GetPrjScaleAtCentre Method
Description
Gets the scale at the centre of a named coordinate reference system.
Syntax
Visual Basic |
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Public Function GetPrjScaleAtCentre( _ ByVal prj As String _ ) As Double |
Parameters
- prj
- The coordinate reference system to query. This can be defined as:
- OGC URNs (eg 'urn:ogc:def:crs:OGC:1.3:CRS84')
- EPSG URNs (eg 'urn:ogc:def:crs:EPSG::27700')
- EPSG code strings (eg 'EPSG:27700')
- EPSG URLs (eg 'http://www.example.com/epsg#27700' or 'http://www.example.com/epsg.xml#27700')
- EPSG codes as a simple string (eg '27700')
- If blank, this will default to the current 'axes' CRS.
Return Type
The scale at the centre of a named coordinate reference system. This is necessary for interacting with the RenderTile method.
Remarks
Use this API if you want to calculate the RenderTile’s level parameter from map scale, or scale from level. You can also use it if you want to know the extent of the returned tile in coordinate reference system units. The calculation is slightly lengthy and must also take _OutputDPI& into account.
Available: GEO D OD OM SISpy
Group:
Example
sis.GetPrjScaleAtCentre ( "NAD27.Arizona East" )