This is my third post on the new beta release of the ISTI temperature database. In the first post, a Google Maps display, I noticed a number of stations which appeared to be duplicates. So I thought I'd check more comprehensively.
I first ordered the inventory alphabetically by name. A complication here is that 430 have no name. Some still showed up as duplicates.
The next step was to collect pairs of adjacent stations whose data began in the same or adjacent year. Then I did a rough distance check and retained pairs for which the sum of lat and longitude differences (absolute value) was less than 1°. That's within about 70 km at most near the equator, requiring greater closeness near the poles. In fact most pairs at this stage have near identical coordinates.
That left 1077 pairs. I've made a list as a zipped CSV file here.
There will be some missing. I suspect Vienna/Wien are duplicates, but are missed alphabetically. The two Trondheims I noticed are assigned coords too far apart. And of course, my test doesn't prove duplication - just flags for checking.