Ask A Cartographer

Projection of UTM 48N

February 12 2010 | 0 comments
Categories: Map Data

The other day you helped me find the UTM48N. I projected the new shape files. Reprojected a raster whose orginal was "undetermined'. When I reprojected roads the roads did not line up with the roads on the satellite. Looks like the one is in meter and one in dec. deg. I have converted my LAT/LONG to dec. deg. Then I have the scanned in topo map (beautiful) opened as png to reproject to put the points on. I want this in degrees. I also need to know where I can get Indian Coordiinate System UTM 1054? I "saw" it someplace. What do I do about units?

Mapping Center Answer:

OK -- the easy answer first -- the Indian UTM 1054 coordinate system is most likely the Indian 1960 UTM Zone 48 N Coordinate System (in the Predefined -> Projected Coordinate System -> UTM -> Other GCS folder). We are surmising that this is the case because that projected coordinate system has as its central meridian 105 E. Perhaps the "4" in the coordinate system you inquired about is really an "E".

Now on to your other question -- I think you might be starting off on the wrong foot. if you do not know the projection of the raster data, you cannot simply define it as other projection you want it to be. You need to use the Define Projection tool to specify what the projection is of the source dataset is, then use the Project Raster tool to project the raster to a different projection, if that is what you need. for that matter, if the projection was not defined for your original shapefile data and you projected it to the UTM48N projected coordinate system, you might have a problem with hose data as well.

In summary -- before you project your data, you need to know the coordinate system for the original data. If this information is not already specified for your data, you need to specify it explicitly using the Define Projection tool. Then you can project your data to the new coordinate system. Be sure to select the correct transformation when you do this re-projection. A while back, we wrote a blog entry on geographic transformations and how to choose the right one -- you might to read that if you are unsure about the requirements for geographic transformations.

If you would like to post a comment, please login.

Contact Us | Legal | Privacy |