topic Re: How to calculate relief with a radius of 2 km from DEM? in Esri Tutorials Questions

How to calculate relief with a radius of 2 km from DEM?

ABBS — Thu, 16 Jun 2022 14:51:50 GMT

Could someone provide me with a guide/suggestion/paper on how to generate/calculate the relief map of a region from DEM at a given distance (km) (i.e., radius in km)? The radius could be any value of choice. I desire to understand the spatial variation of relief in the region.

PS: Not the traditional hillshade map from ArcGIS

Re: How to calculate relief with a radius of 2 km from DEM?

AdenaSchutzberg1 — Thu, 16 Jun 2022 15:34:22 GMT

In what software? ArcGIS Online? ArcGIS Pro? Something else?

Re: How to calculate relief with a radius of 2 km from DEM?

ABBS — Fri, 17 Jun 2022 01:49:47 GMT

Any means/platform that could provide the solution including ArcMap is fine with me. Thanks.

Re: How to calculate relief with a radius of 2 km from DEM?

HeatherSmith — Fri, 17 Jun 2022 19:49:25 GMT

Hi @ABBS
I will assume that you already have a DEM layer. If you don't, you can extract one from the Esri terrain layer in ArcGIS Pro using the Export Raster pane.

I also assume you are looking to map a circular area, since you mentioned a radius. You first need a polygon layer representing this area. Here's how you can make one:

1. Insert Point Map Notes.

2. On the ribbon, on the Edit tab, click Create. Use the Create Features pane to draw one point in the middle of the area you want to map.

3. Save your edits. Clear the selection.

4. Open the Buffer geoprocessing tool. For Input Features, choose the Point Notes layer. For Distance, specify the radius you desire.

You now have a polygon representing your mapping area.

Next, you need to clip the elevation layer to the circle:

5. Open the Clip Raster geoprocessing tool. For Input Raster, choose the DEM. For Output Extent, choose your the new polygon layer. Check Use Input Features for Clipping Geometry.

Another new layer is added to your map. Turn off the other layers. You now have a circular DEM.

6. To turn the DEM into a hillshade (or other elevation visualization, like slope, contours, aspect), open the Raster Functions pane. Under Surface, click Hillshade.

7. For Raster, choose the newly clipped raster. Click Create new layer.

To learn more about visualizing elevation layers with raster functions, see this lesson: Illuminate terrain with a custom hillshade

Note that the results of raster functions are temporary. To make the results permanent, use the Copy Raster geoprocessing tool to save a copy.

Re: How to calculate relief with a radius of 2 km from DEM?

ABBS — Mon, 20 Jun 2022 01:45:00 GMT

Thank you @HeatherSmith for taking time for this elaborate guide. However, this does not solve the problem yet. In my case, I wish to quantitatively estimate the relief (local relief =maximum elevation- minimum elevation, over a given distance for a specific region). Indeed, this statement provides the mathematical approach to achieving the outcome but I do know how to manipulate either ArcGIS or others to achieve this. Please could you take a close look at the attached Figure?

The authors obtained the local relief by measuring the difference between minimum and maximum elevation within 10 km diameter (5km radius) windows around each pixel in the DEM. (This image is the Figure 5A of Thiede et al. (2009) , titled Erosional variability along the northwest Himalaya).

Take note that along the river, relief is highest whereas in the traditional hillshade, the elevation value will be lowest along the river as you have obtained above.

Thank you for your time and hopefully, I get a solution to this.

Re: How to calculate relief with a radius of 2 km from DEM?

Anonymous User — Sun, 26 Jun 2022 17:42:08 GMT

ABBS:

Your original question did not define the term 'relief'. From your subsequent clarification, I think you can use focal statistics tool with a circular neighborhood and 'range' statistics type to calculate this quantity.

Regards,

Jim TenBrink

spatial analyst team

Re: How to calculate relief with a radius of 2 km from DEM?

KeithAddison1 — Wed, 17 Apr 2024 20:24:43 GMT

I've come across this paper about local relief modeling:

https://www.researchgate.net/publication/289254539_Local_Relief_Model_LRM_Toolbox_for_ArcGIS_UPDATE_2016-05_-_new_download_link