The choice between a global or local scene depends on the spatial reference of your data, the layer types, and what you are trying to achieve in your scene.
Global scene
Use Global scene if any of the following applies:
- Your data is in a geographic coordinate system or the Web Mercator (Auxiliary Sphere) (WKID: 3857). Global Scenes support all geographic coordinate systems (GCS) and one projected coordinate system (PCS) which is the Web Mercator. If you create a map using Web Mercator, data is reprojected to WGS84 (WKID: 4326) and displayed on the WGS84 ellipsoid.
- You want to show global-scale data. Global scenes display your spatial content on an ellipsoid.
Geographic coordinate systems are based on a three-dimensional ellipsoidal or spherical surface, and locations are defined using angular measurements, usually in decimal degrees, measuring degrees of longitude (x-coordinates) and degrees of latitude (y-coordinates). See Spatial references for more information about geographic coordinate systems.
Local scene
Use Local scene if any of the following applies:
- Your data is in a projected coordinate system or WGS84 (WKID: 4326) or China Geodetic Coordinate System 2000 (WKID: 4490) geographic coordinate systems. Local scenes support all projected coordinate system and two geographic coordinate systems, which are WGS84 and CGCS2000. If you create a map using the spatial reference of one of these geographic coordinate systems in a local scene, data is reprojected to Plate Carrée (WKID: 32662) to display the data on a planar surface.
- You want to visualize a smaller, regional area.
- You want to make a precise measurement of length or area. Projected coordinate systems are planar systems that use map projections to convert geographic locations in angular (longitude, latitude) coordinates to map locations in Cartesian (x, y) coordinates. See Spatial references for more information about projected coordinate systems.
Map extent
In a local scene, you can clip the basemap and layers to the custom extent of your view. This is useful for increasing performance, focusing on key elements of your project, and interacting with underground layers.
The map extent is defined by a series of bounding coordinates that delineate the area of the map or scene that you want to work with. You can select either a circular or rectangular shape and define values for the dimensions.
Values for extent
- X (Longitude): Specifies the east–west position of the center of the extent. A projected position value for projected coordinate systems or a longitude value for geographic coordinate systems.
- Y (Latitude): Specifies the north–south position of the center of the extent. A projected position value for projected coordinate systems or a latitude value for geographic coordinate systems.
- Spatial Reference: The spatial reference Well-Known ID (WKID) for the horizontal (geographic or projected) and optional vertical (gravity-related or ellipsoidal) coordinate systems.
- X (Width): A side-to-side measurement of the extent. It is a radius value when the extent shape is a circle. The units depend on the spatial reference.
- Y (Height): A base-to-top measurement of the extent. The units depend on the spatial reference.
To configure an extent:
- Click on the Map tab, and make sure the Map Type is Local.
- Under the Map Extent section, check the Is Extent Enabled checkbox.
- In the Geographic Center, set the position values and spatial reference WKIDs.
- Select an Extent Shape from the drop-down and set the dimension values.
Vertical Coordinate System
Vertical coordinate systems can be used in your scene to define the origin for height or depth values. These systems use linear units (usually in meters) for gravity-related or ellipsoidal heights. If no vertical coordinate system is specified for an ArcGIS Map, the unit used depends on the horizontal coordinate system; meters are used for geographic coordinate systems; otherwise, the same unit from the projected coordinate system is used. See Spatial references for more information about vertical coordinate systems.