topic Re: Join multiple tables derived from multiple raster datasets in ArcGIS Pro Questions

Join multiple tables derived from multiple raster datasets

GirijaKalyani — Tue, 11 Apr 2023 00:20:00 GMT

Hi all, I have multiple raster files (Daily data). All of them have a field "Area".

Now, I want to retrieve the sum of area of each daya (which I obviously can do using statistics).

But, I'm having to manually enter each day's data which is quite tedious for 20 years.

I want to save sum of area filed per day - for the entire year. The file names have got the information about day/month/year. Is there an easy way out I can add a filed that has name of the file, then join all these tables into one and export it and use for further analysis?

Re: Join multiple tables derived from multiple raster datasets

JohannesLindner — Tue, 11 Apr 2023 15:53:39 GMT

You can use a little Python.

raster_folder = "C:/data/rasters" output_folder = "" output_name = "AreaSumByDay" # create the output table table = arcpy.management.CreateTable(output_folder, output_name) arcpy.management.AddField(table, "Day", "TEXT") arcpy.management.AddField(table, "SumArea", "FLOAT") # start inserting values with arcpy.da.InsertCursor(table, ["Day", "SumArea"]) as cursor: # loop over the rasters in the folder arcpy.env.workspace = raster_folder for raster in arcpy.ListRasters(): # get the day from the raster name # for example, if your file names look like this: "bla_bla_date.tif" # you could do it like this: name = raster.split(".")[0] day = name.split("_")[-1] # get the sum of the area field raster_obj = arcpy.Raster(raster_folder + "/" + raster) sum_area = arcpy.RasterToNumPyArray(raster_obj).sum() # write into the table cursor.insertRow([day, sum_area])

Re: Join multiple tables derived from multiple raster datasets

GirijaKalyani — Sat, 22 Apr 2023 23:41:28 GMT

Dear Johannes Linder, thank you so much for getting back.

I have tested this multiple ways, but seems like the table is generated, but empty.

I get the following system error, also the table is created with the name area_sum_of_day, yet looks empty (like the second screenshot).

My file names are in style: asi-s3125-20030928-v5.4.tif or asi-AMSR2-s3125-20130101-v5.4.tif.

I want to split it around 10th character "asi-s3125-" in the first case and use 7 characters from there for the filename. Can you please provide me what is going wrong, it would save lots of time as there's heaps of data, and I have been spending a lot of time understanding these already.

Any help would be highly appreciated and greatly obliged