Merge Raster Layers in QGIS (Create a Raster Mosaic)

[@vidarvaggen]

Not all heroes wear capes! Well you might wear a cape for all I know, but seriously: THANK YOU SO MUCH! I was starting to panic. I have one week to make a 3D map for a TV show. Have done it before, but not at this scale. I didnt have three tiles, but 658 tiles in a horrible mosaic of different gray scales. Now I have one big beatiful and smooth terrain. Thank you again sir!!

[@geospatialschool]

Glad I could help!

[@nounsiart]

Hello, thanks for the video. I have a question please, why I don't have python3 -m in the GDAL/OGR console call, thank you

[@Ayomide_Igbaroola]

Thank you. This video really saved me from so much headache.

[@geospatialschool]

Glad it helped!

[@ola43321]

Very helpful, glad I found it, thanks!

[@geospatialschool]

Glad it was helpful!

[@carlosabellanosa]

Thanks. I resolved in another way due to I got an error during process. Every tile has a min and max elevation according to white (max) and black (min); so every tile has more or less its own grayscale. I downloaded 18 tiles with HUGE tone differences between each other: a mess. What I did is to find the lower altitude and rewrite this min to all tiles (in the video is 1389.49); same with max (in the video 3301.7). Dobleclicking the layer will open a info chart to change these data. Tara! The result its a beautifull smooth heightmap.

[@carlaocano6660]

Thanks for your video! I am working with images from Sentinel 2. Do you know the procedure if the images have some black areas and if they have some overlapping areas, how can I choose the image I want in the final product? From already thank you very much

[@MrEliteMossy]

when i try to merge 2 rasters a black screen appear in there place after the proccess any help?

[@laplaceha6700]

Excuseme, is it possible to change the merging order? I'm merging different bands of image to a single image with multiple bands，but it seems QGIS has its own default merge order.

[@stratospheros]

Thanks for useful method and your deep knowledges in qgis.

[@geospatialschool]

It's my pleasure

[@mbifteki1]

hi! I am trying to merge virtual rasters with the same procedure and I get an error: RuntimeError: Writing through VRTSourcedRasterBand is not supported. Is there anything specific about merging virtual rasters? Thank you for your video!

[@rafiaja6039]

Thank you so much for the tutorial :) and i want to ask you about the code for GDAL/OGR console call for mine is different from you so how to change the program just like you

[@itrstt66]

it gave an error saying it was saving in too many bands what is a band?

[@dak4482]

hi, I have a county size group pf 1000 lidars (.laz's)that I had to break up into 3 projects because QGIS kept choking on any group larger than around 500 layers. How would I go about merging all 3 of those groups of layers into one project/tiff file. Thx in advance for any help. ....Dan

[@geospatialschool]

With that many files I wouldn't use QGIS. You're getting to a point where you probably want to store and analyze those data on the cloud

[@dak4482]

ok thx @@geospatialschool

[@gavinjones7187]

Can you merge aerial images with the raster to give it colour then export as a colour point cloud

[@icarosanchesdeandrade3667]

What're your machine configuration? I'm trying to merge some files in a i5 with 8gb ram and a SSD The files size are 600 mb And does it works with overlayed layers?

[@am1BOTEA]

Thank you :)

[@wagnersarto7994]

very cool!! How could I merge a raster of the whole country? I feel that it is not feasible, because the memory goes to infinity. But is there a way around it?

[@geospatialschool]

Depends on the resolution of your rasters and the amount of memory your machine has. It could be done, it might take forever and require writing custom code. Or a machine with enough memory

[@jonghojeong3857]

Thank you for this

[@geospatialschool]

You're welcome

[@lassinesanankoua4743]

Thank you very much

[@geospatialschool]

You are welcome

[@ViCtOrBization]

So usefull. Just a question... when i do the same with two different dem, the merged output has a maximum value lower than the maximum in one of the original ones. Some idea about why is it doing this? If i check the higher areas with the "identify features" of the merged file I find pixels with higher values than the maximum... it's just weird

[@geospatialschool]

It's probably just that the statistics weren't recalculated or were only calculated on a sample of values. There's a QGIS tool to calculate the statistics

[@ViCtOrBization]

@@geospatialschool Your're right, thanks a lot

[@danielwarren4541]

@@geospatialschool can you direct me to the tool you mention - I am having the same problem

[@pitruchhaya]

Hi. Can you please let me know why do the min and the max elevations of the merged raster dont tie in with the other individual rasters? Second, can you please point me to your video wherein you can stamp rasters with some intersection between them and asks user the sequence to stamp?

[@geospatialschool]

You may just need to recalculate the statistics. Sometimes the raster statistics are computed from a sample instead of all values.

[@pitruchhaya]

@@geospatialschool Thanks for your response. I will check this. Can you please answer my second question too?

[@gaborfekets6899]

@@geospatialschool Hi, thanks for your video. I have the same problem. After clip, or merge the new MIN/MAX values are different. The new MAX value is higher, then the old image file. Recalculated, but still the same problem. I'm new at this QGIS world, can you please help how to step forward? Thanks.

[@geospatialschool]

Are the statistics on the original rasters correct? And how different are the new values? Resampling does happen when doing the merge so the values may be slightly different.

[@khinmyatchae4878]

Thanks for sharing

[@geospatialschool]

Thanks for watching!

[@rec11fdc]

Thank you for this! I have a question though, I've tried it with a large amount of files (70Gb of information) and it tells me there isn't enough disk space to store the resulting file. The disk however has over 400Gb of free space. Does the merged file actually take that much more space than the mosaic files?

[@geospatialschool]

It could be that the error is not for writing the result to disk, but loading it into memory. Depending on how it works behind the scenes you could be limited by RAM

[@hohvideos3238]

it also may be a compression issue. If the original files are compressed and the resulting file has no compression, it can be a lot larger than 70 gb.

[@36zero97]

Qgis 3.18 please...

[@geospatialschool]

It's the same.

[@Cuudiee]

why are u so confused with whatever ur trying to show in thi video....