Purpose
Returns a region object that represents a buffer region (the area within a specified buffer distance of an existing object). You can call this function from the MapBasic window in MapInfo Pro.
Syntax
CartesianBuffer( inputobject, resolution, width, unit_name )inputobject is an object expression.
resolution is a SmallInt value representing the number of nodes per circle at each corner.
width is a float value representing the radius of the buffer; if width is negative, and if inputobject is a closed object, the object returned represents an object smaller than the original object.
unit_name is the name of the distance unit (e.g., "mi" for miles, "km" for kilometers) used by width.
Return Value
Region Object
Description
The CartesianBuffer() function returns a region representing a buffer and operates on one single object at a time.
To create a buffer around a set of objects, use the Create Object statement As Buffer. If width is negative, and the object is a linear object (line, polyline, arc) or a point, then the absolute value of width is used to produce a positive buffer.
The CartesianBuffer() function calculates the buffer by assuming the object is in a flat projection and using the width to calculate a cartesian distance calculated buffer around the object.
If the inputobject is in a Latitude/Longitude Projection, then Spherical calculations will be used regardless of the Buffer function used.
Example
The following program creates a line object, then creates a buffer region that extends 10 miles surrounding the line.
Dim o_line, o_region As Object
o_line = CreateLine(-73.5, 42.5, -73.6, 42.8)
o_region = CartesianBuffer( o_line, 20, 10, "mi") See Also:
Buffer() function, Creating Map Objects, Set Buffer Version statement