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I have an ASCII grid file that has rectangular cells. The ESRI documentation does not specify how to convert from .asc to raster with a DX/DY value such that:

NCOLS 1900
NROWS 1100
XLLCORNER 115.834717
YLLCORNER 31.638744
XCELLSIZE ...
YCELLSIZE ...
NODATA_VALUE 0

I do not want to read into a NumPy array. So how would one do this, be it manually, in ArcGIS?

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I suggest three steps workflow; (1) Edit header, (2) Import the file, and (3) Georeference it to its proper extent.

(1) Edit the header (XLLCORNER, YLLCORNER, CELLSIZE) to a dummy extent

NCOLS 1900
NROWS 1100
XLLCORNER 0.0
YLLCORNER 0.0
CELLSIZE 1
NODATA_VALUE 0

(2) Read this file by Ascii to Raster

(3) Georeference it by Warp

Source

0 0
1900 0
0 1100
1900 1100

Target

115.834717 31.638744
115.834717 + XCELLSIZE * 1900 31.638744
115.834717 31.638744 + YCELLSIZE * 1100
115.834717 + XCELLSIZE * 1900 31.638744 + YCELLSIZE * 1100

Above calculation comes from:

xLR= XLLCORNER + XCELLSIZE * NCOLS
yUL= YLLCORNER + YCELLSIZE * NROWS
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  • Effectively thats what I had to do but I just got the extent from the raster layer. In our original grid file, we already had the LL and UR values, so I just mapped to that; this however will allow for quicker calculations in ArcPy. So there is no way to use XCELLSIZE or YCELLSIZE inherently?
    – pstatix
    Jun 7, 2017 at 1:43
  • Unfortunately not, as far as I know.
    – Kazuhito
    Jun 7, 2017 at 2:03

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