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uber / h3

Hexagonal hierarchical geospatial indexing system
https://h3geo.org
Apache License 2.0
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Can I use another coordinate system？ #543

Closed changechenhao closed 2 years ago

changechenhao commented 3 years ago

I know document said:The hexagonal grid system is created on the planar faces of a sphere-circumscribed icosahedron, and the grid cells are then projected to the surface of the sphere using an inverse face-centered polyhedral gnomonic projection. The coordinate reference system (CRS) is spherical coordinates with the WGS84/EPSG:4326 authalic radius. It is common to use WGS84 CRS data with the H3 library.

Can I use another coordinate system？for example：EPSG:3857，Will it have any other impact？

nrabinowitz commented 3 years ago

All input and output coordinates are expected to be in WGS84 latitude/longitude coordinates, based on a spherical model of the Earth. If you wanted to use another coordinate system, you'd need to transform input/output yourself - H3 doesn't provide any affordance for selecting another coordinate system within the library. Internally, H3 uses a spherical model and radian coordinates; the only parts of the library that consider an Earth-centric model (i.e. that use the Earth radius) are area and distance functions.

changechenhao commented 3 years ago

Thank you.