-S strip of sheets which share the same projection to a separate metric grid, back-projecting from the separate metric grids to geographic coordinates on the Everest 1956 elipsoid, and then joining the strips. This method can also combine maps from different scales. The procedure is explained in detail using Arc/Info terminology, and outlined for ILWIS 2.1 for Windows.

• Introduction
  • (1) Create a separate grid coordinate system for each N-S strip
  • (2) Create a geographic grid and projected tics
  • (3) Register maps to projected tics
  • (4) Digitize
  • (5) Project coverages to geographic coordinates
  • (6) Join coverages into one seamless map
• Variations
• Discussion
• Postscript: geo-referencing maps with no coordinates

URL: http://www.itc.nl/personal/rossiter/pubs/GISIndia.htm
Last Updated: 2004_309