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Is it possible to split a raster by a series of attributes in a column?

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03-03-2023 05:45 AM
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QuintinChua
New Contributor II

Running ArcGIS Pro 3.0.3 

Hello! I'm new to GIS as a whole and I am trying to use it for some applications in my studies at university. Specifically I want to track the density of people and built infrastructure within countries over time.    

I've come across a dataset which seems to harmonize national boundaries with coastlines exceptionally well. The only issue is that the information per country is stored in multiple polygons.

QuintinChua_0-1677850181479.png

On a country per country basis, this is not a problem. As I can select by attribute and only clip the polygons necessary to the global raster.

QuintinChua_1-1677850532236.png

The problem arises when I would like to repeat this process for every country in the data, and then again through time. Would there be anyway for me to iterate over the ISO name column in order for me to split and extract the data that way? or is there perhaps a work around where I could combine the polygons on a national level and then split the global dataset?

Any help could be much appreciated! My apologies if this is a basic question, I'm just dipping my feet in GIS. 

Additional Info!

The data I'm using for the polygons comes from here: https://hub.arcgis.com/datasets/WorldPop::national-boundaries-1km/about

and the population and build density data originates from: https://ghsl.jrc.ec.europa.eu/download.php

 

 

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DavidPike
MVP Frequent Contributor

https://pro.arcgis.com/en/pro-app/latest/tool-reference/data-management/dissolve.htm

dissolve field = ISO

multipart = depends on your requirement, possibly multi_part

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4 Replies
DavidPike
MVP Frequent Contributor

https://pro.arcgis.com/en/pro-app/latest/tool-reference/data-management/dissolve.htm

dissolve field = ISO

multipart = depends on your requirement, possibly multi_part

QuintinChua
New Contributor II

Hello, @DavidPike ! Thank you so much for your help.

I was able to dissolve the data into their national level divisions.

QuintinChua_2-1677981731833.png

But when I tied to use the split raster tool under the following conditions:

Split Raster
=====================
Parameters

Input Raster Build Layer 2022\GHS_BUILT_V_2020_Normalized
Output Folder ***\Test
Output Base Name GHS_BUILT_V_2020_Normalized
Split Method POLYGON_FEATURES
Output Format TIFF
Resampling Technique NEAREST
Number of Output Rasters 1 1
Size of Output Rasters 2048 2048
Overlap 0
Units for Output Raster Size and Overlap PIXELS
Cell Size
Lower left origin
Split Polygon Feature Class ppp_1k_mask_Dissolve
Clip Type NONE
Template Extent DEFAULT
NoData Value
Updated Folder ***\Test
=====================
Messages

Start Time: Sunday, March 5, 2023 1:12:19 AM
Succeeded at Sunday, March 5, 2023 7:03:04 AM (Elapsed Time: 5 hours 50 minutes 44 seconds)

The task did complete successfully though the resulting folder was empty.

QuintinChua_3-1677981860034.png

Was there an issue with the way that I choose to split the global raster? or is there perhaps another method that I should use? 

Thank you so much again for your help and patience!

 

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DavidPike
MVP Frequent Contributor

I've not actually used the split raster tool.  It may not be ideal even if it does work as it just suffixes a sequential number to the output raster.  I can see some options being set such as pixel size - did you set those or are they defaults?  I'd suggest leaving everything optional as blank and just specifying split type and split polygon options.

There's a post here (arcmap but the principle is the same) for how I'd prefer to control the output names by iterating through the polygon features in an iterator/for loops and either 'clip' or 'extract by mask'.  As the post states please be aware of cell size and snap raster environments (look up what they are and why they are important also).

 

https://gis.stackexchange.com/questions/382395/splitting-raster-by-polygons-and-defining-output-name...

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HannahHyatt
New Contributor II

I realize I'm late to the party here, but you could use the Extract by Attribute tool: https://pro.arcgis.com/en/pro-app/latest/tool-reference/spatial-analyst/extract-by-attributes.htm

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