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How to check the geographic coordinate system in ArcMap?
It is possible to check the geographic coordinate system currently used by the data by opening ArcMap and loading the data layer. Right-click on the layer and click Properties. In the Layer Properties dialog box, select the Source tab.
Why do datasets do not line up when added to ArcMap?
After adding several datasets to an ArcMap Data Frame, features in some layers do not align correctly with other layers. When adding data to ArcMap, the application reads the coordinate system (projection) information stored with the dataset.
Why is Esri not working on Google Maps?
Search on Esri Community Submit to ArcGIS Ideas Spatial features from ArcGIS Server may not align correctly with the maps in Google Maps or Microsoft Virtual Earth when overlaid using the ESRI JavaScript extensions. The cause may be geographic (datum) transformation issues.
Why is the data not lining up with the basemap?
For some reason the data was not lining up with the basemap and I can’t remember how I got it to work in the end – mostly a lot of trial and error. Unfortunately I moved the Excel source so when I reopened it later it had the whole red exclamation mark deal next to the data.
Why is ArcGIS Server not working with Google Maps?
Spatial features from ArcGIS Server may not align correctly with the maps in Google Maps or Microsoft Virtual Earth when overlaid using the ESRI JavaScript extensions. The cause may be geographic (datum) transformation issues. These issues are usually most evident at the local scale, such as a local street map.
Where to find WGS 1984 Web Mercator coordinate system?
For ArcGIS Server 9.3 where Service Pack 1 has been applied, the WGS 1984 Web Mercator coordinate system can be used to transform the data. This projection is located in the coordinate systems list under Predefined – Projected Coordinate Systems – World.
How does a ground based coordinate system work?
Then the ground-based coordinate system is tied to a projection-based system such as State Plane, using a scale factor and optional translation/rotation. This system works well, as long as the project extents do not extend very far.
What kind of projection does Google Maps use?
These issues are usually most evident at the local scale, such as a local street map. Google Maps and Microsoft Virtual Earth use a Mercator projection based on the World Geodetic System (WGS) 1984 geographic coordinate system (datum).
What happens when data is based on a different coordinate system?
If the data are based on a different geographic coordinate system, such as the North American Datum of 1927 (NAD27), ED 50, Amersfoort, or Tokyo; then misalignment may be quite noticeable at the local scale.