Legacy windows software usually. I had to use something like this for soil sampling when I worked for farms.

All the locations are programmed in an old obscure format that only works with one program, and there’s hundreds of fields with dozens of points each. It was just easier to stick with windows that port everything. Plus they’re more rugged than an iPad in an otter box.

Also, in my case the windows PC had a higher precision gps (mini pcie card) that is not available on consumer devices due to extra licensing, and external base stations.

Laptop was probably an option but would have been even heavier for the same level of ruggedness. These days though most laptops don’t have any internal expansion ports aside from m.2, so it probably wouldn’t work for the reasons we needed one.