Good morning, I have a problem with the creation of a mosaic for 2 OLCI products, and I selected the 3 bands as the variables I need, but the output product has a very strange size, 7153 x478 , and a very bad quality as an RGB image. What could be the problem? by the way the processing of the mosaicing is even too fast and the outproduct is about 80 MB.
Thanks in advance
The mosaic is not preserving the resolution automatically. Maybe you need to adjust the pixel-size?
yes, probably it is the only parameter that can be modified to improve the output quality. I did not think about this because I thought it was working similar to the SLSTR stitching…
Do you know which could a good value to set?
I would like to get the same resolution, so in the end an image larger than a single OLCI one 
Try with a pixel size of 0,00257 degree. This is roughly 300m.
I’ve computed it like this.
pixelSize = (360 / 42000000) * 300
360° divided by the circumference of the earth in meter times 300m
Oh thanks!! I was going to do the same kind of computation but I thought there could have been some standard value you have been given as a developer of S3tbx 
Good morning! Actually with this setting the mosaic has the right size, so it works. Is it possible to obtain a mosaic without a reprojection mode?it seems from the settings that it is not possible to unable the reprojection. Thanks Marco!
Good that it works.
The reprojection is needed. A stitching is not implemented.