Blender, QGIS & Digital Elevation Maps

[@JuanFox]

In QGIS, the difference in brightness is caused by the max and min values in the color ramp for.each layer. Each color is applied from black to red (for example) being red the highest value of that layer and being black the lowest. If the value range is not the same, the color won't either. To solve it, you have to merge the layers beforehand or set the same max and min values for each.

[@Mark_Alloway]

Thank you for that explanation. I'll give that at try the next time I make a terrain.

[@marcospieras5626]

Nice video! Which workstation do you recommend to work with Blender in this kind of project ? Thank you!

[@Mark_Alloway]

I'm not a hardware expert. I use an alienware gaming PC for my work. it seems to hold up pretty well.

[@BhadranRP]

Excellent!!!!

[@cauzin8240]

incredible, is there a way to import the finished work into unreal engine?

[@Mark_Alloway]

I'm sorry, but I don't know anything about UE. I've never used it.

[@institutderecherchesurlesf3655]

Hi, great video. I'm a pretty decent cartographer, but you completely lost me when you get in the Blender part. Is there a Blender tutorial you could recommend that would help?

[@Mark_Alloway]

There are thousands of good introductory videos on KZbin. I would search KZbin for "Blender Introduction" or you could start where many of us started - Andrew Price's videos (Blender Guru). He's an instructional icon within the Blender community. (kzbin.info)

[@CatherineScott1]

I finally got it, but can you put a screen shot of just the nodes in Blender it's hard to see what's connected in the video

[@Mark_Alloway]

I've uploaded the project file to Blend Swap so anybody can use it. It may take a few days for the upload to be accepted by Blend Swap. I'll add a link in the KZbin description once the file has been accepted. I had to reduce the size of some of the image files in order to pack them into a .Blend file. The renders still look pretty good, even with the smaller files. In the mean time, you can try to download it, but I'm not sure you can until it has been accepted. www.blendswap.com/blend/30437

[@Mark_Alloway]

Blend Swap file is available now: blendswap.com/blend/30437

[@FoundAndExplained]

Gonna be super useful for me! Thanks mate! Also still got that offer out for you if you ever wanted to do some consulting for me :) I'd love to pick your brain on my projects!

[@Mark_Alloway]

I'm glad it's useful. I'm happy to answer questions, but consulting isn't my thing. I appreciate the offer!

[@jcjensenllc]

you fail to mention USGS requires an account login to download the data.

[@Mark_Alloway]

Yes, you are correct. I did that so long ago that it slipped my mind. Thanks for letting others know.

[@genom26]

I would like to express my gratitude for the well-crafted lesson. I am very thankful for the provided material. It was extremely helpful and informative

[@Mark_Alloway]

Thank you for leaving such a nice comment. I'm glad it was helpful.

[@lokisinary_play]

Why downloading process of data files from usgs is so bad. 😢

[@Mark_Alloway]

They're really big files. Unfortunately it can take some time to download them.

[@CDANODC]

Great video, thanks for taking the time to make it. Made life easier

[@CatherineScott1]

Following the video instructions I started a new project to see if I can get through it, now I'm having an issue I set the B2, B3, and B4 in their respective colors when I change the 'Blending Mode' in Layer Rendering the image disappears instead of blending. BTW, when the project becomes available on Blender swap I will definitely get it thanks for sharing.

[@Mark_Alloway]

Are you changing the blend mode for all three layers? Red (the bottom layer) should not be changed. By default, it should be set to "NORMAL". Blue & Green should be set to "SCREEN".

[@akhila8581]

@@Mark_Alloway thanks maan

[@philallsopp42]

Really very helpful. Nicely done. Great video tutorial

[@fletchmane6075]

Is it possible to transfer these to Unreal 5?

[@Mark_Alloway]

I wish I could help, but I've never used Unreal.

[@BillKermanKSP]

Painting in the ocean by hand is very time consuming, there are highly detailed datasets of shoreline, which can be used to generate a water factor map

[@Mark_Alloway]

I totally agree, but I couldn't find a way to use that data. Can you point me in the right direction? Thanks.

[@BillKermanKSP]

@@Mark_Alloway What was the problem?

[@Mark_Alloway]

@@BillKermanKSP I never found a way to isolate water. I suspected the data was there, but I just don't know enough about QGIS to extract a water mask.

[@BillKermanKSP]

@@Mark_Alloway It's not included in the satellite imagery, there are some good datasets though (e.g. GSHHG). They're rather large for a shapefile but easy to use in QGIS (just make sure you use the highest quality layer)

[@Mark_Alloway]

@@BillKermanKSP Thank you for sharing that with me and everyone else. I'll have to look into that. I appreciate the tip.

