diff options
Diffstat (limited to 'stsci/sphere/great_circle_arc.py')
| -rw-r--r-- | stsci/sphere/great_circle_arc.py | 34 |
1 files changed, 31 insertions, 3 deletions
diff --git a/stsci/sphere/great_circle_arc.py b/stsci/sphere/great_circle_arc.py index d5e78f2..0d60389 100644 --- a/stsci/sphere/great_circle_arc.py +++ b/stsci/sphere/great_circle_arc.py @@ -71,7 +71,7 @@ def _fast_cross(a, b): """ if HAS_C_UFUNCS: return math_util.cross(a, b) - + cp = np.empty(np.broadcast(a, b).shape) aT = a.T bT = b.T @@ -83,9 +83,11 @@ def _fast_cross(a, b): return cp + def _cross_and_normalize(A, B): if HAS_C_UFUNCS: - return math_util.cross_and_norm(A, B) + with np.errstate(invalid='ignore'): + return math_util.cross_and_norm(A, B) T = _fast_cross(A, B) # Normalization @@ -154,7 +156,7 @@ def intersection(A, B, C, D): """ if HAS_C_UFUNCS: return math_util.intersection(A, B, C, D) - + A = np.asanyarray(A) B = np.asanyarray(B) C = np.asanyarray(C) @@ -224,6 +226,14 @@ def length(A, B, degrees=True): A = np.asanyarray(A) B = np.asanyarray(B) + A2 = A ** 2.0 + Al = np.sqrt(A2[..., 0] + A2[..., 1] + A2[..., 2]) + B2 = B ** 2.0 + Bl = np.sqrt(B2[..., 0] + B2[..., 1] + B2[..., 2]) + + A = A / np.expand_dims(Al, 2) + B = B / np.expand_dims(Bl, 2) + dot = inner1d(A, B) dot = np.clip(dot, -1.0, 1.0) with np.errstate(invalid='ignore'): @@ -257,9 +267,27 @@ def intersects(A, B, C, D): """ with np.errstate(invalid='ignore'): intersections = intersection(A, B, C, D) + return np.isfinite(intersections[..., 0]) +def intersects_point(A, B, C): + """ + Returns True if point C is along the great circle arc AB. + """ + # Check for exact match at the endpoint first + if np.any(np.all(A == C, axis=-1)): + return True + + total_length = length(A, B) + left_length = length(A, C) + right_length = length(C, B) + + length_diff = np.abs((left_length + right_length) - total_length) + + return np.any(length_diff < 1e-8) + + def angle(A, B, C, degrees=True): """ Returns the angle at *B* between *AB* and *BC*. |