[GIS] Adding many raster tiles to geopackage

geopackageqgisraster

I have many raster tiles (in tif format, SR WGS84) and, since all together are very heavy, I want to unify them in a geopackage.

I've tried to do that in QGIS, performing the following steps:

converting all the raster in PNG format,
creating a geopackage from the Browser panel (Create Database > No geometry)
simply dragging them into the geopackage created —> Import succesful

but: the original rasters have a single band, while once added to the geopackage they have 4 bands.

Is there a way to create a Geopackage that contains all my raster tiles (about 850 tiles) maintaining only the 1 original band?

Best Answer

Create with your 850 raster tiles a VRT ("Raster" -> "Other" -> "Build Virtual Raster"). Remove the tick from the checkbox "Place each input file into a seperate band". You can leave the other options as they are. Drag & Drop the VRT within QGIS into the Geopackage you prepared - Done

(or rightclick on the VRT, "export as" -> Geopackage )

Related Solutions

[GIS] R: Display single band raster in true color

I'm a little late to the party, but figured I could contribute a more complete answer to the question than the bits left in comments here.

raster::raster() only reads a single band when handed a multi-band raster, though it does let you choose which one via the band argument. As you wound up figuring out, for loading a single file as a multi-band raster, you want to use the raster::brick() function (or, if your bands are stored as separate files, raster::stack()). You're then able to plot the multi-band image via raster::plotRGB().

As for your second question, of why there are three bands to begin with: the PNG format your image is in represents each pixel in the grid with 3 (or 4) numbers: the amount of red in the pixel, the amount of green, and the amount of blue (with the 4th band being opacity). Each of those values are stored in the image as their own separate band, which is why you need to pull out raster::brick() instead of simply raster::raster() -- your original example was visualizing only the red band of the image, without paying attention to the other two values that make up the color for each pixel.

QGIS – How to Import Multiple Raster Files into One GeoPackage

Use the option: 'OPTIONS':'APPEND_SUBDATASET=YES|RASTER_TABLE=raster123', change the raster_table name with each iteration:

import os

newgpkg = '/home/bera/Desktop/all_rasters.gpkg' #Will be created if it doesnt exist
rasterfolder = r'/home/bera/Desktop/GIS/Data/testdata/' #All tif rasters in this folder and all subfolders will be converted

for root, folder, files in os.walk(rasterfolder):
    for file in files:
        if file.endswith('.tif'): #For each tif file in rasterfolder
            print('Processing {0}'.format(file))
            fullname = os.path.join(root, file)
            newname = file.replace('.tif', '_trans') #Adjust this line to change how the output rasters are named
            processing.run("gdal:translate", {'INPUT':fullname,'TARGET_CRS':None,'NODATA':None,
            'COPY_SUBDATASETS':False,'OPTIONS':'APPEND_SUBDATASET=YES|RASTER_TABLE={0}'.format(newname),
            'EXTRA':'','DATA_TYPE':0,'OUTPUT':newgpkg})

Best Answer

Related Solutions

[GIS] R: Display single band raster in true color

QGIS – How to Import Multiple Raster Files into One GeoPackage

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