topic Re: How to convert data with .asc extension to raster or .shp file in ArcGIS Pro Questions

How to convert data with .asc extension to raster or .shp file

NadaKadhim — Wed, 15 Jan 2025 08:39:30 GMT

Hi,

Please, how to convert data with .asc extension to a raster or .shp file?

I need a little help.

Re: How to convert data with .asc extension to raster or .shp file

tikola — Wed, 15 Jan 2025 09:01:02 GMT

This depends what .asc contains. Bascially it can be several things depending where it is from:

1) Old Esri ASCII raster that contains a short header and then matrix form of pixel values

Esri ASCII raster format—ArcMap | Documentation

2) Or sometimes it is XYZ style list where we have just X,Y and Z coordinates in a text files - one coordinate per row

3) or sometimes it is just pixel values in matrix without any headers.

In any case it is some sort of text file containing raster or grid of pixels. It is impossible to say which variant it is as I have seen all these with .asc ending.

If it is old Esri .asc raster Pro should probably be able to open it more or less directly. If it xyz style then tools like this might work:

ASCII 3D To Feature Class (3D Analyst)—ArcGIS Pro | Documentation

If it is something else then you must invent the headers or find some other ways. In generally none should really anymore deliver raster in .asc format. I can see it still in some Geoid models here but I really see no point why to use it - unless of it is just old forgotten file found in somewhere.

Re: How to convert data with .asc extension to raster or .shp file

Eugene_Adkins — Wed, 15 Jan 2025 11:36:52 GMT

In addition to what @tikola said, here’s an older post from stack exchange, an older post from the community that used python as the solution, and some Pro documentation about the deprecated conversion tool.

Re: How to convert data with .asc extension to raster or .shp file

NadaKadhim — Wed, 15 Jan 2025 20:35:22 GMT

Thank you, Tikola, for your response. I took data from:

https://globalsolaratlas.info/download/iraq

It was a map with an extension .asc!

Re: How to convert data with .asc extension to raster or .shp file

NadaKadhim — Wed, 15 Jan 2025 23:15:59 GMT

I appreciate your help, I have tried many but it does not work!

Re: How to convert data with .asc extension to raster or .shp file

Luke_Pinner — Thu, 16 Jan 2025 06:44:45 GMT

They are definitely Esri ASCII Raster format (and seem ok to me though I'm not at work so couldn't test in ArcGIS and only tested in QGIS).

But if you can't open them that page also lists GeoTIFF as a download option which ArcGIS also supports.

Re: How to convert data with .asc extension to raster or .shp file

NadaKadhim — Thu, 16 Jan 2025 12:25:27 GMT

Thank you Luke for your reply. I will try to work on GeoTIFF.

Re: How to convert data with .asc extension to raster or .shp file

tikola — Thu, 16 Jan 2025 14:30:34 GMT

Tiff is simplest. No point of fighting with ancient formats if there is basic things like TIF available. That is for sure just drag&drop and works always.

Re: How to convert data with .asc extension to raster or .shp file

NadaKadhim — Fri, 17 Jan 2025 08:44:19 GMT

Yep, this is true. But, again, could you please help me derive the shapefile from the raster format in ArcGIS Pro? My goal is to get the attribute data behind these maps!

Re: How to convert data with .asc extension to raster or .shp file

Luke_Pinner — Sat, 18 Jan 2025 01:28:27 GMT

Why do you think you need to convert raster to vector? You can still access the attribute data as raster.

Re: How to convert data with .asc extension to raster or .shp file

NadaKadhim — Sat, 18 Jan 2025 09:42:04 GMT

Great!

Please how? Could you teach me or guide me on how can I access the attribute table because it is not active?

Re: How to convert data with .asc extension to raster or .shp file

NadaKadhim — Sun, 19 Jan 2025 21:41:10 GMT

Please, tell me how? @Luke_Pinner

Re: How to convert data with .asc extension to raster or .shp file

Luke_Pinner — Wed, 22 Jan 2025 07:59:31 GMT

Can't really say without more information about what you're trying to do. Raster analysis is a bit different to vector and the choice of tool depends on what you're trying to achieve.

Re: How to convert data with .asc extension to raster or .shp file

tikola — Fri, 28 Feb 2025 17:33:55 GMT

Missed this old posting and disccussion. It looks obvious that your data is some sort of binary or limited amount of pixel values. So I guess your request is how to convert thematic rasters to vector GIS formats. You should be abe to do it with geoprocessing tools like Raster to Polygon or something like that. Software needs to delieneate areas with equal pixel values and that is your vector file out from this data.

Re: How to convert data with .asc extension to raster or .shp file

NadaKadhim — Sun, 27 Apr 2025 14:46:03 GMT

Thank you for your reply 🙂

Re: How to convert data with .asc extension to raster or .shp file

NadaKadhim — Sun, 27 Apr 2025 14:46:32 GMT

Many thanks for your response.