Digital Elevation Models in GIS (theory) - updated

[@macegamma431]

SO good. i wish i was given a chance to be lectured by you in my university days. concise

[@DiegoAndresAlvarezMarin]

Great videos. I have a question. In minute 4:00 you mention several methods for DEM adquisition (DGPS measurements, Stereo photogrammetry, LIDAR, Radar interferometry). Which is the precision/accuracy of each one of them?

[@jeroenarends5234]

Very informative videos, thank you. I was wondering about that dial in the hill shade example around the 7:31 mark. Is that part of QGIS itself or does it come with a plugin? Another question I have and, correct me if I am wrong, regards the draping of a satellite image such as Sentinel 2 over a DEM. S2 is 10 meter cell size and a typical SRTM DEM would be 1 arcsec or roughly 30 meters cell size. If you drape a S2 over such a DEM, the result would look rather grainy in 3D (or rather 2.5D). Instead, I often reproject and resize the DEM to 10 meter cell size and then drape the S2 over that. It looks much finer but of course it is only for illustration purposes because the cell values in the DEM would not be accurate. Am I right in my assumptions? I do this mostly in SAGA btw. Thank you.

[@HansvanderKwast]

The dial is part of the QGIS hillshade renderer which is available in recent versions. So no plugin needed. I don't think the resampling is needed, the 3D view will take care of that. It will not make a difference, because it will uniformly cut the pixels. A better way is to use the resampling option in the Layer styling panel and put it on bilinear or cubic.

[@baselabusaleh3194]

Thank you Hans

[@pranaxedm888]

Great work man. I just wanted to know if you also have tutorials about pure river hydraulics apart from the gis part. Thank you.

[@HansvanderKwast]

Thanks. Unfortunately I don't have tutorials on hydraulics.

[@pranaxedm888]

@@HansvanderKwast no issues.keep doing the great work. This video has let me understand the basics of DTM and it's uses,also all the other parts explained regarding DEM and GIS software has better improved my knowledge about this field. Thank you.

[@Megha24.]

Thanks for the video, it really helped me to understand the topic.

[@nickl4971]

Thanks for the video! May I ask why the light source for hillshading is commonly placed at NW? Are there cases when different placement of the light source is preferable?

[@HansvanderKwast]

Our brains are intepreting relief correctly if the light source is in the NW, so that's just for visualisation. If you want to model real shades, for example for planning solar panels or energy balance modelling, you should adjust the hillshading according to the sun elevation and angle, which is possible in the algorithms.

[@nickl4971]

@@HansvanderKwast Got it, thanks!

[@kyawzayertint1255]

Thanks for the information

[@eivindkofod1774]

Thanks from Borneo

[@sureshkotwal656]

Sir very useful video thanks

[@thessalonia504]

nice video. thank you!

[@peterokitoi7757]

is it possible to transfer dem terrain and shape files from qgis to hec-hms

[@mohamedelfeki3975]

Thank you

[@nyashamarty5602]

Thanks... For the help

[@nuclearant9523]

Thanks!

[@aureliopds]

Great!

[@survfitkastevebilshakkafge4291]

Good one

[@cilbup]

thank u teacher

[@sabinjoshi007]

👍👍