Define Projection of multiple rasters at once

[Nick_Creedon]

I create annual/biannual basemaps for our city. We have a subscription to an Imagery company that provides projected, georeferenced imagery for the taking. In order for us to have a detailed basemap, I must zoom in and export sections at a time. I export roughly 150 images, then I unzip them into a folder and add them all into my ArcGIS Pro project. The end product is that these basemaps are hosted in ArcGIS Online. I will get a warning message that these images have to be projected prior to sharing to ArcGIS Online, so I have to one by one use the Define Projection tool to set the proper projection. Even though I export them from the website "projected" and they are already spatially accurate, they need to be projected again in ArcGIS Pro.

I have created a work around, but it would be easier if you can select multiple rasters for Define Projection.

Here is my current workaround:

[MErikReedAugusta]

Is the contracted company not able to directly deliver the projected files?  It sounds to me like the downloaded files actually aren't retaining their projection, if you're having to define it.

More to the problem at hand, though, have you tried right-clicking "Define Projection" and creating a batch tool?  That should allow you to provide multiple source images, provided they all have the same projection.  In batch mode, the tool then runs each iteration in succession, so it'll likely take a while to loop through multiple input images.

[Nick_Creedon]

They will deliver us a full basemap of our area of interest for more $$

The files appear to still be projected, because if you select another projection on their website and export it, an bring it into ArcGIS Pro it displays elsewhere. The projection setting doesn't adhere to the raster coming into the project for some reason.

This sounds like an option, this isn't a practice I am familiar with. My workaround does work well but I will be happy to try this out.