[Resolved] requesting checker for GC5QM86

Please can a checker be created for GC5QM86 Explorer 302 Challenge (Northallerton & Thirsk)

This is the same principle as the existing checker for GC5JFNQ Explorer 300 Challenge, but has a different map area and requires a minimum of 127 squares to be found (rather than the 110 squares.

I have qualified - at the time of publication of the cache I had 148 squares.

Many thanks

Sowerby

It will take some time for us to do since we will need to convert all the UTM coordinates to latitude and longitude and then build the polygons.

I will look into it later tonight if vogelbird doesn’t beat me to it.

Thank you. There are a number of other Explorer Challenges that alreday have challenge checkers if that helps, including
https://coord.info/GC4KFEW
https://coord.info/GC3CW70
https://coord.info/GC3HEC6

Okay, this is more difficult than I thought because datum conversions. This will take some time. I want to write a generic script that could apply to any of this OSGB map grid challenges.

I started a script based on the GSAK macro (some of these explorer challenges are old requests that I was trying to clear out). It works now minus the OSGB datum conversion... Apparently GSAK had that conversion internal. I had some JS code that does.it, but when I converted it to Lua, it didn't work anymore... And I haven't come back to figure out why yet.

Ah, hello! I hadn’t looked at the GSAK script and instead started working on translating the OS grid -> latlng part of https://www.movable-type.co.uk/scripts/latlong-os-gridref.html but it has been somewhat slow. Maybe its datum conversion code helps?

Well... the final latitude seems to be wrong but the longitude is correct. Not sure where my mistake is; I assume it's in the final cartesian-to-lat-lng code (since the longitude is correct).

https://gist.github.com/hughcoleman/cbecc52778ed6491a95a00b905f78510

Ah, found the bug. Turns out 1e6 is 1000000, not 100000.

Alright, @Sowerby, can you confirm to me if these squares look good?

https://project-gc.com/Challenges//79251

Run the checker and then scroll down, look for the map.

(I'll update the grid labels to use the XX 00000 00000 format once you confirm -- no point doing that if the polygons are wrong.)



Edited 5 time(s). Last edit at 07/10/2023 01:41AM by Hügh. (view changes)

@Hügh

The squares are correct

Many thanks

Wonderful. You can link to https://project-gc.com/Challenges/GC5QM86/79251 on your cache page then.

@Hügh

Many thanks - you are a star

If that works, you can probably easily apply it to the ones I was looking at:
https://project-gc.com/forum/read?8,54860

Oh, I think so, yes! There are a couple other adjustments I want to make so I will do those first. It will be nice to get that old thread marked as completed.