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surface_triangle
Returns the surface in steradians of the spherical triangle described by its
three vertices
Location in HEALPix directory tree:
src/f90/mod/pix_tools.f90
FORMAT call surface_triangle(
v1, v2, v3, surface
)
ARGUMENTS
| name&dimensionality |
kind |
in/out |
description |
|---|
| |
|
|
|
|
v1(3) |
DP |
IN |
cartesian vector pointing at the triangle first vertex. |
| v2(3) |
DP |
IN |
cartesian vector pointing at the triangle second vertex. |
| v3(3) |
DP |
IN |
cartesian vector pointing at the triangle third vertex. |
| surface |
DP |
OUT |
surface of the triangle in steradians. |
EXAMPLE:
use healpix_types
use pix_tools, only : surface_triangle
real(DP) :: surface, one = 1.0_dp
call surface_triangle((/1,0,0/)*one, (/0,1,0/)*one, (/0,0,1/)*one, surface)
print*, surface
Returns the surface in steradians of the triangle defined by the octant (x,y,z>0) : 1.5707963267948966
RELATED ROUTINESThis section lists the routines related to surface_triangle
-
pix2ang, ang2pix
- convert between angle and pixel number.
-
pix2vec, vec2pix
- convert between a cartesian vector and pixel number.
-
query_disc, query_polygon,
-
query_strip, query_triangle
- render the list of pixels enclosed
respectively in a given disc, polygon, latitude strip and triangle
Eric Hivon
2010-06-18
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