topic Re: Create raster from multiple .asc rasters in ArcGIS Pro Questions

Create raster from multiple .asc rasters

GlenShennan — Sun, 18 Apr 2021 02:28:11 GMT

I am trying to load ~2000 rasters stored as .asc files and merge them into one raster. The Copy to Raster tool doesn't seem to recognise them (they don't appear in the browser when I load the tool) and neither does the Add Data tool. I can see them in the catalog and load them into the map that way but dealing with that many layers is extremely difficult.

Can anyone suggest an approach for an efficient (as in my time) way to merge that many ASCII rasters into one layer (I'm thinking TIFF) and load them into my geodatabase? I've been exploring the Create Raster Dataset and Mosaic to New Raster tools but just can't work out exactly what I should be doing.

As always thanks in advance.

P.S. I have a feeling that ArcPy is going to be the way to go and I've been trying that too but I'm new to ArcPy I'm not really sure which tools to use. Comfortable with Python though.

Re: Create raster from multiple .asc rasters

DanPatterson — Sun, 18 Apr 2021 03:34:10 GMT

Although deprecated, did you look at

ASCII To Raster (Conversion)—ArcGIS Pro | Documentation

if Copy Raster isn't seeing the .asc file extension

Addendum

I remember this protracted discussion before.

Problems with ASCII to Raster in ArcGIS Pro 2.6.x - Page 2 - Esri Community

I haven't had issues, but at least one thread, and there was a bug associated with the header not being read if it were in capitals. It should be fixed, but it was never marked resolved.

Re: Create raster from multiple .asc rasters

GlenShennan — Sun, 18 Apr 2021 03:39:21 GMT

ASCII to Raster doesn't appear to be in ArcPro 2.7. Checked the headers, all lower case. 😕

Re: Create raster from multiple .asc rasters

curtvprice — Sun, 18 Apr 2021 04:01:35 GMT

I just tried this with Pro 2.7.2 and Pro recognized the .asc files just fine (both in the Catalog pane and in the Copy Raster tool dialog). What version are you using?

If there are 2000 of them, you may want to convert to .tif and then consider create a mosaic dataset, then maybe Copy Raster to convert that to a single massive gdb raster or tiff.

If you are familiar with python, just get the syntax of the Copy Raster tool by running it once, right clicking on the geoprocessing history for the tool and copy with python snippet, and paste into python and write a loop around it, sticking your loop variables in it.

Try this test raster to see if the problem is your data set (save as "test.asc")

NCOLS 5 NROWS 5 XLLCORNER 0 YLLCORNER 0 CELLSIZE 1 NODATA_VALUE 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

Re: Create raster from multiple .asc rasters

GlenShennan — Sun, 18 Apr 2021 04:53:36 GMT

Ah, thanks! I saved your test data as 'test.asc' but Copy Raster still didn't see it. Your data has all caps in the header whereas mine is all lower case so I don't think that's the problem.

I used your trick to get the Copy Raster Python syntax and it works! I haven't got it all finished but that's a great start. Thanks.