Orthomosaic export is normally used for generation of high resolution imagery based on the source photos and reconstructed model. The most common application is aerial photographic survey data processing, but it may be also useful when a detailed view of the object is required. Metashape enables to perform orthomosaic seamline editing for better visual results (see Orthomosaic seamline editing tutorials).

If the lighting conditions have been changing significantly during capturing scenario, it is recommended to use 'Calibrate colors' option from the Tools menu before Build orthomosaic procedure. The option can help to even brightness and white balance of the images over the data set. Please note that for large data sets Calibrate colors procedure can turn out to be quite time consuming.


Color calibration

1. Select Calibrate colors... command from the Tools menu.


2. Select the desired colors calibration parameters in the Calibrate colors dialog box. Click OK button when done.

Source data:

Defines what data should be taken as the basis for overlapping areas estimation. It is preferable to select the source data type according to the surface which you plan to project the orthomosaic on. 

  • Sparse cloud - the quickest yet the roughest estimation available.
  • Model - gives more precise results, but only on condition that the surface is detailed enough.
  • DEM - is a reasonable alternative to the Model value for large data sets when it is not feasible to reconstruct solid polygonal model (mesh).

Calibrate white balance 

Additional option to be switched on if white balance should be evened as well.


3. The progress dialog box will appear displaying the current processing status. To cancel processing click Cancel button. 



To build Orthomosaic 

Note: Build Orthomosaic procedure can be performed only for projects saved in .PSX format for chunks with the existing mesh or DEM.


1. Select the Build Orthomosaic... command from the Workflow menu.

2. In the Build Orthomosaic dialog box set Coordinate system for the Orthomosaic referencing or select projection type. 

3. Select type of surface data for orthorectified imagery to be projected onto. 


4. Click OK button when done. 


5. The progress dialog box will appear displaying the current processing status. To cancel processing click Cancel button. 


Note: More than one instance of Orthomosaic can be stored in one chunk. In case you want to save current Orthomosaic instance and build new one in current chunk, right-click on Orthomosaic and uncheck "Set as default" option. In case you want to save current Orthomosaic instance and edit its copy, right-click on Orthomosaic and choose "Duplicate" option.


Orthomosaic export


To export Orthomosaic:

1. Select Export Orthomosaic... command from the File menu. 


2. In the Export Orthomosaic dialog box specify coordinate system for the Orthomosaic to be saved in.

3. Check Write KML file and / or Write World file options to create files needed to georeference the orthomosaic in the Google Earth and / or a GIS . 


4. Click Export... button to start export.


5.
Browse the destination folder, choose the file type, and print in the file name. Click Save button.


6. The progress dialog box will appear displaying the current processing status. To cancel processing click Cancel button. 


Note: Write KML file option is available only if the selected export coordinate system is WGS84 due to the fact that Google Earth supports only this coordinate system.

World file specifies coordinates of the four corner vertices of the exporting orthomosaic. This information is already included in GeoTIFF file, however, you could duplicate it for some reason. If you need to export orthomosaic in JPEG, PNG or BMP file formats and would like to have georeferencing data this informations could be useful. 

The following formats are supported for orthomosaic export:

  • GeoTIFF
  • JPEG 2000
  • JPEG
  • PNG
  • BMP
  • Multiresolution Google Earth KML mosaic
  • Google Map Tiles MBTiles
  • World Wind Tiles
  • Tile Map Service Tiles