[@prestyns888]

Hi Mark, you can use NDWI for a water mask. (Green - NIR) / (Green + NIR) in raster calculator. Then, you can use the identify features tool to identify the number for water vs land. Water is usually above 0.2. So 0.2-1.0 can be classified as water and

[@prestyns888]

Then you can use the QGIS color wheel to increase transparency for the land. Not a photoshop expert, but then I assume you can use that water mask as a new layer into photoshop that can be put as an overlay on top of the Landsat layer.

[@Mark_Alloway]

@@prestyns888 Thank you for this detailed feedback. It will be very useful to me and others who use QGIS. I really appreciate it.

[@prestyns888]

​@@Mark_Alloway Cheers mate. Additionally, you can use the SCP Plugin to create a stacked raster. This will load all bands into one raster layer. Go to SCP dropdown -> Select Band Set -> Load all your bands in the multiband set -> Select 'create stacked raster' on the bottom of the popup -> hit run. Then, once it's run, you can go into your symbology from layers, and if you wanted to create the natural Color effect, select bands 4-3-2 for an RBG image. Less of a hassle in photoshop as well! Hope this also helps.

[@Mark_Alloway]

@@prestyns888 That sounds promising, but well beyond my current understanding of QGIS. I will definitely give it a try the next time I make a terrain. Thanks again for the feedback. It helps me and everybody else who happens upon this video.

[@elusiveme3279]

thank you from japan

[@theforest8882]

Can I just do this in qgis?

[@Mark_Alloway]

I'm not sure what you mean by "this". Are you referring to the stuff I did in Photoshop or something else?

[@Pestreza]

I tried to like more than 10 times during your class

[@Mark_Alloway]

Thank you. That's very kind of you.

[@domfel2123]

I would rather download from Qgis directly and merging tiles

[@Mark_Alloway]

What do you mean?

[@huangyan-chen724]

Really great tutorial. Did you consider using NDVI or other indices to create the water mask?

[@Mark_Alloway]

I know very little about QGIS, so the approach I took to hand painting the water masks was a result of me not being able to figure out a more elegant solution. I wasn't happy with it, but it works. I had never heard of NDVI before, but I looked it up and it looks interesting. Is there a way to calculate NDVI in QGIS? If not, how would you suggest creating the water maps? Thanks for the tip/feedback. I always like learning new things.

[@mediaeducativa3339]

This is one of the best videos on the topic and I've watched some.

[@Mark_Alloway]

Thanks for leaving the comment. Did you resolve the issue you had with white areas on the DEMs?

[@NeoGaara3]

What a nice video. I've been trying several similar workflows and yours has some really interesting parts and it's well explained. Thank you!

[@ehsandadvar5831]

Hello where are nodes ? I did not understand

[@Mark_Alloway]

Do you mean the nodes in Blender? They're all part of the material used to texture the ground material. You have to go into Blender's Shader Editor to see them. Does this help?

[@armandadvar6462]

@@Mark_Alloway No I mean the nodes that apeared on your scene

[@Mark_Alloway]

@@armandadvar6462 I'm sorry, but I still don't know which nodes you're talking about. Can you post the video timestamp that shows what you are talking about? Thanks

[@ZhongyaLiu]

very useful! thank you for this video very much!

[@benmissimer]

Excellent!

[@Timeless_TRUTHS_Geo]

Great video, Thanks for taking the time to make it. 🥰🥰🥰

[@Mark_Alloway]

Glad it was helpful.

[@byShawnPark]

Awesome! Thanks so much for creating this tutorial.

[@pinyang8782]

I do not have the crop option, where can i enable it?

[@Mark_Alloway]

Are you saying the "new shapefile layer" button is not enabled? (kzbin.info/www/bejne/Y6bFdaSOj9mXgKc)

[@toonverberg1313]

A very good in-depth video. Thanks a lot, Mark!

[@quintin7203]

Great videos!

[@lmydawson5885]

Where can i get a displacement of the continent

[@Mark_Alloway]

I'm not aware of a single map that would cover the entire continent, but you can make your own. Open Earth Explorer and make the entire continent your "area of interest". Download the individual DEM files for the area you want to model. Bring all those maps into QGIS and merge them into a single virtual map. (See the section of this video where I talk about creating Virtual Raster images: kzbin.info/www/bejne/Y6bFdaSOj9mXgKc). The resulting file could be REALLY big, especially if you export high-resolution files from QGIS.

[@lmydawson5885]

@@Mark_Alloway thank you very much

[@pinyang8782]

Mine B2, 3, 4 and 8 is different but when i set the height map to red and apply, it doesnt show any red, no changes. Any advice?

