topic Re: Export raster attribute table into CSV using Python automation ! in Python Questions

Export raster attribute table into CSV using Python automation !

YamMagar — Tue, 26 Nov 2013 01:25:27 GMT

Hello,

I am learning python scripting. I am trying to export raster attribute table (integer value) in to .CSV file. I can manually export attribute table into .txt file but would take many hours to export for 100 raster files. I have raster files (about 100) organized in a folder called "temperature". So, how can I write a python script that scan through all raster files and export attribute table of each raster into .CSV file with unique header file.

Thanks.

Re: Export raster attribute table into CSV using Python automation !

XanderBakker — Tue, 26 Nov 2013 08:03:59 GMT

Hi Milan,

Try the code below. Edit the following locations:

ws = this is the input workspace (folder) with all he rasters

outPath = is the folder where the output CSV files will be written

I have added the raster name as an additional field to the CSV.

import arcpy, os ws = r'C:\Project\_Forums\Viewshed\test.gdb'      # edit this outPath = r'C:\Project\_Forums\Viewshed\testexp2' # edit this outExt = ".csv"  arcpy.env.workspace = ws  rasters = arcpy.ListRasters("*") for raster in rasters:     rasloc = ws + os.sep + raster     fields = "*"     try:         lstFlds = arcpy.ListFields(rasloc)         header = ''         for fld in lstFlds:             header += ",{0}".format(fld.name)          if len(lstFlds) != 0:             outCSV = outPath + os.sep + raster + outExt             f = open(outCSV,'w')             header = header[1:] + ',RasterName\n'             f.write(header)              with arcpy.da.SearchCursor(rasloc, fields) as cursor:                 for row in cursor:                     f.write(str(row).replace("(","").replace(")","") + "," + raster + '\n')             f.close()      except:         print raster + " - is not integer or has no attribute table" del row

Example output CSV file:
OBJECTID,Value,Count,RasterName
1, 0, 1162115.0,Viewshed7
2, 1, 62868.0,Viewshed7

Kind regards,

Xander

Re: Export raster attribute table into CSV using Python automation !

YamMagar — Tue, 26 Nov 2013 11:43:21 GMT

Dear Xander,

Thank you so much for the code ! It worked in perfect manner :).

Re: Export raster attribute table into CSV using Python automation !

XanderBakker — Tue, 26 Nov 2013 11:50:26 GMT

Dear Xander,

Thank you so much for the code ! It worked in perfect manner :).

Hi Milan,

I'm glad I could be of any assistance. If you think it was helpful you can use the "arrow" button in order to help other members find useful information:

More info here: http://resources.arcgis.com/en/help/forums-mvp/

Kind regards,

Xander

Re: Export raster attribute table into CSV using Python automation !

JohnWani — Wed, 07 Sep 2016 16:49:18 GMT

Hi all,

I am new to GIS, I am having large number of raster files(800) in ArcGis and I want to copy the attribute table of each raster file separately to Excel.

I found your link through stack exchange and i want to use your code to perform the above mentioned task, if you can share the code with me as attachment as i try to run the script shared by you, it displays syntax error.

Re: Export raster attribute table into CSV using Python automation !

RebeccaStrauch__GISP — Sun, 12 Dec 2021 08:06:08 GMT

I haven't tested Xander Bakker‌ 's code, but here it is formatted (the old forum conversion scrambled some scripts)

import arcpy, os 
ws = r'C:\Project\_Forums\Viewshed\test.gdb'      
# edit this outPath = r'C:\Project\_Forums\Viewshed\testexp2' 
# edit this outExt = ".csv"  
arcpy.env.workspace = ws  
rasters = arcpy.ListRasters("*") 
for raster in rasters:
     rasloc = ws + os.sep + raster
     fields = "*"
     try:
          lstFlds = arcpy.ListFields(rasloc)
          header = ''         
          for fld in lstFlds:
               header += ",{0}".format(fld.name)
               if len(lstFlds) != 0:
                    outCSV = outPath + os.sep + raster + outExt
                    f = open(outCSV,'w')
                    header = header[1:] + ',RasterName\n'
                    f.write(header)
                    with arcpy.da.SearchCursor(rasloc, fields) as cursor:
                         for row in cursor:
                              f.write(str(row).replace("(","").replace(")","") + "," + raster + '\n')
                              f.close()
     except:
          print raster + " - is not integer or has no attribute table" 
del row  ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

If you are just getting into ArcGIS, you should look into Python (if you don't already know it) since that is the scripting language many of us use. Key about python, indentation is very important. Good luck.

Re: Export raster attribute table into CSV using Python automation !

