VrOne/Python Programming

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PyVrGeom Class Reference

The VrOne/Python Geometry class includes helper coordinate geometry routines. More...

Members

• AziConv (Angle)
• AziNorth (x1, y1, x2, y2)
• AziSouth (x1, y1, x2, y2)
• AziEast (x1, y1, x2, y2)
• DeltaAng (Azi1, Azi2)
• Dist (x1, y1, x2, y2)
• ZenithAng (x1, y1, z1, x2, y2, z2)
• IsShorter (x1, y1, x2, y2, x3, y3, x4, y4)
• SlopeDist (x1, y1, z1, x2, y2, z2)
• Wind (MinX, MinY, MaxX, MaxY, TestX, TestY)
• InterY2D (X1, Y1, X2, Y2, X3, )
• InterX2D (Y3, X1, Y1, X2, Y2, )
• InterXY (x1, y1, z1, x2, y2, z2, z3)
• InterElev (x1, y1, z1, x2, y2, z2, x3, y3)
• InterZ3 (x1, y1, z1, x2, y2, z2, x3, y3, z3, x, y)
• RotPoint (BaseX, BaseY, x, y, Rot)
• OfsInt (LineX1, LineY1, LineX2, LineY2, PointX, PointY)
• PntToLine1 (LineX1, LineY1, LineX2, LineY2, PointX, PointY)
• PntToLine2 (LineX1, LineY1, LineZ1, LineX2, LineY2, LineZ2, PointX, PointY, PointZ)
• PntToLine3d (LineX1, LineY1, LineZ1, LineX2, LineY2, LineZ2, xp, yp, zp)
• CanLinesCross (MinX1, MinY1, MaxX1, MaxY1, MinX2, MinY2, MaxX2, MaxY2)
• IsPointOnLine (LineX1, LineY1, LineX2, LineY2, PointX, PointY)
• IsLineOnLine (x1, y1, x2, y2, x3, y3, x4, y4)
• OfsLine (Offset, OrgX1, OrgY1, OrgX2, OrgY2)
• DoLinesIntersect (Line1X1, Line1Y1, Line1X2, Line1Y2, Line2X1, Line2Y1, Line2X2, Line2Y2)
• CanLineCrossMbr (x1, y1, x2, y2, MinX, MinY, MaxX, MaxY)
• LineLineInt (Line1X1, Line1Y1, Line1X2, Line1Y2, Line2X1, Line2Y1, Line2X2, Line2Y2)
• BearBearInt (x1, y1, Azi1, x2, y2, Azi2)
• DistDistInt (x1, y1, dist1, x2, y2, dist2)
• BearDistInt (x1, y1, Azi1, x2, y2, Dist2)
• Circ3Pt (x1, y1, x2, y2, x3, y3)
• AngleIncr (Radius, Scale)
• AngleB (x1, y1, xc, yc, x2, y2)
• AngleDeflect (x1, y1, x2, y2, x3, y3)
• AziToBear (Azi)
• BearToAzi (Bear, Quad)
• FmtAzi (Azi, Accur, Direction)
• ParseDms (Dms)
• FmtBear (Bearing, Quadrant, Accur, FmtOpt)
• DoesMbrOverlap (DstStartX, DstStartY, DstEndX, DstEndY, SrcStartX, SrcStartY, SrcEndX, SrcEndY)
• GetOverlapArea (DstStartX, DstStartY, DstEndX, DstEndY, SrcStartX, SrcStartY, SrcEndX, SrcEndY)
• GetOverlapAreaD (DstStartX, DstStartY, DstEndX, DstEndY, SrcStartX, SrcStartY, SrcEndX, SrcEndY)

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Detailed Description

The Python VrOne Geometry Class contains useful coordinate geometry routines. The Python calls into this call use the same coordinate geometry routines used by VrOne. This class is provided to reduce user development time by using time-tested VrOne C++ routines

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Member Function Documentation

AziConv (Angle)

Converts an angle from (to) clockwise North to (from) counterclockwise from East.

Angle

AziNorth (x1, y1, x2, y2)

Computes North Azimuth from 2 coordinate positions.

x1	Point 1
y1	Point 1
x2	Point 2
y2	Point 2
returns	(ret)
	ret	Azimuth clockwise from North in radians.

