CreateGeodeticBuffer Method
Description
Creates a 'geodetic' buffer around items in a named list.
Syntax
Visual Basic |
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Public Function CreateGeodeticBuffer( _ ByVal list As String, _ ByVal datum As String, _ ByVal distance As Double, _ ByVal nPoints As Long _ ) As Integer |
Parameters
- list
- The named list to be scanned.
- datum
- The named datum to be used, e.g. WGS 84.
- distance
- The size of the buffer.
- nPoints
-
The number of points to be used when creating the buffer (see Remarks).
Remarks
- SIS builds the buffer by constructing a temporary set of circles along the route of the buffer. The distance argument must be a minimum of 1000m, below this the geodetic nature of the buffer is negligible.
- The nPoints argument determines how many points are used to construct each circle, thus defining the accuracy of the resulting buffer.
- The minimum value for the nPoints argument is 4, anything less than a square is not viable.
Available: GEO OD SISpy
Group:
Example
sis.CreateGeodeticBuffer ("Points", "WGS84", 1000.0,50)
Creates a geodetic buffer on all items in the named list called Points. The datum used is WGS84, but the buffer created is 1000m in size.