JohnWani — Wed, 07 Sep 2016 17:06:58 GMT

Hi all,

The code now works for me but it displays the error message "is not integer or has no attribute table". But all the raster files have the attributes.

Please help

I will share some files with you if required.

Thanks and regards

Re: Export raster attribute table into CSV using Python automation !

JohnWani — Wed, 07 Sep 2016 17:11:37 GMT

@Rebecca Strauch, thanks a lot for quick response.

I also corrected Xander's code, it works fine and generates empty .csv files

But the error message 'is not integer or has no attribute table' is displayed.

Thanks again

Re: Export raster attribute table into CSV using Python automation !

RebeccaStrauch__GISP — Wed, 07 Sep 2016 18:18:35 GMT

I'm not a raster expert, but others here could probably help if you post something upload a sample.

Re: Export raster attribute table into CSV using Python automation !

XanderBakker — Sun, 12 Dec 2021 08:06:11 GMT

In theory everything that goes wrong inside the try except statements will yield that message. I put this message since in most cases the error would be caused by using a floating raster which does not have an attribute table.

You could change the last rows where the exception is caught into this to get more details on the error.

    except Exception as e:
        print(e)
‍‍

Re: Export raster attribute table into CSV using Python automation !

JohnWani — Thu, 08 Sep 2016 05:28:14 GMT

@Xander Bakker , the code runs fine for me and also generates .csv files but they contain only headers.

I am attaching a copy of *.csv files generated and some sample files.

Please help

Regards

John

Re: Export raster attribute table into CSV using Python automation !

XanderBakker — Sun, 12 Dec 2021 08:06:14 GMT

I changed the code to this and that resulted in csv files with data.

import arcpy, os
ws = r'D:\Xander\GeoNet\Raster2CSV\data'
outPath = r'D:\Xander\GeoNet\Raster2CSV\csv'
outExt = ".csv"
arcpy.env.workspace = ws
rasters = arcpy.ListRasters("*")
for raster in rasters:
    rasloc = os.path.join(ws, raster)
    fields = '*'
    try:
        flds = arcpy.ListFields(rasloc)
        header = ','.join([fld.name for fld in flds])
        if len(flds) != 0:
            outCSV = os.path.join(outPath, '{0}{1}'.format(raster, outExt))
            with open(outCSV,'w') as f:
                header += ',RasterName\n'
                f.write(header)
                curs = arcpy.SearchCursor(rasloc)
                for row in curs:
                    lst = [row.getValue(fld.name) for fld in flds]
                    lst.append(raster)
                    line = ','.join(str(a) for a in lst)
                    f.write(line + '\n')
    except Exception as e:
        print "Error processing", raster
        print "Error", e
        print "Is raster not integer or is there no attribute table?"
del row, curs‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

See files attached.

Re: Export raster attribute table into CSV using Python automation !

JohnWani — Thu, 08 Sep 2016 15:25:23 GMT

xander_bakker‌, Thanks a lot for the code, it worked perfectly.

Thanks again for saving my time.

Regards

John

Re: Export raster attribute table into CSV using Python automation !

BlakeTerhune — Thu, 08 Sep 2016 23:10:15 GMT

Is there an advantage to using the csv module over just creating a file with .csv extension and writing lines to it like you did in this example? Your way seems much simpler.

Re: Export raster attribute table into CSV using Python automation !

DanPatterson_Retired — Thu, 08 Sep 2016 23:15:54 GMT

the csv module handles way more cases and error checks to its toolset. If you have a well know data structure and you will be using it, then simple is good, should there be a chance that others may be doing it perhaps with poorly formed data, then the csv module is worth a look, just to save writing error checking.

Re: Export raster attribute table into CSV using Python automation !

GugaDB — Fri, 19 Feb 2021 15:52:25 GMT

Hello! First of all, sorry to revive an old post.

I'm also new to GIS, and needed something similar to this post, but I'm getting only one row of data from my rasters attribute tables.

The script which I'm replying to is creating the CSV files, generating two from four headers (creates objectid and rastername, but not "value" and "count", which are other columns from my attribute table) and writes just the first line of data from my rasters. I attached one example.

Also, it would be better for me to all this data got into one file, is that possible?

Could someone help?

Thanks!

Re: Export raster attribute table into CSV using Python automation !

GugaDB — Fri, 19 Feb 2021 17:04:44 GMT

Got the aswner in https://gis.stackexchange.com/questions/335604/exporting-the-attribute-tables-of-rasters-in-arcpy

Re: Export raster attribute table into CSV using Python automation !

Anonymous User — Fri, 19 Feb 2021 17:06:22 GMT

Looking at the docs for the search cursor, it says that raster fields are not supported:

"Raster fields are not supported."

What does your code look like? ... It would probably be best to create a new topic for your question.