How to merge multiple GeoTIFF tiles into one file (QGIS)
This guide explains how to merge several GeoTIFF tiles into a single GeoTIFF using QGIS, and how to prepare the merged file for upload to Novorender (orthophoto draped on terrain).
When you need this
You should merge GeoTIFFs when your orthophoto or terrain model is delivered as multiple tiles, for example:
Orthophoto_tile_01.tifOrthophoto_tile_02.tifTerrain_tile_01.tifTerrain_tile_02.tif
Novorender works best when the orthophoto and terrain are uploaded as one file each.
Step-by-step: Merge GeoTIFF tiles in QGIS
1) Add your GeoTIFF tiles to QGIS
Open QGIS
In the QGIS Browser Panel, locate the folder containing your GeoTIFF tiles
Select the GeoTIFF files you want to merge
Right-click and choose Add Layer(s) to Project
This will load the tiles into the main map window.
2) Open the Merge tool
Go to:
Raster > Miscellaneous > Merge
3) Select input files
In the Merge dialogue window:
Under Input files, click Browse
Navigate to the directory containing your GeoTIFF tiles
Select all tiles:
Windows: hold Ctrl and click files
macOS: hold Shift and click files
4) Define the output file
Under Output file, choose a filename and make sure the format is:
.tif(GeoTIFF)
Example:
Orthophoto_merged.tifTerrain_projectX_DSM_merged.tif
5) Enable compression (recommended)
In the Merge window:
Select the Creation Options checkbox
In the Profile dropdown, choose a compression level
Recommended: lossless compression
Not recommended: JPEG compression
JPEG compression is not recommended for GeoTIFF merge export, as it may reduce quality and introduce artifacts.
Note on file size:
When merging two GeoTIFFs of 5.24 GB and 8.55 GB without any compression, the exported merged file became 24 GB. Compression can significantly reduce disk usage.
6) Run the merge
Click OK to start merging.
Merging may take a long time depending on dataset size and computer performance. Be patient and allow the process to complete.
Example reference time:
A merge took approximately 2.5 hours on a late 2013 iMac.
After merging: Prepare files for Novorender upload
To drape an orthophoto on terrain in Novorender, you need two GeoTIFF files:
1) Orthophoto (image)
Orthophoto.tiforOrthophoto.tiff
2) Terrain model (DSM or DTM)
DSM.tif / DSM.tifforDTM.tif / DTM.tiff
Naming requirement for terrain model files
The terrain model file name must include DSM.
Example:
Terrain_projectX_DSM.tif
If a .TFW file exists, match the same naming:
Terrain_projectX_DSM.tfw
Folder structure and zipping requirements
Before uploading to Novorender:
Place all required files in the same folder
Zip the folder into one
.zip
Example folder content:
Orthophoto_merged.tifTerrain_projectX_DSM_merged.tif
If .TFW files exist, include them too:
Orthophoto_merged.tfwTerrain_projectX_DSM_merged.tfw
Notes about .TFW files
With a correctly created GeoTIFF, you typically only need the .tif file.
However, if a .tfw file was automatically generated together with the .tif, include it in the same folder before zipping.
The .TFW file contains spatial referencing information.
