Raster cell size changes when exporting data?

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07-21-2021 08:26 AM
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EmmaCowan
New Contributor

Hi there,

I am looking at land classification data from the Copernicus satellite and clipping it to the extent of Wales, I have different layers for permanent water, grasslands, urban/impervious and tree cover density. The standard resolution I am using for my data is 20m cell size. As all my data covers the same area, the raster size is 9308 columns and 11496 rows for every layer in Wales. For my urban raster layer, this appears as the raster size on the properties tab, however when it comes to exporting the data the 'Export Raster' tab shows these numbers of columns and rows to be completely different? The number of columns comes out as 13066 and rows as 14498 when it comes to exporting the raster.

I am confused why the column and rows have changed even though no further analysis has been done. It is important to my project that these remain the same as I have to process the land classification data in R studio in order to determine if the area (ha) of certain land classes has been affected throughout time.

I have spoke to my tutor and we are both a bit unsure for this change in raster size when it comes to exporting as a tiff. 

Any suggestions would be appreciated! Cheers :) 

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DanPatterson
MVP Esteemed Contributor

Cell Size (Environment setting)—ArcGIS Pro | Documentation

Cell Size Projection Method (Environment setting)—ArcGIS Pro | Documentation

Use tools in arctoolbox to process rasters.

Tools have environment tabs and settings you can access.  The second link is an important one when considering what can happen if cell size, snap raster and other issues (like projections during copying).

Consider your situation in light of those links then get back with further questions


... sort of retired...
curtvprice
MVP Esteemed Contributor

 It's important to look all the options when doing an export to make sure you get what you want! This layer you are working with an ArcGIS image layer, which resampled on the fly when displaying (for performance reasons, all the data is not downloaded) - so to download full resolution you need to specify the cell size you want in the Export Raster dialog.

I am not sure the environment settings that Dan mentioned will work with the layer export dialog.

DanPatterson
MVP Esteemed Contributor

No Curtis... that is why I said to use ArcToolbox tools (eg, copyraster), where you have full environment control with no substitutions or defaults


... sort of retired...
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curtvprice
MVP Esteemed Contributor

Dan, we'll have to agree to disagree on this one, the right click export functionality (which is sounds like was being used here by the OP) is quite handy and useful. Any interface though has parameters you need to pay attention to in order to get what you want though!

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