I've updated my previous work on Administration numbers (see this post). I added some functionality wherein I now have an R shinyApp up and running that will change the plot to be a Cabinet Level agency of your choice.
Check it out and lemme know what you think!
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As a PhD student in Tectonic Geomorphology, I spend a lot of time analyzing topography. One of the tools I have often used is TopoToolBox. This Matlab native toolbox has any different suites of topographic analysis and is specifically geared to analyze river networks. One analysis that I have made use of that is not built into TopoToolBox is comparing the hypsometry (or distribution of elevations) to the slope and relief in each elevation band. I describe herein a tool I developed to approach such a problem, built to work within the TTB environment. The long profile of this stream reveals a sharp change in gradient, or knickpoint. This knickpoint could be a transient signal, transmitting information of base-level lowering to the catchment above. This means that the slopes above the knickpoint are unaware of the lowering-event the bottom portion of the catchment is feeling. My new function GridCompare, which takes the following inputs:
Example code: load DEM.mat %Load premade example DEM (from above illustration) gridcompare(DEMoc); % run grid compare. The result is below: Plot 1: Hypsometry (blue bars) vs the mean slope (red line) and σ-1 of slope (dashed line) in each elevation band. The first thing to note is that there's an accumulation of topography at higher elevation >1400 m. Secondly, this elevation band has much lower slopes than other elevation bands <15° average slopes compared with 25-35° slopes below this elevation Plot 2: Relief v Elevation. Relief is calculated in a 500 m moving window across the grid. Similar to Plot 1, the higher elevation with greater area has lower relief. To some extent you may expect this trend in non-glaciated landscapes where as you approach the tops of mountains, there is less and less available topography for relief! But the correlation to the higher elevation region is remarkable. This tool is available at my Github Page with this example.
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AuthorI started learning how to program in High School. For a while now, I've been learning how to effectively use Matlab and R for data analysis and visualization. I will put the codes I've benchmarked and just interesting plots I make here. Archives
September 2019
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