Fix "Tile index out of bounds" error for very north tiles

[danscales]

Fix "Tile index out of bounds" error for very north tiles for dynamic tile access

We are hitting the edges of the whole-world bounding box for very north tiles, and need to add some rounding to deal with slight imprecision in the floating point computations.

[jterry64]

This looks right, but maybe you can quickly confirm that round(right, 0) > round(max_right, 0) gives the right answer for the numbers we were looking at in your python console?

[danscales]

This looks right, but maybe you can quickly confirm that round(right, 0) > round(max_right, 0) gives the right answer for the numbers we were looking at in your python console?

Yes, here is the output, where we get True without rounding (which leads to the error) and False after rounding (because right and max_right become equal):

Python 3.10.12 (main, Sep 11 2024, 15:47:36) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import mercantile
>>> mercantile.xy_bounds(0, 0, 0)
Bbox(left=-20037508.342789244, bottom=-20037508.342789244, right=20037508.342789244, top=20037508.342789244)
>>> mercantile.xy_bounds(7, 2, 3)
Bbox(left=15028131.257091936, bottom=5009377.085697311, right=20037508.342789248, top=10018754.171394622)
>>> 20037508.342789248 > 20037508.342789244
True
>>> round(20037508.342789248, 0) > round(20037508.342789244, 0)
False
>>>