AziSouth (x1, y1, x2, y2)

Computes South Azimuth from 2 coordinate positions.

x1	Point 1
y1	Point 1
x2	Point 2
y2	Point 2
returns	(ret)
	ret	Azimuth clockwise from South in radians.

AziEast (x1, y1, x2, y2)

Computes East Azimuth from 2 coordinate positions. This angle is normally used for text rotations.

x1	Point 1
y1	Point 1
x2	Point 2
y2	Point 2
returns	(ret)
	ret	Azimuth counterclockwise from East in radians.

DeltaAng (Azi1, Azi2)

Returns the delta angle between two azimuths. Always returns the acute angle.

Azi1	Azimuths 1 to compare (radians)
Azi2	Azimuths 2 to compare (radians)
returns	(ret)
	ret	Delta angle Example (in degrees): Azi1 = 350 Azi2 = 10 returns 20

Dist (x1, y1, x2, y2)

Computes the 2D distance between two points.

x1	Point 1
y1	Point 1
x2	Point 2
y2	Point 2
returns	(ret)
	ret	Distance.

ZenithAng (x1, y1, z1, x2, y2, z2)

Computes zenith angle from two 3D points.

x1	Point 1
y1	Point 1
z1	Point 1
x2	Point 2
y2	Point 2
z2	Point 1
returns	(ret)
	ret	Zenith angle (radians)

IsShorter (x1, y1, x2, y2, x3, y3, x4, y4)

Determines if line1 is shorter than line2

x1	Line 1 Point 1.
y1	Line 1 Point 1.
x2	Line 1 Point 2.
y2	Line 1 Point 2.
x3	Line 2 Point 1.
y3	Line 2 Point 1.
x4	Line 2 Point 2.
y4	Line 2 Point 2.
returns	(ret)
	ret	0 Line1 is shorter that Line2 1 Line1 is longer than or equal to Line2

SlopeDist (x1, y1, z1, x2, y2, z2)

Computes slope distance between two 3D points.

x1	Point 1
y1	Point 1
z1	Point 1
x2	Point 2
y2	Point 2
z2	Point 2
returns	(ret)
	ret	Slope distance

Wind (MinX, MinY, MaxX, MaxY, TestX, TestY)

 
 Returns the relationship of a point within a window
 
 | |
 9 | 1 | 5
 | |
 ----------------------- < MaxY
 |///////|
 8 |///0///| 4
 |///////|
 ----------------------- < MinY
 | |
 10 | 2 | 6
 | |
 ^ ^
 MinX MaxX
 

MinX	Window bounds
MinY	Window bounds
MaxX	Window bounds
MaxY	Window bounds
TestX	Test point
TestY	Test point

InterY2D (X1, Y1, X2, Y2, X3, )

Interpolates the unknown Y of three points.

X1	Point 1 X.
Y1	Point 1 Y.
X2	Point 2 X.
Y2	Point 2 Y.
X3	Known X of point 3.
returns	(UnknownY)
	UnknownY

InterX2D (Y3, X1, Y1, X2, Y2, )

Interpolates the unknown X of three points.

Y3	Known Y of point 3.
X1	Point 1.
Y1	Point 1.
X2	Point 2.
Y2	Point 2.
returns	(UnknownX)
	UnknownX

InterXY (x1, y1, z1, x2, y2, z2, z3)

Interpolates the XY position along a line based on the elevation

x1	Point one
y1	Point one
z1	Point one
x2	Point two
y2	Point two
z2	Point two
z3	Known elevation
returns	(x3, y3)
	x3	Return X
	y3	Return Y

InterElev (x1, y1, z1, x2, y2, z2, x3, y3)

Interpolates the unknown elevation of three points.

x1	Point one
y1	Point one
z1	Point one
x2	Point two
y2	Point two
z2	Point two
x3	Known x of third point.
y3	Known y of third point.
returns	(z3)
	z3	Unknown elevation of third point. If there is no distance between points one and two then Z3 returns with the elevation of Z1.

