When they're displayed in Google Earth, they don't line up correctly (see attached). In the case of doing this, you would add the external WKID 3857 service into a map document and then alter the data frame to be WKID 4326 before publishing the map document. The basemap services provided by Esri (on ArcGIS Online, Data and Maps for Sever, and the Data Appliance for ArcGIS) use the WGS 1984 Web Mercator (Auxiliary Sphere) spatial reference (WKIDs 102100 or 3857). which is not only unsupported by Esri but also unpleasant in terms of visual quality and draw time performance. The only way I can really think of to "reproject" the WKID 3857 service to display correctly in Google Earth would be to reproject is intentionally by re-publishing it in your ArcGIS Server instance locally. Clearly in the case of WKID 3857, it doesn't. To do this in addbasemap, all you have to do is express the CRS your data are in: 6: ax db.plot() cx.addbasemap(ax, crsdb.crs) The result is then expressed in.
Sometimes it works, sometimes it doesn't. The same journey can be travelled in the oposite direction by leaving your data untouched and warping the tiles coming from the web. I've read recently that Google Earth doesn't always have the best reproject capabilities. Semiminor Axis: 6378137.000000000000000000ĪrcCatalog projection definition for "WGS 1984 Web Mercator (Auxiliary Sphere).prj" Spheroid: WGS_1984_Major_Auxiliary_Sphere In practice, how do you deal with the datum/projection transformation between WGS 84 Web Mercator / WGS84 Web Sphere Mercator and WGS 84 (ellipsoid). Another example here is that, if you look at the technical differences between these two WKIDs, you'll see they are inherently different despite the fact that they are so similar:ĪrcCatalog projection definition for "WGS 1984 Web Mercator.prj" The web map will be used to represent restaurants, hotels, and points of interests in downtown Vancouver, and will display information such as their address, phone number, and Web site.
To be specific, one example here is that the WKID 4326 uses decimal degrees and WKID 3857 uses meters. A 600 px by 600 px sized Adobe Illustrator document will be used and optimized to be displayed in a web browser.
However, the Web Mercator uses the spherical formulas at all scales whereas large-scale Mercator maps normally use the ellipsoidal form of the projection. It uses the same formulas as the standard Mercator as used for small-scale maps. The problem here is that the tiling schemes between WKID 4326 and WKID 3857 are different that is, the cached tiles differ between them in terms of tile width/height, scale thresholds at which the tiles were generated, X and Y origin, units, and technically even the coordinate system properties. Web Mercator is a slight variant of the Mercator projection, one used primarily in Web-based mapping programs.
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