2 questions: "confusion about EPSG:900913" and "performance of Equirectangular projection" about geo-three HOT 4 OPEN

since epsg:3857 cuts the map at +-85° latitude, im kinda confused about the projected coordinates, i guess that is why people had problems with extremely distorted poles. right now i use +-19949545.833216466 as boundary, but thats not really relating to 40030/2 (Earth's circumference/2). 19949545.833216466 derived from datumstospherical-boundaries with mapscale=Earth's circumference*10^x

from geo-three.

ok i get it now, the epsg guys refused to give it a valid epsg number:
[Unfortunately, however, EPSG were rather dismissive of the system used by Microsoft and Google (more details in a bit) and refused to assign it an official EPSG code. An EPSG statement (as reported by Morten Nielsen ) read:
------>“We have reviewed the coordinate reference system used by Microsoft, Google, etc. and believe that it is technically flawed. We will not devalue the EPSG dataset by including such inappropriate geodesy and cartography.”

from geo-three.

allrighty i finaly found the awnser to my question:
" I think the confusion comes from that they actually use two spatial reference systems at the same time:
Geographic Longitude/Latitude coordinatesystem based on the standard WGS84 datum.
Mercator projection using a datum based on WGS84, BUT modified to be spheric.
... If you want to create image overlays, or roll your own tile server on top of the map, you will need to project your images into a spheric mercator projection. The JavaScript APIs are not able to do this for you.
Here’s a bit of facts about the two projections:
The valid range of (1) is: [-180,-85.05112877980659] to [180, 85.05112877980659].
The valid range of (2) is: [-20037508.3427892, -20037508.3427892] to [20037508.3427892, 20037508.3427892]"
those are the boundary values i was looking for!!!!!!!!! i thought that only lats below |85°| are valid, while the tiles are actually streched over the fixed earth circumference, but this is only true for the non-spheric mercator projection(1)

from geo-three.

so is it possible to use Equirectangular projection for planes?

from geo-three.