ex03_polygon_conversion
This example localizes a three-dimensional merge with a simplified South America polygon. The requested outline is not strictly xy-monotone, so it must be converted before BLEND can define the horizontal window. The primary and secondary cubes contain constant values of 8 and 2, respectively.
The mergefile contains:
primary secondary south_america.txt 20/80 cosine/cosine/cosine 0.49
secondary - - - - -
-ME replaces the requested polygon with its strict xy-monotone envelope.
Appending +w writes that envelope to south_america_monotone.txt. The
horizontal footprint is extruded through the specified 20/80 z interval, and
the 0.49 cosine taper is applied at both ends of all three dimensions.
Panels (a-d) show the inputs, requested polygon, and converted envelope. Panels
(e-f) show the horizontal weight and merged result at z = 50. Panels (g-h)
show vertical sections along latitude -20; the horizontal lines mark
the z support. In the horizontal weight panel, blue marks the requested polygon
and orange marks the converted envelope.
Because both inputs are constant, the merged field is 2 + 6 * weight. The
script verifies this relationship in both the horizontal and vertical views.
Run:
./ex03_polygon_conversion.sh
The script creates south_america_monotone.txt,
ex03_polygon_conversion.png, and ex03_polygon_conversion.pdf.
Figures
