chelm
commented
10 years ago @YmerejRedienhcs I found this: http://stackoverflow.com/questions/10688729/checksums-on-zip-files
And then I ran this test: https://www.evernote.com/shard/s241/sh/e77e8836-78ea-4172-a503-51784e37256c/3c0e64ad7682741f8cf3fcceef3e1e56
Basically you'll need to unzip the contents of the file and run md5 sums on those, not the zip.
download of zipped shapefile was observed to be different on some different downloads, but should have been the same each time
The sizes of the valid zip files that I have downloaded since 11:30 pm August 13 are all the same (as shown below).
@ajturner told me you use the OGR library to generate the shapefiles. Could there be a way to cause it to produce the same zipped shapefile for the same input data? Or is it possible that maybe koop is simply not always providing the input in the same order to OGR?
This shows that the zip files are not always the same (though sometimes they are):
This shows that the recently downloaded zip files are all the same size (they weren't before):