MapWinGeoProc:Utils

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Utils

Summary

Utils provides a collection of methods ranging from file conversion to finding a point on a shape.

Structures

PartBounds A short structure with an integer of a part index and the first and last point in a shape.
The values are inclusive, so both begPoint and endPoint are in the part.


Functions

Area Computes the area of a polygon. For multi-part polygons, assume holes are counter-clockwise. This function has two overloaded versions.
AreaOfPart Calculates the area of a part, without taking into consideration any other aspects of the polygon.
Centroid This function returns a MapWinGIS.Point that represents the
mathematical "center of mass" for the MapWinGIS.Shape polygon.
Currently, shapes with multiple parts are supported, but treated
as island chains, not as shapes with holes. Shapes with holes
or shapes with self-intersecting parts will still return a value,
but it is not likely to be the correct value.
CentroidOfPart This function will calculate the centroid for a specific part of a
Mapwinshape. If the shape has only one part, the integer value
PartIndex will be ignored, and the centroid for the entire shape
will be calculated.
PointOnLine Finds if a point lies on a line or not.
AddPointToShape Not Implemented
Adds a given point to the line or polygon at the specified location.
RemovePointFromShape Not Implemented
Removes a point at ptLocation from the line or polygon shape.
FindNearestPointAndLoc Finds where the test point is closest to on a line or polygon shape and
returns the corresonding point and location and distance.
GridToShapefile Not Implemented, use MapWinGIS::Utils::GridToShapefile
Converts a grid to a shapefile.
ShapefileToGrid Converts a shapefile to a grid. This function has 3 overloads.
PointInPolygon Determines if a point lies within a polygon.
IsLeft on|right of an infinite line.
See: the January 2001 Algorithm "Area of 2D and 3D Triangles and Polygons"
at http://softsurfer.com/Archive/algorithm_0101/algorithm_0101.htm
wn_PnPoly Winding number test for point in polygon
PartIsSelfIntersecting Tests a specific part to ascertain if any two segements in the part intersect each other.
GetPartBounds This function verifies that PartIndex references a valid part in 'polygon'
and returns a structure containing the integer part index, beginning point
index for and ending point index for the part specified by PartIndex. It also
tests polygon to make sure that it is not null and is a polygon shapetype.
CheckPolygon Checks a shape object to ensure that it is a valid polygon.
Errors will throw exceptions.

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This page has been accessed 5,903 times. This page was last modified on 17 March 2008, at 09:21.