From IT Skills
Jump to: navigation, search

preferred[edit | edit source]

google earth which uses WGS84 as datum

The preferred coordinate system is WGS84 UTM coordinates.

Equirectangular[edit | edit source]

standard for global raster datasets, such as Celestia and NASA World Wind, because of the particularly simple relationship between the position of an image pixel on the map and its corresponding geographic location on Earth.

used by Three.js sphere

Spherical Mercator[edit | edit source]

Spherical Mercator is a de facto term used inside the OpenLayers community – and also the other existing Open Source GIS community – to describe the projection used by Google Maps, Microsoft Virtual Earth, Yahoo Maps, and other commercial API providers. This term is used to refer to the fact that these providers use a Mercator projection which treats the earth as a sphere, rather than a projection which treats the earth as an ellipsoid... In order to work well with the existing commercial APIs, many users who create data designed for use within Google Maps will also use this projection. One prime example is OpenStreetMap, whose raster map tiles are all projected into the ‘spherical mercator’ projection. Projections in GIS are commonly referred to by their “EPSG” codes... describing coordinates in meters in x/y... most spherical mercator maps use an extent of the world from -180 to 180 longitude, and from -85.0511 to 85.0511 latitude... this particular cutoff results in a perfect square of projected meters.

EPSG:3857 is a Spherical Mercator projection coordinate system popularized by web services such as Google and later OpenStreetMap.

HEALPix[edit | edit source]

HEALPix projection using GDAL#gdalwarp

GDAL does not support all projections... not supported: HEALPix