I have what should be a simple problem: erase a large multipart polygon layer from a larger polygon (see below for example). However, I believe the Arc Erase tool is trying to erase each part of the multipart from the larger polygon. I'm currently pushing 24 hours processing with ample storage and 12gb ram...
I have tested the Erase vs. Dissolve --> Erase workflow on a smaller dataset, and Erase runs substantially faster with the single dissolved polygon (~2 minutes for Erase with multipart, ~1 second with single feature in test dataset). Unfortunately, Dissolve also takes around 2 minutes with the same dataset.
So, is there an alternative to Dissolve that will return the outer extent of my feature class? I can not simplify the boundary with a convex hull or minimum bounding extent, I just need the feature mask. I'm open to python options as well.
UPDATE: Unfortunately, none of the provided answers gave me any great improvement in processing. I ended up buffering the inner dataset by 1 cm (smallest integer value available in Arc Buffer tool, and difference between inner and outer layers is ~150m) and erasing with that single polygon dataset.