# Raytheon corrected RPC file directory?

[Calsia]

In input.ini, there is a parameter named rpc_dir. how can i get this file？
thans for any response.

[Calsia]

[mleotta]

rpc_dir should be optional. It's only used when running Danesfield with a proprietary software alternative to the VisSat pipeline for computing point clouds from satellite images. That other software also estimates corrected RPC projection models that replace the models found in the image headers. VisSat currently does not. If rpc_dir is not used we stick with the original RPC parameters that come with the images.

[Calsia]

That is to say, using vissat, I can directly set it to 'None', right?

[Calsia]

rpc_dir should be optional. It's only used when running Danesfield with a proprietary software alternative to the VisSat pipeline for computing point clouds from satellite images. That other software also estimates corrected RPC projection models that replace the models found in the image headers. VisSat currently does not. If rpc_dir is not used we stick with the original RPC parameters that come with the images.

I was just curious before, why do you need an extra file when you already have it in the image headers

[mleotta]

I believe just not including (e.g. commenting out) that rpc_dir is what you want. Setting it to None may work, but I haven't checked if that string "None" would be parse into a Python None or not.

This is needed because some tools can optimize the RPC values found in the image headers to get better results. We treat the input images as read-only so we don't want to write these value back to the image headers. Instead we write this metadata into optional sidecar files that taken precedence over the header data, if provided.

[Calsia]

Thanks for all the help on this and your responsiveness.