How can I identify an unknown coordinate system?
Coordinate system information is usually obtained from the data source, but not always, as with legacy data. The technique described below helps to identify the correct coordinate system. If the coordinate system is unknown you will receive a warning message when trying to add the layer to ArcMap.
How to find an unknown coordinate system in ArcMap?
Start ArcMap with a new empty map and add the data with the unknown coordinate system. The data must not have a defined coordinate system. For shapefiles, it must not have a PRJ file.
What happens if data does not have a defined coordinate system?
If data does not have a defined coordinate system, ArcMap cannot project it on the fly. ArcMap simply will draw it. If you change the data frame’s coordinate system, all layers that have coordinate systems will be projected on the fly to the new coordinate system.
Where can I find the correct coordinate system?
Coordinate system information is usually obtained from the data source, but not always, as with legacy data. The technique described below helps identify the correct coordinate system.
How to identify coordinate system of shapefile when unknown?
Project your known coordinate system layer into each projection until you find one that matches the unknown layer as much as possible. Since this question never gets old, I built a site that does the Brute Force method.
Where can I find a coordinate reference system?
In my particular case I know only the system is in meters, has origin (probably of zone) at E 91°30′ and N 50°20′ (not 100% sure about exactly 50°20′) and it is presumably commonly used in Russia. I would be glad for general solution if any.
How do I add an unknown coordinate system to ArcMap?
Start ArcMap with a new, empty map, and add the data with the unknown coordinate system to the map. This data must not be associated with a PRJ file or coordinate system definition. Right-click the layer name in the Table of Contents, select Properties > Source tab, and examine the extent of the data.
What happens if you change the data frame’s coordinate system?
If you change the data frame’s coordinate system, all layers that have coordinate systems will be projected on the fly to the new coordinate system. If you set the data frame’s coordinate system and the data with a known coordinate system lines up with the unknown data, the data frame’s coordinate system is that of the unknown data’s.