Improve overlapsTract and use sphgeom

Improve overlapsTract as follows:
- Update to use sphgeom instead of geom
  (this was the only routine using geom).
  Note that convexHull can no longer return False,
  but it should never fail anyway (if we find it does
  fail we'll have to move the call into a try/except).
- Use new method skymap.TractInfo.getOuterSkyPolygon
- Call wcs.pixelToSky once on a list of points

python/lsst/meas/base/forcedPhotCcd.py

@@ -29,7 +29,7 @@
 import lsst.afw.geom
 import lsst.afw.image
 import lsst.afw.table
-from lsst.geom import convexHull
+import lsst.sphgeom
 
 from .forcedPhotImage import ForcedPhotImageTask, ForcedPhotImageConfig
 
@@ -110,23 +110,19 @@ def overlapsTract(tract, imageWcs, imageBox):
     @param imageBox: Bounding box for image
     @return bool
     """
-    tractWcs = tract.getWcs()
-    tractCorners = [tractWcs.pixelToSky(lsst.afw.geom.Point2D(coord)).getVector() for
-                    coord in tract.getBBox().getCorners()]
-    tractPoly = convexHull(tractCorners)
+    tractPoly = tract.getOuterSkyPolygon()
 
+    imagePixelCorners = lsst.afw.geom.Box2D(imageBox).getCorners()
     try:
-        imageCorners = [imageWcs.pixelToSky(lsst.afw.geom.Point2D(pix)) for pix in imageBox.getCorners()]
+        imageSkyCorners = imageWcs.pixelToSky(imagePixelCorners)
     except lsst.pex.exceptions.LsstCppException as e:
         # Protecting ourselves from awful Wcs solutions in input images
         if (not isinstance(e.message, lsst.pex.exceptions.DomainErrorException) and
                 not isinstance(e.message, lsst.pex.exceptions.RuntimeErrorException)):
             raise
         return False
 
-    imagePoly = convexHull([coord.getVector() for coord in imageCorners])
-    if imagePoly is None:
-        return False
+    imagePoly = lsst.sphgeom.ConvexPolygon.convexHull([coord.getVector() for coord in imageSkyCorners])
     return tractPoly.intersects(imagePoly)  # "intersects" also covers "contains" or "is contained by"
 
 

ups/meas_base.table

@@ -2,7 +2,7 @@ setupRequired(utils)
 setupRequired(afw)
 setupRequired(coadd_utils)
 setupRequired(daf_base)
-setupRequired(geom)
+setupRequired(sphgeom)
 setupRequired(numpy)
 setupRequired(pex_config)
 setupRequired(pipe_base)