Cesium: different projections

[deRightDirection]

i assume the cesium globe needs 4326 as projection for displaying data.

i tried one ArcGIS service which has a different projection and is not drawn on the cesium globe. I did the same exercise with a service in 4326 and perfectly drawn around the globe.

my conclusion is that the projections matters and of course it does.
does the Cesium.ArcGisMapServerImageryProvider has a property where i can set the output spatial reference? I assume the Cesium object uses exportmap-function for retrieving the picture to be drawn on the globe.

In the Esri ArcGIS Rest interface there is a property for exportmap (imageSR) where you can set the requested spatial reference. I think if i can use this property inside the Cesium-object the issue I have right now will be resolved.

[hpinkos]

Hello @MannusEtten
I'm not exactly sure what problem you are seeing. We recently fixed a bug for ArcGisMapServerImageryProvider where using a web mercator projection was resulting in a crash. This will be fixed in the next release.
Is that the problem you are having?
Thanks!

[deRightDirection]

no that is not the problem, the problem is pretty easy:

• use a mapservice without a web mercator or wgs84 projection and there is nothing to see on the cesium-globe

[hpinkos]

@MannusEtten Cesium currently only supports web mercator and WGS84. Do you have a way to re-project your imagery? Projecting it to WGS84 would be ideal.

[pjcozzi]

CC #2084 and #3824

[pjcozzi]

EPSG:3395 was requested in #2084

[pjcozzi]

OSGB36 was requested in #3824

[OmarShehata]

There seems to be a lot of interest in different projections/ellipsoids lately.

• GRS80 Ellipsoid and EPSG 2180 on the forum.
• ETRS89 on the forum.
• EPSG:4490 on the forum.

[nmtoken]

Cesium currently only supports web mercator and WGS84

Can you clarify what is meant here by WGS84?

WGS84 is an ellipsoid, not a projection.

Does it mean any projection that uses the WGS84 ellipsoid? or does it mean a specific projection that uses that ellipsoid, such as epsg:4326?

Just for pendants:

WGS 84 (that spelling) is the name of an ellipsoid (EPSG::7030), the name of a geodetic coordinate reference system (EPSG::4326), and the alias of a datum (EPSG::6326), official name World Geodetic System 1984.

WGS84 (no space) is the alias of the ellipsoid (EPSG::7030).

[OmarShehata]

@nmtoken I think that means specifically EPSG:4326 but @hpinkos can correct me if I'm wrong.

[nmtoken]

So just double-checking (using the EPSG WKT definition):

GEODCRS["WGS 84",
  DATUM["World Geodetic System 1984",
    ELLIPSOID["WGS 84",6378137,298.257223563,LENGTHUNIT["metre",1.0]]],
  CS[ellipsoidal,2],
    AXIS["latitude",north,ORDER[1]],
    AXIS["longitude",east,ORDER[2]],
    ANGLEUNIT["degree",0.01745329252],
  ID["EPSG",4326]]

Cesium expects coordinates in Lat/Lon order?

[GatorScott]

Cesium supports map image data in Web Mercator or Plate Carree/Equirectangular projections. This issue captures community interest in having native support for other projections.

Coordinate data must be provided in x/y/z (lon/lat/height) order.

[nmtoken]

Coordinate data must be provided in x/y/z (lon/lat/height) order.

Thanks@GatorScott so explicitly that's not EPSG:4326

[nmtoken]

This issue captures community interest in having native support for other projections.

As I have a web service that doesn't support CRS:84 (it's not a WMS), it would be nice if Cesium could indeed support EPSG:4326.

[OmarShehata]

Came up again on the forum for displaying imagery in EPSG:26917 (NAD83 / UTM zone 17N)

[OmarShehata]

WKID 4490 requested here https://github.com/AnalyticalGraphicsInc/cesium/issues/8522.