I have recently begun to use ArcMap and needed some guidance on a problem that I am facing.

I have a district shapefile with 200 districts with geographic coordinate system: GCS_WGS_1984. I need to calculate the area of each district for which I am trying to project it with Asia Lambert Conformal Conic. But when I do this, the coordinate system displayed just stand froze i.e. it displays 95.001 30 decimal degree no matter where I put the cursor in the display.

Is there something wrong with the shapefile I have?

  • You could try using the Identify tool. Wherever you click to identify will have the coordinate in the id box. Have you tried projecting it with the GCS_WGS coordinate system? However, In order to measure the areas of your districts I believe you'll have to use a projected coordinate system. – gyoung1986 Dec 9 '14 at 14:37

I think you used the Define Projection Tool or the shapefile's property page (in ArcCatalog) to change the coordinate system to Asia Lambert conformal conic. That updated the metadata but didn't change the data's coordinate values.

Redefine it as WGS 1984. Use the Project Tool to make a copy. However, don't use Asia Lambert conformal conic, use Asia Albers equal area instead. If you're going to calculate areas, you should use an equal area projection.

OR, the data had no coordinate system defined (but you know it's WGS 1984) and you set the data frame's coordinate system to Asia Lambert conformal conic. Follow the steps above instead to get your areas.

Note: The 'freezing' is occurring because the software thinks the coordinate system is projected and using meters, but the data's actual coordinates are in decimal degrees and have a very small range of values.

  • Thanks for this. I tried your steps and it was successful. However, the coordinates are in meters but they are negative everywhere. Is it correct? And also the area calculated will be in meter-squared right? How do I convert it to km-squared? Thanks a lot for your advise – user53020 Dec 12 '14 at 12:34
  • If they're negative everywhere, it just means that the data is west of the central meridian and south of the latitude of origin. You could modify the false easting/northing values to make everything positive after you project, but it's not necessary. Q2: divide the results by 1000000? – mkennedy Dec 12 '14 at 17:49

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