Different distances between GPS coordinates and converted values in meter. about proj4js

[ahocevar]

First of all, there is no need to convert from GOOGLE to WGS84, because Google Maps reports the coordinates in WGS84. And regarding the distance calculation, you'll want to use a different tool than proj4, e.g. turf/distance.

[Nic-77]

Hi @ahocevar !
Thanks for your response!

My use case is the following:
Currently, i have a tool (BabylonJS based) where i insert a map section from Google. On this section i want to place a marker, which is possible to move on the map section.
After/with moving the marker i want to calculate the new position.
So, therefore i converted the coordinate from google into meter, add the moving distance (also in meter) and converted this back to WGS84.
But therewith i got wrong positions.

[ahocevar]

Like I said, you're doing the wrong thing. GOOGLE is a pseudo projection only used internally. Google Maps reports latitude/longitude in WGS84. And geographic coordinates is not something you can measure distances with. You can either transform coordinates into a local projection with meters as distance units (with proj4), or you can use turf/distance or a similar tool to measure distances on a sphere, based on the original geographic coordinates.

[Nic-77]

Ok, thanks for explanation!