As far as I understood a shapefile is either defined as being a Projected Coordinate System or a Geographic Coordinate System. (Seeing as it is just a bunch of numbers and a coordinate system/metadata to define what they mean)
However, in ArcMap, some of my shapefiles have both projected and geographic coordinate systems defined. (See quoted section below).
What's going on here? And how can I define the projected coordinate system for another shapefile that is only currently defined by the geographic coordinate system without completely converting it and losing the geographic coordinate system?
I find it hard to understand why geospatial processing functions don't all have in-built conversion methods. I'm pretty sure when I was using QGIS it just handles all the coordinate system stuff in the background.
The Layer Properties, Source tab:
Data Type: Shapefile Feature Class Geometry Type: Polygon. Coordinates have Z values: No . Coordinates have measures: No .
Projected Coordinate System: British_National_Grid . Projection: Transverse_Mercator . False_Easting: 400000.00000000 . False_Northing: -100000.00000000 . Central_Meridian: -2.00000000 . Scale_Factor: 0.99960127 . Latitude_Of_Origin: 49.00000000 . Linear Unit: Meter .
Geographic Coordinate System: GCS_OSGB_1936 . Datum: D_OSGB_1936 . Prime Meridian: Greenwich . Angular Unit: Degree .