Live Map not showing caches (too many on zoom=17)

Question

During my visit to Prague, I noticed, that Live map fails to show caches with warning

Warning! Too many geocaches in the visible area, not fetching them. Please zoom in to resolve.

In log:

GetGeocaches() 14.382508993148802,50.09862889433957,14.402410984039308,50.10595788189813
Calculating tiles
Too many geocaches in visible area, informing user

Example link:

http://project-gc.com/Maps/LiveMap#c=50.10229,14.39248;z=17

Moving the map little bit to the north shows around 20 caches, but the log reports

GetGeocaches() 14.38008427619934,50.10002596156413,14.399986267089844,50.10735473538969
[...]
GetGeocachesWithinBoundingBox() 50.2,14.4: success
[...]
Number of geocaches in memory: 36
GetGeocachesWithinBoundingBox() 50.1,14.3: success
[...]
Number of geocaches in memory: 271
GetGeocachesWithinBoundingBox() 50.1,14.4: success
[...]
Number of geocaches in memory: 633
GetGeocachesWithinBoundingBox() 50.2,14.3: success
Number of geocaches in memory: 713

Which looks like the map is picking up a big tiles from surrounding area (city center) and it is exceeding some internal limit. Therefore the map is basically unusable (I agree that Prague is probably the place with highest density of caches all around).

Would it be possible to check what can go wrong in these places, that the map is not pulling too many geocaches and that the map is usable in such places?

Comments

I notice this in the UK, and this isn't (I think) as dense as Prague, except maybe in Central London!

edit: not an aswer but a comment

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This topic has been bookmarked for future investigation. It seems like Target has some very good points in his answer.

Answer 1

The is a fix for that on the page. Use the cogwheel button below the filters to open setting. increase "Max visible geocaches" to a higher value. It is 2500 by default and it is less the the number in the bounding box that is used.
if I set it to 5000 the link will load.

But is still a bug. The code should always load the max zoom level regardless of limitation or give a correct error.
The page loaded 9 tiles from zoom level 14-17 on that coordinate. the tiles is 0.1 degrees So if the is more then  Max visible geocaches caches in the .3 degrees square around the cache the page will never load
It should be possible to reduce the min number of tiles to 4. You need that if you look

I would suggest that the minimum number of loaded tiles is reduced to 4

The error message is misleading since zooming don't reused the area looked at "if(data.totalGeocaches <= PGC_LiveMap.maxVisible) {" is the only test.

It should check if the min number of tiles is used. If that is the case the error message should not be zoom but to increase Max visible geocaches in setting or move the map to another place

It might be an ide to always load min number of tiles.