InterZ3 (x1, y1, z1, x2, y2, z2, x3, y3, z3, x, y)

Interpolates a Z from a 3D surface defined by a triangle.

x1	Point one on triangle
y1	Point one on triangle
z1	Point one on triangle
x2	Point two on triangle
y2	Point two on triangle
z2	Point two on triangle
x3	Point three on triangle
y3	Point three on triangle
z3	Point three on triangle
x	Point to interpolate Z for.
y	Point to interpolate Z for.
returns	(z)
	z	Return elevation.

RotPoint (BaseX, BaseY, x, y, Rot)

Rotates a point about a base point.

BaseX	Base point.
BaseY	Base point.
x	Point to be rotated.
y	Point to be rotated.
Rot	Rotation clockwise in radians.
returns	(x, y)
	x	Return point x.
	y	Return point y.

OfsInt (LineX1, LineY1, LineX2, LineY2, PointX, PointY)

Computes the offset and distance from a point to a line.

LineX1	Point one of the line.
LineY1	Point one of the line.
LineX2	Point two of the line.
LineY2	Point two of the line.
PointX	Point
PointY	Point
returns	(Offset, Distance)
	Offset	Resulting offset with the following conditions: Positive - Point is to the right of the line. Negative - Point is to the left of the line.
	Distance	Resulting distance from point to line.

PntToLine1 (LineX1, LineY1, LineX2, LineY2, PointX, PointY)

Snaps a point to a line 2D.

LineX1	Point one of the line.
LineY1	Point one of the line.
LineX2	Point two of the line.
LineY2	Point two of the line.
PointX	Point to snap to line.
PointY	Point to snap to line.
returns	(ret, xr, yr, Dist)
	ret	0=Point falls between line endpoints 1=Point falls below the line * x----------> 2=Point falls above the line x---------> *
	xr	Point x snapped to line.
	yr	Point y snapped to line.
	Dist	Return distance (optional) Positive - Point is to the right of the line. Negative - Point is to the left of the line.

PntToLine2 (LineX1, LineY1, LineZ1, LineX2, LineY2, LineZ2, PointX, PointY, PointZ)

Snaps a point to a line 2D but interpolates a Z.

LineX1	Point one of the line.
LineY1	Point one of the line.
LineZ1	Point to snap to line.
LineX2	Point two of the line.
LineY2	Point two of the line.
LineZ2	Point to snap to line.
PointX	Point to snap to line.
PointY	Point to snap to line.
PointZ	Point to snap to line.
returns	(ret, xr, yr, zr, Dist)
	ret	0=Point falls between line endpoints 1=Point falls below the line * x----------> 2=Point falls above the line x---------> *
	xr	Point x snapped to line.
	yr	Point y snapped to line.
	zr	Interpolated z on line.
	Dist	Return distance (optional) Positive - Point is to the right of the line. Negative - Point is to the left of the line.

PntToLine3d (LineX1, LineY1, LineZ1, LineX2, LineY2, LineZ2, xp, yp, zp)

Snaps a 3D point to a 3D line using doubles. This is a true 3D computation

LineX1	Point one of the line.
LineY1	Point one of the line.
LineZ1	Point one of the line.
LineX2	Point two of the line.
LineY2	Point two of the line.
LineZ2	Point one of the line.
xp	Point to snap to line.
yp	Point to snap to line.
zp	Point to snap to line.
returns	(ret, xr, yr, zr, Dist)
	ret	0=Point falls between line endpoints 1=Point falls below the line * x----------> 2=Point falls above the line x---------> *
	xr	Point x snapped to line.
	yr	Point y snapped to line.
	zr	Point z snapped to line (interpolated).
	Dist	Return distance from xp,yp,zp to line intersection (optional)

CanLinesCross (MinX1, MinY1, MaxX1, MaxY1, MinX2, MinY2, MaxX2, MaxY2)

Determines if it is possible for two lines to cross by checking their MBRs.

MinX1	Minimum coordinate of MBR 1.
MinY1	Minimum coordinate of MBR 1.
MaxX1	Maximum coordinate of MBR 1.
MaxY1	Maximum coordinate of MBR 1.
MinX2	Minimum coordinate of MBR 2.
MinY2	Minimum coordinate of MBR 2.
MaxX2	Maximum coordinate of MBR 2.
MaxY2	Maximum coordinate of MBR 2.
returns	(ret)
	ret	TRUE - Lines could cross. FALSE - No way Man.

