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Merge tiles: failed to create tile reader!

I have tried 3 times to process a 10 Ha survey captured with a Micasense Rededge. I have 64GB of RAM and an writing to a disc with almost 1 TB of free space.


Steps 1 & 2 process fine with only a general warning about images exceeding lat and long limits. I read that this is not normally an issue.

Step 3 however fails every time with a warning message and two error messages:


Ortho gain: cannot load precomputed gain data. It will be computed.


  1. Merge tiles: failed to create tile reader!

2. Merge orthomosaic tiles [Blue] failed!

I have used the standard Ag Multispectral template but manually added 10 GCPs after step 1 followed by reoptimise.

Can anyone suggest what the problem might be?

Hi Graeme,

Other customers have encountered this error when generating orthomosaics with images captured with a MicaSense RedEdge camera. In their case, it seems the captured images were 12 bits and Pix4D cannot generate orthomosaic for 10, 12 and 14 bits TIFF images. Click here for more information.

Could you check if it is the case for you as well?

Also, you have used the Ag multispectral processing template which is recommended with multispectral imagery. However, by default, the orthomosaic should not be generated in that template. Please ensure the box GeoTIFF in the processing options of the orthomosaic is not checked.

Note that we recommend generating reflectance maps with multispectral imagery, which preserves the original pixel values and allows analyzing them. On the contrary, it is not recommended to use the orthomosaics because they are color-balanced and do not keep the true pixel value.

Let us know how it goes.