Multi-scale topographic position visualizations

I thought that people would enjoy this beautiful map that I have been working on this holiday season. It is a visualization derived from an SRTM digital elevation model based on a multi-scale topographic position analysis. This is one that you really have to click to enlarge to fully appreciate. I have spent hours lost in the detailed galactic colouring of this map!

This beautiful map of eastern Canada and the US was made with Whitebox GAT’s newest multi-scale topographic position tools. (click on image to enlarge)

This beautiful map of eastern Canada and the US was made with Whitebox GAT’s newest multi-scale topographic position tools. (click on image to enlarge)

I’m working on a paper right now in which I describe a new form of local topographic position analysis and the map above is one of the resulting visualizations. It shows prominent features at the small (blue channel), medium (green channel), and large (red channel) scales. A prominent feature is one that is either significantly above or below the surrounding landscape at the scale of interest. There’s actually a fair amount of analysis (and coding!) involved but if you’re really interested and can’t wait for me to finish the paper, send me an email. Here is a similar map but covering parts of British Columbia, Canada:

Mulit-scale topographic position for British Columbia, Canada (click to enlarge)

Mulit-scale topographic position for British Columbia, Canada (click to enlarge)

And this is the multi-scale topographic position map derived from SRTM data for the Northern Territory of Australia:

Topographic position map of the Northern Territory, Australia (click to enlarge)

Topographic position map of the Northern Territory, Australia (click to enlarge)

Personally, I think that these visualizations are remarkable for their ability to characterize the structure of the surface geology of a region but I’m sure that there are many other interesting applications as well. Interpreting the images takes a bit of experience but the following interpretation key can help:

Interpretation Key

Interpretation Key

Leave your comments below and, as always, best wishes and happy geoprocessing.

****UPDATE (May 27, 2015)****

This work was eventually written up as a manuscript and has recently been accepted for publication by the journal Geomorphology. The citation is:

Lindsay, J.B., Cockburn, J.M.H., and Russell, H.A.J. In press. ‘An integral image approach to performing multi-scale topographic position analysis’ Geomorphology, 245, DOI: 10.1016/j.geomorph.2015.05.025.

This article can be downloaded for free until July 18, 2015 from the following link:

http://authors.elsevier.com/a/1R6Uf,3sl3TsZi

And the submitted draft is available here.

11 thoughts on “Multi-scale topographic position visualizations

    • Hi Qiusheng Wu, Yes the plan is to incorporate the method for performing this multi-scale topographic position analysis and these visualizations in a future release of Whitebox GAT.

    • Hi William,

      I’m glad that you like it. The script for performing multi-scale topographic position analysis is already in the Whitebox source code repository (https://code.google.com/p/whitebox-geospatial-analysis-tools/source/browse/trunk/WhiteboxGIS/resources/plugins/Scripts/MultiscaleElevationResidualIndex.groovy). Although it won’t be public until the next official release (hopefully coming soon) you can get an early preview simply by ‘Update Scripts From Repository’ under the Tools menu, or by copying and pasting the code in the link above into the Scripter and saving the file. The part that is still missing is the small script that I use to combine three of the output rasters of the multi-scale TP tool to create the colour composite. I submitted the paper describing the method for review a little while ago. I’ll certainly finish off making the tools available before the paper is accepted and eventually published. In the meantime, if you like, email me and I’ll send you a copy of the manuscript. I’d really enjoy seeing some of the beautiful images that other people may create using this technique for other parts of the world.

  1. benjamin says:

    Hi John,

    I liked you article a lot and I am trying to test it for the purpose of archaeological interpretation of lidar derived DEM’s. However, for the life of me I cannot find the “Create Multi-scale Topographic Position Image” in the latest Whitebox GAT 3.2 Iguazu. Is it me or do we have to exhibit just a little patience?

    • Hi Ben,

      Please feel free to email me for further details as needed but there are two tools that you need to use. The first is called Maximum Elevation Deviation and can be found in the Terrain Analysis toolbox. You will need to run this tool three times, for three different scale ranges. Once you’ve created three DEVmax rasters for your desired scale ranges, you need to combine them into one colour composite image using the a script called ‘customRGBscript’. To find this script, you’ll need to open the Whitebox Scripter and you should be able to find it listed from there. I haven’t yet converted this script into a proper Whitebox plugin tool so you’ll need to hard-code in your file names corresponding to the three DEVmax rasters that you’ve created.

      Regards,

      John

      • Anonymous says:

        Hi John,

        sorry for the late reply. I merged DEVmax rasters as RGB values in an external tool. As I mentioned, I was testing the tool for the purpose of archaeological interpretation of lidar derived DEM’s and the results are excellent. Obviously it is a specific tool for a specific task, but very useful! Are you interested in co-writing up an article (smth. like “Arcaeological application of MSTPV)?

      • Hello,

        This sounds like a wonderful idea. I’ve been interested in geoarcheology applications but have never had the opportunity to do research in the field. Send me an email and let’s talk about the application that you’ve used the MSTPV for.

        Cheers,

        John

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