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DTM files
Posted: 27 Oct 2018 01:41
by martinvk
How do I use DTM files in TransDEM. Since they are the actual terrain without the trees and other stuff that distorts the elevation in DEM files, I thought I would try them.
From
https://open.canada.ca/data/en/dataset
I downloaded some of the DTM Geo TIF files.
When I try to open them in TransDEM, I get an error: ProjectedCSTypeGeoKey tag value unknown [unknown-2959]
Do I need to do something with them first before giving them the TransDEM?
Re: DTM files
Posted: 27 Oct 2018 11:05
by geophil
Unless there were dramatic changes in recent weeks, Canadian hi-res data is still in the very early stages, with only tiny areas covered so far. Therefore, I have not yet analysed their usage of GeoTIFF for this kind of DEM. TIFF and GeoTIFF have so many options and there is no real standard how to set these.
For the time being I recommend to use the 0.75 arc sec terrestrial data for Canadian projects. See my posts here how to identify, download and open the data:
https://forums.auran.com/trainz/showthr ... ost1689560
Re: DTM files
Posted: 27 Oct 2018 22:52
by martinvk
While it is true that only some of the urban areas, including the one I'm interested in, are covered. they would also provide a better ground contour than the normal DEM files. This is especially helpful in those urban areas with a lot of other clutter like high buildings that give a false impression of the local elevation.
So I'll continue using DEM as a source but look forward to the day that the DTM files can also be used.