Digital Elevation Models in GIS (theory) - updated

This video presents what digital elevation models (DEM) are and how they are used in GIS. New in this updated lecture: 2.5D animations, examples from IHE Delft fieldwork area near Digne-les-Bain, France and better illustrations.
IHE Delft OpenCourseWare can be found at www.gisopencourseware.org
For an overview of our GIS courses and info on tailor made trainings and advise see our folder: www.un-ihe.org/sites/default/...
More information about the book "QGIS for Hydrological Applications - Recipes for Catchment Hydrology and Water Management" by Kurt Menke and Hans van der Kwast can be found at the website of Locate Press: www.locatepress.com/hyd
IHE Delft and Nieuwland Geoinformatie offer an online course. It includes support from experienced trainers and you'll get the official QGIS certificate after completion. More info at: www.learning-gis.com
Subscribe to the KZbin Channel for updates!
0:00 Introduction
1:37 DEM acquisition
4:28 Use of DEMs
6:01 Example French Alpes
7:27 Hillshade
8:09 Contour lines
8:52 2.5 D / 3D
9:15 Drape orthophoto over DEM
9:34 Slope
9:56 Aspect
10:34 Viewshed
10:46 Topographic Wetness Index
11:08 Transects (profile tool)
#QGIS #QGISHydro

[@macegamma431]

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

[@kyawzayertint1255]

Thanks for the information

[@baselabusaleh3194]

Thank you Hans

[@thessalonia504]

nice video. thank you!

[@sureshkotwal656]

Sir very useful video thanks

[@nyashamarty5602]

Thanks... For the help

[@eivindkofod1774]

Thanks from Borneo

[@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?

[@nuclearant9523]

Thanks!

[@mohamedelfeki3975]

Thank you

[@aureliopds]

Great!

[@survfitkastevebilshakkafge4291]

Good one

[@Megha24.]

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

[@peterokitoi7757]

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

[@cilbup]

thank u teacher

[@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!

[@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.

[@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.

[@sabinjoshi007]

👍👍