IsPointOnLine (LineX1, LineY1, LineX2, LineY2, PointX, PointY)

Determines if a point lies on a line.

LineX1	Point one of the line.
LineY1	Point one of the line.
LineX2	Point two of the line.
LineY2	Point two of the line.
PointX	Test point.
PointY	Test point.
returns	(ret)
	ret	0 - Point is not on line. 1 - Point is on line and not between line endpoints. 2 - Point is on line between line endpoints. 3 - Point is the same as one of the endpoints.

IsLineOnLine (x1, y1, x2, y2, x3, y3, x4, y4)

 
 Determines if line2 lies on line1.
 I.e.
 
 x3y3 x4y4
 *-----*=-=-=-=-=-=-=-=-=*------* = TRUE
 x1y1 x2y2
 
 x3y3 x4y4
  *-------------*=-=-=-=-=-=-=-=-=* = TRUE
 x1y1 x2y2
 
 x3y3 x4y4
 *-------------*=-=-=-=-=-=-*====* = FALSE 
 x1y1 x2y2
 
 x3y3 x4y4
  *==================*
 *--------------------------------* = FALSE 
 x1y1 x2y2

x1	Point one of line 1.
y1	Point one of line 1.
x2	Point two of line 1.
y2	Point two of line 1.
x3	Point one of line 2.
y3	Point one of line 2.
x4	Point two of line 2.
y4	Point two of line 2.
returns	(ret)
	ret	0 - Lines do not lie on top of each other. 1 - Lines lie on top of each other.

OfsLine (Offset, OrgX1, OrgY1, OrgX2, OrgY2)

Offsets a two point line

Offset	Distance to offset new line from original. negative - Offset to left. positive - Offset to right.
OrgX1	Point 1 of original line to be offset.
OrgY1	Point 1 of original line to be offset.
OrgX2	Point 2 of original line to be offset.
OrgY2	Point 2 of original line to be offset.
returns	(NewX1, NewY1, NewX2, NewY2)
	NewX1	Point 1 of new line.
	NewY1	Point 1 of new line.
	NewX2	Point 2 of new line.
	NewY2	Point 2 of new line.

DoLinesIntersect (Line1X1, Line1Y1, Line1X2, Line1Y2, Line2X1, Line2Y1, Line2X2, Line2Y2)

Line to line intersection.

Line1X1	Line 1 Point 1
Line1Y1	Line 1 Point 1
Line1X2	Line 1 Point 2
Line1Y2	Line 1 Point 2
Line2X1	Line 2 Point 1
Line2Y1	Line 2 Point 1
Line2X2	Line 2 point 2
Line2Y2	Line 2 point 2
returns	(ret)
	ret	TRUE=Lines intersect,FALSE=Lines don't intersect

CanLineCrossMbr (x1, y1, x2, y2, MinX, MinY, MaxX, MaxY)

Determine if a line segment can possibly cross an MBR area.

x1	Line segment coordinates
y1	Line segment coordinates
x2	Line segment coordinates
y2	Line segment coordinates
MinX	MBR extents
MinY	MBR extents
MaxX	MBR extents
MaxY	MBR extents

LineLineInt (Line1X1, Line1Y1, Line1X2, Line1Y2, Line2X1, Line2Y1, Line2X2, Line2Y2)

Line to line intersection.

Line1X1	Line 1 Point 1
Line1Y1	Line 1 Point 1
Line1X2	Line 1 Point 2
Line1Y2	Line 1 Point 2
Line2X1	Line 2 Point 1
Line2Y1	Line 2 Point 1
Line2X2	Line 2 point 2
Line2Y2	Line 2 point 2
returns	(IntX, IntY, IntFlag)
	IntX	Intersection point of line1 and line2
	IntY	Intersection point of line1 and line2
	IntFlag	A A A -------> -------> -------> | | | | B | B | B | | | V V V 12 4 6 | A | A | | -------> ---+---> ------->| B | | | V V V 8 0 2 | | | | B | B | B | | | V A V A V -------> -------> -------> 9 1 3 A A -------> -------> B AB -------> ----->-> . B 15 15 15

BearBearInt (x1, y1, Azi1, x2, y2, Azi2)

Bearing - bearing intesection.

x1	Point 1
y1	Point 1
Azi1	Azimuth from point 1 in radians from North.
x2	Point 2
y2	Point 2
Azi2	Azimuth from point 2 in radians from North.
returns	(IntX, IntY, Stus)
	IntX	Intersection point x.
	IntY	Intersection point y.
	Stus	Status - 0 - OK -1 Lines are parallel and no solution computed. -2 Point 1 and point 2 are the same.

