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Asked: 2026-06-04T04:13:07+00:00

I’ve read in Tile E from NOAA/NGDC-GLOBE DEM ( tileinfo & metadata ) following

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I’ve read in Tile E from NOAA/NGDC-GLOBE DEM (tileinfo & metadata) following the steps at this blog.

I have a slightly different goal which is to find the highest point due W, SW, and NW of specific coordinates. So after I got matrix dem of the area, I created a referencing matrix:

Rdem=makerefmat('RasterSize',[6000 10800],'Latlim',[0 50],'Lonlim',[-180 -90]);

When I use ltln2val(dem,Rdem,40,-105) I get a value of -500 which indicates ocean. This location is in Colorado. Can someone please explain where I went wrong?

Thanks
Dominik

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1 Answer

  1. Editorial Team

    makerefmat is assuming the dem matrix is beginning at the bottom instead of the top which is common for many mapping functions. But because the Tile was read in using a generic function (not from the mapping toolbox), it acts like a normal matrix. makerefmat has an option to switch the direction in which rows are indexed for georeferencing. The proper syntax for Rdem is:

    Rdem=makerefmat('RasterSize',[6000 10800],'Latlim',[0 50],'Lonlim',[-180 -90],'ColumnsStartFrom','north');
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