I'm on QGIS (v. 3.6) trying to create a map of Florida's hydrography using the NHD "Water Areas" shapefile. Methodology is to fix any invalid geometries in the NHD data, dissolve the layer, and then execute the difference between water areas and the whole state of Florida. There quite a lot of these areas and it's obviously taking a significantly long time for the dissolve function to complete (I left it running for ~5 hours and the algorithm was still processing). This is running on a Thinkpad X1 Yoga. Is there a faster way to complete this project or is QGIS the wrong software for what I'm doing?
Ultimately, I ended up clipping the NHD layer (input) from a few Florida counties (overlay) that I needed, and then using the difference tool for what I wanted. I initially assumed using the whole NHD state layer would more efficient for what I wanted, but the time it took to fix geometries, dissolve the layer, and find the difference between the two layers would have taken way too long or crashed the program.
I tried the vector to raster method, but the level of detail I wanted still took a significant amount of time. I also selected and extracted polygons with areas over 1 sqkm.