DistDistInt (x1, y1, dist1, x2, y2, dist2)

Computes distance - distance intersection.

x1	Point 1
y1	Point 1
dist1	Distance 1
x2	Point 2
y2	Point 2
dist2	Distance 2
returns	(ret, IntX, IntY)
	ret	0=Ok -1=Could not compute intersection. Points 1 and 2 are probably too far apart. Computes the solution clockwise direction from point 1 to point 2. To compute the other solution, call to routine with the points and distances reversed.
	IntX	Intersection point.
	IntY	Intersection point.

BearDistInt (x1, y1, Azi1, x2, y2, Dist2)

Computes bearing - distance intersection. To compute the other solution call with azi reversed distances reversed.

x1	Starting point of line
y1	Starting point of line
Azi1	Azimuth of line (Decimal radians from North).
x2	Point to test distance intersection with
y2	Point to test distance intersection with
Dist2	Distance from x2, y2
returns	(ret, IntX, IntY)
	ret	0 if successfull, -1 if no intersection possible.
	IntX	Intersection point X (if possible)
	IntY	Intersection point Y (if possible)

Circ3Pt (x1, y1, x2, y2, x3, y3)

Computes the center of a circle defined by 3 points along edge.

x1	Point 1 on arc.
y1	Point 1 on arc.
x2	Point 2 on arc.
y2	Point 2 on arc.
x3	Point 3 on arc.
y3	Point 3 on arc.
returns	(ret, CenX, CenY, Rad)
	ret	0=Ok -1=Error, do not use results.
	CenX	Return center point of circle X.
	CenY	Return center point of circle Y.
	Rad	Return radius.

AngleIncr (Radius, Scale)

Returns the angle increment for drawing a smooth circular arc.

Radius	Radius of circle or arc in user units.
Scale	Draw scale in ratio form (1:n). To decrease (increase the number of points on the arc) the result, make 24000 larger. ___________________________ / radius * sqrt(2) * 24000 / ------------------------ \/ SCALE
returns	(ret)
	ret	Angle increment for drawing a smooth circular arc

AngleB (x1, y1, xc, yc, x2, y2)

Computes angle B of a triangle from three coordinate positions.

x1	Point one. Point on arc.
y1	Point one. Point on arc.
xc	Center point at angle B.
yc	Center point at angle B.
x2	Point two. Point on arc.
y2	Point two. Point on arc.
returns	(ret)
	ret	Angle n radians (0-PI).

AngleDeflect (x1, y1, x2, y2, x3, y3)

Computes the deflection angle from three coordinate postions.

x1	Point 1
y1	Point 1
x2	Point 2
y2	Point 2
x3	Point 3
y3	Point 3
returns	(ret)
	ret	Angle n radians (0-PI).

AziToBear (Azi)

Converts an azimuth to a bearing and quadrant code

Azi	Azimuth to convert (decimal radians from the North) if azi is not in the range of 0-pi radians (0-360 degrees) it will be forced into range. NOTE : Conversion of angles from h.ms degrees <-> decimal radians. azi := dec_deg(azi) / conv; hms degrees -> dec radians azi := hms (azi*conv); dec radians -> hms degrees
returns	(Bear, Quadrant)
	Bear	Return bearing (decimal radians)
	Quadrant	Return quadrant code (1-4). If azi is not in the range of 0-pi radians (0-360 degrees) it will be forced into range.

BearToAzi (Bear, Quad)

Converts a bearing to an azimuth

Bear	Bearing in decimal radians.
Quad	Quadrant code (1-4).
returns	(Azi)
	Azi	Return azimuth in decimal radians from the north. If quad is out of range of 1-4 or if bear is out of the range of 0-1.5707963271 radians (0-90 degrees) then azi returns 0.0.