[@pinyang8782]

not even blue

[@Mark_Alloway]

@@pinyang8782 Bands 2, 3 & 4 are the color bands. Combined, they create the true color of the image. Band 8 is used for adding details to the bump map. It is only used later on in blender to add bump detail. No coloring is applied to this map. The height map data (in blender the Displacement data) comes from the DEM image. No coloring is applied to this map either. When you are adding the colors to the map, are your images stacked the same way that mine are? In the tutorial, Blue is on top, then under that is Green, then Red. Band 8 and the DEM are below the color maps. The stack order is important. Make sure that the blending mode for the red layer (Band 4) is "normal". The blending modes for Blue & Green must be "screen" kzbin.info/www/bejne/Y6bFdaSOj9mXgKc If the blending modes are not set to "screen", you will not be able to see through them to the colors underneath.

[@pinyang8782]

@Mark_Alloway thanks! I have another issue is that I do get the rgb but not the screen. When I click screen, all my map disappears

[@pinyang8782]

@@Mark_Alloway As i realised my satilite data seems to have larger tile compared to the video

[@pinyang8782]

do you have anyway to reduce the tile size for landsat data?

[@arunseth4307]

followed the instructions carefully but when i do the export as img thing and select the crop layer in the menu it says the img is only 1px by 1px in resolution any idea what might be causing this to occur?

[@Mark_Alloway]

I haven't experienced that, but it sounds like it might be a scale or resolution issue. What values are you using in the Set Map As Image dialog box? One thing I have noticed that seems to mess things up is if you zoom in/out or move your maps while you are in the process of exporting the images. Did you move your maps at all?

[@seansersmylie]

@@Mark_Alloway Same issue, not sure how to fix.

[@Mark_Alloway]

@@seansersmylie I really wish I could help you, but I have not been able to recreate this error. If you do figure it out, please post a solution here.

[@Lad11971]

If you still need help I fixed it by closing qgis after making the crop box then just re openning youll just have to re raster the elevation data when you load back in but then when I selected the crop shape it didnt say 1px anymore

[@Mark_Alloway]

@@Lad11971 Thank you for taking the time to share a solution. I'm sure it will help others!

[@CatherineScott1]

It's 5:00 am and I have been trying to figure out why the "Shape Digitizing" icons are grayed out. I followed the steps exactly too many times to count now I have to put my computer to sleep first instead of shutting it down because if I do I will lose the temporary map (which is a lot bigger than yours) please help.😪😔😴

[@Mark_Alloway]

I'm really sorry to hear that. I know exactly how frustrating it isto precisely follow a tutorial and not have things work. I'm sure you've carefully repeated everything in my tutorial, so I'm guessing it's something not covered in my examples. (maybe double check the toolbar settings I show in the beginning of the video - they do affect icon availability) Have you searched Reddit or some other QGIS forum? There are number of threads where people have had similar problems.

[@tokeiitoo]

@@Mark_Alloway I am facing the same issue, and I'm not sure how to solve it

[@Mark_Alloway]

@@tokeiitoo Is the problem you are encountering roughly at this point in the tutorial? kzbin.info/www/bejne/Y6bFdaSOj9mXgKc and are you talking about the 5 icons on the far left of the bottom toolbar row?

[@MechanicalWhispers]

@@Mark_Alloway Yep! They were greyed out for me too. I solved it by clicking the "Add Polygon Feature" icon (or Ctrl+.)

[@Mark_Alloway]

@@MechanicalWhispers Clicking on the "Toggle Editing" pencil icon also turns them on. Thanks for helping.

[@FrancescoSpace]

This is awesome, thanks! One question, do you know what this data can be used for? Is there a content usage guideline somewhere?

[@Mark_Alloway]

My understanding is that the NASA/USGS data is public domain. I'm willing to bet the EU satellites are similar, but I can't promise that. I just tried to search the USGS website for usage terms, but the site is currently down for maintenance.

[@FrancescoSpace]

@@Mark_Alloway thanks for the swift reply! Hmm, could you let me know if you find more info on that?

[@Mark_Alloway]

@@FrancescoSpace www.usgs.gov/information-policies-and-instructions/copyrights-and-credits

[@FrancescoSpace]

@@Mark_Alloway I have tried the Landsat data but is really low res for closeups… 30 meters spatial size. I am trying to do Innsbruck and its airport so I would probably need 5 meters or less. Do you have any tips? I’ve seen the High Res Orthoimagery section but that’s only for the US.

[@Mark_Alloway]

@@FrancescoSpace Have you tried: earth.esa.int/eogateway/catalog/pleiades-esa-archive? The Pléiades satellite seems to have pretty high resolution data for Europe. I don't have an account on their website, so I couldn't dive deep into what they offer, but if you live in one of their member states, you should be able to access the data.

[@WoofDaddyBigPlums]

Excellent tutorial. No chance Of getting lost even for a second. I wish all tutorials were like this. Kudos

[@Mark_Alloway]

Thanks. I appreciate the comment