MATLAB: Unable to read DEM file with GTOPO30s

demgtopo30Mapping Toolbox

i am trying to read GTOPO30 data I downloaded from USGS https://earthexplorer.usgs.gov/.

I selected a region in So. California with latlim [34 36], lonlim [-120 -118]. When I try reading the DEM file I get an error:

The GTOPO30 directory, 'C:\Documents\MATLAB\gt30w140n40_dem/', does not contain data for the specified latitude longitude limits.

But I am pretty sure I have the correct dem tile with the correct latitude longitude limits.

In fact gtopo30s([34 36],[-120 -118]) returns the correct tile name w140n40. Any help would be greatly appreciated.

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MATLAB: Error Reading a DEM file using “gtopo30” function of the Mapping Toolbox

Start by downloading the "W140N40" tile from here:

https://dds.cr.usgs.gov/srtm/version2_1/SRTM30/w140n40/

Note: Make sure to download "w140n40.hdr.zip" and "w140n40.dmw.zip" and place the extracted HDR and DEM in your MATLAB current folder.

Execute the below commands to get the map of the region:

[Z,refvec] = gtopo30('W140N40',1,[34 36],[-120 -118]);
figure
usamap(Z,refvec);
geoshow(Z,refvec,'DisplayType','surface');
demcmap(Z);

MATLAB: What directory structure does GTOPO30 need for reading in tile directories of topographical data

This enhancement has been made for Release 14 SP1 (R14SP1). For previous product releases, read below for any possible workarounds:

The following describes the directory structure you are looking for. When you download the data from an FTP site, each file needs to be extracted into a tile directory with the name of the compressed files. For example, "e060n40.tar.gz" needs to be extracted into a tile directory named "E060N40". Additionally, all of the tile directories need to be located in the same parent tile directory.

Note the syntax required for the directory path argument when using GTOPO30. The argument requires that the path ends in a slash.

The following is an example that uses GTOPO30 to read files from a directory structure:

latlim = [30 45]; lonlim = [60 90];
gt30files = gtopo30s(latlim , lonlim)
 gt30files = 
     'e060n90'
     'e060n40'
% Using:< ftp://edcftp.cr.usgs.gov/pub/data/gtopo30/global/>
% Download "e060n90.tar.gz" into a tile directory named "E060N90".
% Download "e060n40.tar.gz" into a tile directory named "E060N40".
% Extract the data files into their directories.
% To extract in UNIX, e.g. (assuming you have access to gzip and tar):
%     gzip -d e060n40.tar.gz
%     tar -xf e060n40.tar
% To extract on Windows, use a decompression application such as WinZip. 
% *** Note: If extracting on Windows, be sure NOT to use "TAR file smart CR/LF conversion".
%     WinZip allows you to DESELECT this option under Options->Configuration...->Miscellaneous->Other.
% To save disk space, you can delete the tar file.
% Change directories into the parent tile directory of "E060N40".
p = [pwd '/'];          % Store the path to the parent tile directory while appending a "/"
dir(p)
    .        ..       E060N40  E060N90
[map,refvec] = gtopo30(p,5,latlim,lonlim);
axesm mercator
meshm(map,refvec)

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MATLAB: Error Reading a DEM file using “gtopo30” function of the Mapping Toolbox

MATLAB: What directory structure does GTOPO30 need for reading in tile directories of topographical data

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