FmtAzi (Azi, Accur, Direction)

Formats an azimuth for display in the form ddd mm ss.s

Azi	Azimuth to be formatted (radians from the North)
Accur	Number of decimal places for seconds
Direction	0 = Return azimuth from North. 1 = Return azimuth from South.
returns	(AziStrg)
	AziStrg	Return string

ParseDms (Dms)

Parses angle expressed in degrees minutes seconds.

Dms	Angle in the form of ddd.mmsec
returns	(Deg, Min, Sec)
	Deg	Return degress
	Min	Return minutes
	Sec	Return seconds

FmtBear (Bearing, Quadrant, Accur, FmtOpt)

Formats a bearing in the form of q hh-mm-ss.tt q

Bearing	Bearing in decimal radians.
Quadrant	Quadrant code (1-4).
Accur	Decimal accuracy of seconds.
FmtOpt	Bearing format option. 0 - N dd-mm-ss E 1 - N dd\mm'ss"E If Bearing is out of the range of 0-pi/2 radians (0-90 degrees) then ? **-**-** ? is returned. If quad is out of the range of 1-4 then and Bearing is in range then ? nn-nn-nn ? is returned.
returns	(BearStrg)
	BearStrg	Return bearing string.

DoesMbrOverlap (DstStartX, DstStartY, DstEndX, DstEndY, SrcStartX, SrcStartY, SrcEndX, SrcEndY)

Finds the overlap area of the source rectangle to the destination rectangle. Integer based.

DstStartX	Destination rectangle
DstStartY	Destination rectangle
DstEndX	Destination rectangle
DstEndY	Destination rectangle
SrcStartX	Source rectangle
SrcStartY	Source rectangle
SrcEndX	Source rectangle
SrcEndY	Source rectangle
returns	(ret)
	ret	0 = Areas overlap, -1 = Areas don't overlap

GetOverlapArea (DstStartX, DstStartY, DstEndX, DstEndY, SrcStartX, SrcStartY, SrcEndX, SrcEndY)

Finds the overlap area of the source rectangle to the destination rectangle. Integer based.

DstStartX	Destination rectangle
DstStartY	Destination rectangle
DstEndX	Destination rectangle
DstEndY	Destination rectangle
SrcStartX	Source rectangle
SrcStartY	Source rectangle
SrcEndX	Source rectangle
SrcEndY	Source rectangle
returns	(ret, DstOverStartX, DstOverStartY, SrcOverStartX, SrcOverStartY, OverWdt, OverHgt)
	ret	0 = Areas overlap, -1 = Areas don't overlap
	DstOverStartX	Start of overlap area in destination rectangle
	DstOverStartY	Start of overlap area in destination rectangle
	SrcOverStartX	Start of overlap area in source rectangle
	SrcOverStartY	Start of overlap area in source rectangle
	OverWdt	Width of overlap area
	OverHgt	Height of overlap area

GetOverlapAreaD (DstStartX, DstStartY, DstEndX, DstEndY, SrcStartX, SrcStartY, SrcEndX, SrcEndY)

Finds the overlap area of the source rectangle to the destination rectangle. Double based.

DstStartX	Destination rectangle
DstStartY	Destination rectangle
DstEndX	Destination rectangle
DstEndY	Destination rectangle
SrcStartX	Source rectangle
SrcStartY	Source rectangle
SrcEndX	Source rectangle
SrcEndY	Source rectangle
returns	(ret, DstOverStartX, DstOverStartY, SrcOverStartX, SrcOverStartY, OverWdt, OverHgt, OverlayMode)
	ret	0 = Areas overlap, -1 = Areas don't overlap
	DstOverStartX	Start of overlap area in destination rectangle
	DstOverStartY	Start of overlap area in destination rectangle
	SrcOverStartX	Start of overlap area in source rectangle
	SrcOverStartY	Start of overlap area in source rectangle
	OverWdt	Width of overlap area
	OverHgt	Height of overlap area
	OverlayMode	Optional. Returns primary side that is overlapped. LEFT=0,RIGHT=1,TOP=2,BOTTOM=3