Obtain an extract of Terrain

[KatyAppleton1]

I'm teaching GIS in a university environment to students who use ArcGIS Pro and have access to a large amount of local storage. I had hoped they could use the Living Atlas Terrain layer as a source within Pro to obtain a DEM for an country of their choice, for further processing using Spatial Analyst and integration with other locally-stored data. They already have access to a polygon covering their chosen country for masking purposes.

The Terrain layer I mean, for clarity, is: https://www.arcgis.com/home/item.html?id=58a541efc59545e6b7137f961d7de883

The layer information states that "For analyses using ArcGIS Desktop, you can filter a dataset, specify the projection, extent and cell size using the Make Image Server Layer geoprocessing tool."
We have found that there is a limit to this process (with this layer), of 5000 rows x 5000 columns. Is there an alternative workflow to be able to obtain a larger dataset from this layer for analysis? Currently we have decided to download tiles from CGIAR and mosaic/extract for the desired country, but I wanted to check I am not missing a more seamless solution from Living Atlas.

It would also be useful to state this limitation clearly on the layer description.

[RajinderNagi · Accepted solution]

Hi KatyAppleton1, Thanks for the note. There is a limit on export/analysis extent on this global service as you mentioned, which is clearly stated on Terrain item page near the bottom and we can elevate that information.

“This layer allows query, identify, and export image requests. The layer is restricted to a 5,000 x 5,000 pixel limit in a single request.”

The Terrain service is comprised of global sources of various resolution (see Elevation Coverage Map) and depending upon the analysis need, one can filter a particular resolution. The limit of 5000 rows x 5000 columns means that if the resolution chosen for analysis is 10m, then the analysis limit would translate to 50,000 m x 50,000 m. As you are interested in CGIAR SRTM, which is ~90m, the maximum analysis limit would be 450 km x 450 km.

You can check out UC presentation below, which covers performing analysis with Terrain layer in desktop environment. Analysis with ArcGIS Pro section is from 12:30 - 26:00 minutes in the video.

https://mediaspace.esri.com/media/t/1_ofro14se

For North America, we have USGS 1 arcsec (~30m), which has higher limit of 24000 x 24000 if that’s of interest. There is also GMTED 7.5 arc sec (~250m) available in the Living Atlas

There are many other elevation layers available on Living Atlas from various authoritative providers that you can check out: https://livingatlas.arcgis.com/en/browse/#d=2&categories=Elevation+and+Bathymetry&type=layers

Hope this helps!

[KatyAppleton1]

Thanks, apologies that we missed that restriction at the bottom - I was looking at the Analysis section. So the resolution (that the 5000 limit refers to) would be what is set in the Make Image Server Layer dialog and not the native resolution of the area in the Terrain dataset?

And I appreciate the link, I found mention of the same UC presentation on an older thread but the link provided was expired. We are still learning about making best use of Living Atlas materials so it will be very helpful!

[RajinderNagi]

KatyAppleton1, You can specify the resolution of a particular dataset in the 'Make Image Server Layer'tool and it will create temp layer based on that.  The service is showing cell size of the finest dataset in the collection and you would need to change that during the creation of temp layer. I would suggest checking out the analysis part in the video.