cachemap should display caches at modified cords, not at original

[kojoty]

HI @wrygiel,

We have issue opencaching/opencaching-pl#913.

Do you think it could be easy implemented at OKAPI side?

[wrygiel]

Do you think it could be easy implemented at OKAPI side?

OKAPI is using a separate index of cache locations to make the tile generation faster. This index is global (one index per all users). Displaying caches at modified coords would either require N indexes instead of 1 (where N is the number of users), or dropping the index altogether. Only the second of these options is feasible (dropping the index), but I'm not sure how performance would suffer.

[wrygiel]

I'm not sure how performance would suffer

Just to clarify, I'm sure that it would suffer, but I cannot tell how much. My tentative guess is that it would make map generation at least 10 times slower, especially for lower zoom levels.

I believe that we would not only the resigning from this particular custom index of mine - we also wouldn't be able to use the default index (the one in caches table). We would need to query the services/caches/search/bbox method with location_source=alt_wpt:user-coords for every tile request. And, as far as I know, this location_source doesn't use any index whatsoever.

[kojoty]

@wrygiel, thanks for answer
I think we can close this issue - it seems there is no good way to implement it.

[wrygiel]

I think we can close this issue - it seems there is no good way to implement it.

I think I can see a way of solving this, but it certainly isn't easy :) and I won't have time to implement this any time soon... We need to use two indexes - the existing one, plus a set of new ones (one small user-coords index per user). If the second index is cached in APC (e.g. a couple of recently used indexes), this would work almost as fast as the current solution.

[andrixnet]

Could this be related to the ability to show/hide caches other then current on cachepage popup map and the ability to show waypoints of a cache on the map ? (see here opencaching/opencaching-pl#90 )

[andrixnet]

Also, IMO such a feature should display both : the original cache coordinates (with proper icon), given that those coords may have significance for some field puzzle caches and not only.
And the user coords with a different icon, also different from owner defined waypoints

[following5]

See also #496. I guess we don't want to publish the modified coordinates ...?

[following5]

Could this be related to the ability to show/hide caches other then current on cachepage popup map and the ability to show waypoints of a cache on the map ? (see here opencaching/opencaching-pl#90 )

I don't think it is related. Generating minimap for just one cache would be a very different thing than the current OKAPI map.

[following5]

This issue is on hold, because there are different requests:

• Show modified coords instead of original coords (kojoty), or
• show modified coords separately, with special icon (andrixnet).

OCPL developers/users must decide what the map should display.

[kojoty]

My thoughts:

• modified coords are useful for quizes, which needs to be resolved offline, sometimes long time before the trip to the place, where cache is hidden in terrain.
• then user usually doesn't need to see cache on original coords - useful is only new "real" position
• I think, that probably it would be well if cache on modified coords should have some graphical identification (different icon - some addition to icon) - there is no reason to show original coords on map.

@andrixnet what do you think?