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How to make DTM from DSM DEM Processing in QGIS Tutorial

GEO 2004

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Tutorial about how to make DTM (Digital Terrain Model) from DSM (Digital Surface Model) in QGIS using SAGA GIS Modules. This tutorial is intended to process low to mid resolution DSM/DEM like ASTER GDEM, SRTM, or ALOS 3D DEM 30 meter version.
Please be careful if you are intent to using this method, especially for the terrain slope setting. You must know exactly the general maximum slope (in percent) of your study area. This method probably wont works in fair level to a study area covering complex topographic features, but it is probably works best to flat to gentle terrain
This tutorial has been made using QGIS Software Version 3.2 Bonn. Why I am using this version? because this version has implemented an automatic SAGA GIS modules configuration, so you dont need to manually configure the SAGA Modules. Get QGIS for free at qgis.org.

Опубликовано:

24 июл 2018

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Комментарии : 37

@GEO2004 Год назад

one way to fix if the DTM result still have "holes" and "gaps" : ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-zTqb6E_kkNw.html

@sokhuonguon9251 4 года назад

Professional! Thank you so much

@TheManOnlyLegend 3 года назад

great video. Thanks for sharing. Good explanation too

@GEO2004 3 года назад

Glad it was helpful!

@AriMurdimanto 4 года назад

Thanks for sharing

@abiogenesis_arch Год назад

Thank you so much for this!!!

@GEO2004 Год назад

You are welcome

@callmeyourbae2859 5 лет назад

Can you share how to calculate the approx slope terrain? my DSM file is very vary, there is a hills and some buildings, when I use dtm filter, the removed object just the edge of the vegetations and the buildings that removed.

@GEO2004 5 лет назад

For your information, this method doesn't really works if you have very detail/large scale DSM, because the algorithm is only remove certain slope (according to the slope setting), and for detailed DSM, an object can have various slope ( building roofs and walls will have different slope value), so your result is just what the algorithm can do. If you have the DSM in point clouds format, you better using point clouds classification (global mapper has such tool) to remove the building and vegetation.

@nohayalgodisponible 5 лет назад

Gracias!!!!!!

@dariorestrepo3494 4 года назад

Good afternoon, I have a DSM product from Drone photo processing, I would appreciate if you know the parameters to process and build a Qgis DTM, I have practiced with the explanation of this video, but after the process there are gaps on the edges of the vegetation and the vegetation are still there with the height of their foliage and I don't know how to remove this part of the DSM English is translator, I speak Spanish, I hope my question is understandable, thank you very much

@GEO2004 4 года назад

As I already mentioned in the video or in another comments, this method will not perform very good for uav data, I guess you should stick to drone processing software like agisoft, menci, pix4d or any other. They have good point clouds classification tools that can be used for dtm generation

@dariorestrepo3494 4 года назад

@@GEO2004 Thank you very much, after asking you, I continued investigating other sources and I found this document that seems very successful for what I was looking for and very similar to the procedure that you use with a few more steps. "DEM Generation based en UAV Photogrammetric" www.scitepress.org/Papers/2016/59184/59184.pdf

@GEO2004 4 года назад

@@dariorestrepo3494 nice, thank you for the info, I am going to dig the document too

@dariorestrepo3494 4 года назад

@@GEO2004 thanks to you, your video warned me that it was possible

@semimonkey6144 5 лет назад

dtm filter it doesnt work :( I have the same qgis version. It just says de following message: The following layers were not generated correctly. You can see the "Registry Message Panel" in the main QGIS window to find more information about the execution of the algorithm.

@GEO2004 5 лет назад

have you try QGIS 3.4 madeira?, may be the updates will fix your problem, I also must admit that SAGA modules in QGIS is not always perform stable. Sometimes it generate random error, may be you can try using other kind of DSM, just to make sure that the problem lies on the software and not your data

@semimonkey6144 5 лет назад

@@GEO2004 is it necesarry to give previously the ground class and non-ground class to dsm? I thing that my dsm have not that information.

@GEO2004 5 лет назад

@@semimonkey6144 nope, the algorithm just use slope as the parameter

@chuckmiller3075 4 года назад

@@GEO2004 I was having the same problem, but just pulled down 3.10.2 and now the dtm filter is working again.

@zikoman7495 Год назад

I already have dtm files from surpac software how can I import it to qgis It is important for me thanks in advance

@GEO2004 Год назад

If surpac can export the dem into geo tiff format, you are good to go,

@mohama7551 Год назад

Doctor, please tell me how to convert qgis hackable b spectral band satellite visuals into a format. gpr. Or ert, of course, after I make the corrections, so that I can make models under the surface to study the structures and remains of ancient buildings buried under the sands using the Qgis program. Please tell me, I specialize in the study of civilizations and antiquities

@GEO2004 Год назад

Sorry, I didnt understand your question,

@mohama7551 Год назад

@@GEO2004 How do I display Landsat images with items 10 and 11 refractories, laos, or others in gpr format. With the Qgis program, I mean, in a way that I know the location of the remains of archaeological buildings buried under the surface of the earth

@GEO2004 Год назад

I have told you, landsat cant penetrate the earth surface, no matter which bands are used,

@mohama7551 Год назад

@@GEO2004 What images can do that

@GEO2004 Год назад

I dont know, I am not an underground mapping expert, sorry.

@sayyadsahilahmed321 3 года назад

How can we find terrain slope percentage? Like you inserted this as 5%, how you got this number? Anyone please answer!

@GEO2004 3 года назад

that is inferred from my general knowledge about the terrain of study area (not too scientifically sounding thru), it was based on deduction, if you had better or more precise way to infer the slope, that would be better.

@sayyadsahilahmed321 3 года назад

@@GEO2004 I got your point, but what I need is scientific method to find that particular number for my study area. I generated slope raster in Qgis but it was in range between 900 to 2000000 (approx). What will be the percentage slope here then.

@GEO2004 3 года назад

What?! Is there any flat terrain in your study area? Seems your calculation is wrong. I rarely using qgis these days, but I think qgis should be able to calculate slope in percent rise.

@sayyadsahilahmed321 3 года назад

@@GEO2004I checked that percentage checkbox. Yeah something is wrong. Can I get your mail address to share screenshots with you? Thanks

@GEO2004 3 года назад

mappingsince2004@gmail.com