Description

A standard interface to the pclip (polygon/polygon intersection) standalone engine executable.

Standard Definitions

point_list:

A list of points, defined as: [[x0, y0, z0], ..., [xN, yN, zN]].

coded_point_list:

A tuple containing two items: the first item is a code (string), the second is the corresponding point_list. This data type is intended to mimic the srv file format. The code should match with an accompanying parameter file (survey code file). For example, ['BENCH', [[x0, y0, z0], ..., [xN, yN, zN]]]

face_list:

All face lists are described such that the first index indicates how many faces are in the face. For example,

[3, 1, 2, 3, 3, 4, 5, 6]

States that there are 3 vertexes in the first face, and those vertexes are 1, 2, 3. Then the next face contains 3 vertexes, which are 4, 5, 6. This may seem a bit confusing, but using this structure buys us some definite efficiencies. Note that all faces in MineSight® products have 3 vertexes.

Functions

pclip(pointLists1, pointLists2, oper1, oper2, int, union, diff, f, R, dat, debug)

Polygon/Polygon intersection program. The function returns either the intersection, union, or difference of the polygons.

Arguments:

pointLists1 : a list of point_lists

Point lists of the polygon set #1

pointLists2 : a list of point_lists

Point lists of the polygon set #2

oper1 : string

A pre-processing operation over input polygon set #1 to be performed before other calculations. Either 'n', 's', or 'c', where:

n=No preprocessing (DEFAULT); s=Separate polygons into independent sets; c=Combine all polygons in one.

oper2 : string

A pre-processing operation over input polygon set #2. See above.

int : integer

Output intersection of input polygons. Set value to 1 to turn on this option.

union : integer

Output union of input polygons. Set value to 1 to turn on this option.

diff : integer

Output difference of input polygons. Set value to 1 to turn on this option.

f : integer

Validate polygons before intersection. Set to either 0 or 1, where:

0 = make external and internal polygons to have opposite direction (DEFAULT); 1 = use original direction of polygons.

R : integer

Reverse polygons (external oriented clockwise). Set value to 1 to turn on this option.

dat : string

Define a directory with input files.

debug : integer

Debug option will output the command string used to call the engine executable and will relay any output messages from the engine. Set value to 1 to turn on this option.

Returns:

A list of point_lists (see Standard Definitions).

Example:

from grail.engines import pclip

polygon1 = [[2.0, 0.0, 3895.0],[4.0, 0.0, 3895.0],[4.0, 2.0, 3895.0],[2.0, 2.0, 3895.0],[2.0, 0.0, 3895.0]]
polygon2 = [[1.0, 0.0, 3895.0],[3.0, 0.0, 3895.0],[3.0, 2.0, 3895.0],[1.0, 2.0, 3895.0],[1.0, 0.0, 3895.0]]

#use keyword arguments in function call
listOfPointLists = pclip.pclip(pointLists1=[polygon1], pointLists2=[polygon2], int=1, R=1)
intersectionPolygon = listOfPointLists[0]