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I have an ASCII file that I converted to a raster. My heading on the ASCII file is:

NCOLS 156

NROWS 720

XLLCORNER -170989.3011812 m

YLLCORNER 1417628.464462 m

CELLSIZE 1

2 2 2 2 2 2 23 23 23 23 23 23 23

I want the raster to overlap a shapefile that have the above coordinates. The shapefile is a simple grid. For some reason, when I apply the raster to the map, it is located at the point 0,0 (Just off the coast of Africa.)

Has anyone ran into this problem before?

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  • Have you checked that the coordinate systems are the same? Also, don't you need a Upper right coordinate as well as a Lower Left (LL)?
    – Andrew Tice
    Jun 10, 2015 at 22:52
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    Ah, I forgot to mention that when I add the raster to the map, it says unknown spatial reference. Not sure how to fix that.
    – jcronin
    Jun 10, 2015 at 22:56
  • Hi @jcronin, if you converted the ascii to raster, then you should be able to Define the coordinate system.
    – TsvGis
    Jun 10, 2015 at 23:08
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    Check that if you add the raster by itself to a new map that you're seeing the correct coordinates from the header. After that, add the shapefile, does it overlay? If it does, the raster has the same coordinate system. If it doesn't, the raster doesn't have the same coordsys and you're going to have to either figure it out, or georeference it to the shapefile.
    – mkennedy
    Jun 10, 2015 at 23:09
  • I'd remove ' m' from header. Also 'no data' line is missing resources.esri.com/help/9.3/arcgisengine/java/GP_ToolRef/…
    – FelixIP
    Jun 11, 2015 at 4:04

1 Answer 1

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You have a coordinate in your ascii for georeferencing but it does not tell anything about the coordinate reference system (CRS). Use the "Define Projection" tool from the toolbox to add a spatial reference to your raster and your shapefile. (It looks like UTM?).

If they both are in the same reference system they will be displayed on top of each other.

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