Re: Improved checker: country borders

We have a challenge of the DeLorme type, called 'Belgium Topo50 Challenge' (https://coord.info/GC6G2MT).
The challenge is to have found at least one cache for each of the 57 maps, within the borders of Belgium.

The script GenericPolyChecker seemed to work really well, but recently a geocacher met the challenge but didn't get a green light from the checker because of a (traditional) cache within the borders of Belgium for which the cache owner entered Luxembourg as the country on the listing page.

Would it be possible to modify the script in order to filter the found geocaches not by the country on the listing page, but by the Belgian country borders as used by Project-GC?

The polyset is already based on the bourders of Belgium as used in the OSM data (PGC data) and not on the listing.
Can you give the cacher,s name so we can have a look what you mean.

Thanks for your reply!

I believe someone already mentioned earlier that the script was based on those borders, but couldn't find that remark in my mailbox or on the forums anymore...

Anyway, the cacher is 'les bois de les forges', who has found 'op der Grenz' (https://www.geocaching.com/seek/log.aspx?LUID=ef6e3e43-1e08-4c86-9c10-9b8a8316a95a), but doesn't get credit for finding a Belgian cache on map sheet 61.

You are wright , the cache is in Belgium with a PGC address E421, 4790 Burg-Reuland, België

On the OSM map it is clearly inside the Belgium border.
I will further investigate what the problem is

I learn something everyday. A cache which is marked by the CO as a cache in Luxembourg will remain undetected in the polygon checker.
This is the comment from PGC-HQ
Project-GC never changes country of a geocache. If the country is wrong, it should be fixed by the cache owner, a reviewer or HQ.

I also found this example for the Belgian-Dutch border: https://coord.info/GLMT6PY0.
So I assume the filter does in fact use the country on the listing page, which leads again to my initial question...

Would it be possible to modify the script in order to filter the found geocaches not by the country on the listing page, but by the Belgian country borders as used by Project-GC?

What are my other options?
- Asking the cache owners to change the country on the listing page, which will require their cooperation.
- Changing the challenge to include non-Belgian caches on the map sheet, which I don't prefer.
- Changing the polygons used in the checker, which would require the use of multipolygons because of some exclaves (Baarle-Hertog) and enclaves (Baarle-Nassau + Vennbahn).

Edit: I assume it is possible to filter by country borders, as it is also possible to filter by county borders...



Edited 2 time(s). Last edit at 10/18/2017 08:15AM by Team Pixie. (view changes)

I look at your third option because the first two are already concluded

Changing the polyset:
This will be a major job
The border consists of 47638 coordinates with 36 polygons and an extra 11 polygons to extract from Netherlands and Germany because this are area's inside the Belgium polygons.
Also of the existing polyset the polysquares are simple squares, For a new polypoints set the corners of these squares have to be extracted from the old set and incorporated in the OSM boundaries.
A rough estimation to build the polyset is 20 to 25 hours which is, looking at the few caches which are affected, a bit out of proportions to do all this work.

I think just asking the CO's to change the country is a lot less work

A lot less work, but when the CO doesn't respond the country will stay the same.
(One week ago, I sent a message to the CO of the cache that triggered this request, I had no response yet...)


The option you looked at was the third alternative. My prefered choice would be the use of the country borders in a script. If PGC can check county polygons, doesn't that also mean it can check country polygons (with a new script)?

The creation of a new polygon set will be a major job, but I'm prepared to do that myself. I already made the previous one (which, for the record, doesn't contain squares but polygons with about 30 corners each). However, I would need an example of how to include the Belgian exclaves and exclude the Dutch and German enclaves in the json file.
I see two drawbacks for this approach: the first is that I don't know whether the script will still be adequate / able to run (because of the exclaves and enclaves, and the high number of corners), the second is that the polyset will have to be recreated whenever the border changes (e.g. the recent transfer of some land between the Netherlands and Belgium or a possible future transfer of the Vennbahn to Germany).

OK I contact you directly so we can exchange files directly. I will close this thread so it does not linger on