Fix original Indian constituency shapefiles lacking projection information

by NewToGis   Last Updated November 08, 2018 22:22 PM

I found original Election Commission of India shapefiles containing constituency boundaries prior to delimitation using the Wayback Machine. These shapefiles are available here:

https://web.archive.org/web/20050404010832/http://www.eci.gov.in:80/GisLayers/Gis_fs.htm

Note that when you project the Parliamentary constituencies (anything from the "PC Boundaries" file in the link) using EPSG 4326, the constituencies are projected correctly.

However, when you attempt to project Assembly constituencies (the "AC Boundaries" file in the link) then, using EPSG 4326, the constituencies are projected to the west and are much smaller than they should be.

I have tried using every possible projection that comes to mind when dealing with Indian data, however, I am at a loss with regards to several points:

  • the data is projected far to the left. This suggests that the projection used was not one that was adequate for India
  • the units do not appear to conform to either degrees or meters. If a projection that admits degrees is used, then the areas are around 12 times smaller than they should be. If a projection that admits meters is used, then the areas are around 1180000 times smaller than they should be
  • the general shapes and proportions seem about correct when using EPSG 7755, which is a projection for India using Lambert Conformal Conic and the WGS84 datum, however, since EPSG 7755 admits meters, the scale is 1180000 times smaller than it should be and the area of projection is to the east.

Does anyone know what kind of transformations could have been applied to this data causing the highlighted issues, and, even more importantly, does anyone know if it is possible to reverse these?



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