Merge branch 'tickets/DM-45709'

lsst · Aug 21, 2024 · 76fe02a · 76fe02a
2 parents 5c9cb89 + d78f4a7
commit 76fe02a
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Showing 2 changed files with 17 additions and 7 deletions.
diff --git a/python/lsst/ip/diffim/computeSpatiallySampledMetrics.py b/python/lsst/ip/diffim/computeSpatiallySampledMetrics.py
@@ -276,7 +276,7 @@ def _evaluateLocalMetric(self, src, science, matchedTemplate, template, differen
         bbox.grow(metricRegionSize)
         bbox = bbox.clippedTo(science.getBBox())
         nPix = bbox.getArea()
-        pixScale = science.wcs.getPixelScale()
+        pixScale = science.wcs.getPixelScale(bbox.getCenter())
         area = nPix*pixScale.asDegrees()**2
         peak = src.getFootprint().getPeaks()[0]
         src.set('x', peak['i_x'])

diff --git a/python/lsst/ip/diffim/dcrModel.py b/python/lsst/ip/diffim/dcrModel.py
@@ -288,7 +288,7 @@ def wcs(self):
 
         Returns
         -------
-        bbox : `lsst.afw.geom.SkyWcs`
+        wcs : `lsst.afw.geom.SkyWcs`
             Coordinate system definition (wcs) for the exposure.
         """
         return self._wcs
@@ -403,7 +403,7 @@ def buildMatchedTemplate(self, exposure=None, order=3,
         if bbox is None:
             bbox = self.bbox
         dcrShift = calculateDcr(visitInfo, self.wcs, self.effectiveWavelength, self.bandwidth, len(self),
-                                splitSubfilters=splitSubfilters)
+                                splitSubfilters=splitSubfilters, bbox=bbox)
         templateImage = afwImage.ImageF(bbox)
         refModel = None
         for subfilter, dcr in enumerate(dcrShift):
@@ -729,7 +729,8 @@ def applyDcr(image, dcr, useInverse=False, splitSubfilters=False, splitThreshold
     return shiftedImage
 
 
-def calculateDcr(visitInfo, wcs, effectiveWavelength, bandwidth, dcrNumSubfilters, splitSubfilters=False):
+def calculateDcr(visitInfo, wcs, effectiveWavelength, bandwidth, dcrNumSubfilters, splitSubfilters=False,
+                 bbox=None):
     """Calculate the shift in pixels of an exposure due to DCR.
 
     Parameters
@@ -747,6 +748,10 @@ def calculateDcr(visitInfo, wcs, effectiveWavelength, bandwidth, dcrNumSubfilter
     splitSubfilters : `bool`, optional
         Calculate DCR for two evenly-spaced wavelengths in each subfilter,
         instead of at the midpoint. Default: False
+    bbox : `lsst.afw.geom.Box2I`, optional
+        Bounding box for the region of interest for evaluating the local
+        pixelScale (defaults to the Sky Origin of the ``wcs`` provided if
+        ``bbox`` is None).
 
     Returns
     -------
@@ -768,17 +773,22 @@ def calculateDcr(visitInfo, wcs, effectiveWavelength, bandwidth, dcrNumSubfilter
                                                  elevation=visitInfo.getBoresightAzAlt().getLatitude(),
                                                  observatory=visitInfo.getObservatory(),
                                                  weather=visitInfo.getWeather())
+        if bbox is not None:
+            pixelScale = wcs.getPixelScale(bbox.getCenter()).asArcseconds()
+        else:
+            pixelScale = wcs.getPixelScale().asArcseconds()
+
         if splitSubfilters:
-            diffRefractPix0 = diffRefractAmp0.asArcseconds()/wcs.getPixelScale().asArcseconds()
-            diffRefractPix1 = diffRefractAmp1.asArcseconds()/wcs.getPixelScale().asArcseconds()
+            diffRefractPix0 = diffRefractAmp0.asArcseconds()/pixelScale
+            diffRefractPix1 = diffRefractAmp1.asArcseconds()/pixelScale
             diffRefractArr = [diffRefractPix0*weight[0] + diffRefractPix1*weight[1],
                               diffRefractPix0*weight[1] + diffRefractPix1*weight[0]]
             shiftX = [diffRefractPix*np.sin(rotation.asRadians()) for diffRefractPix in diffRefractArr]
             shiftY = [diffRefractPix*np.cos(rotation.asRadians()) for diffRefractPix in diffRefractArr]
             dcrShift.append(((shiftY[0], shiftX[0]), (shiftY[1], shiftX[1])))
         else:
             diffRefractAmp = (diffRefractAmp0 + diffRefractAmp1)/2.
-            diffRefractPix = diffRefractAmp.asArcseconds()/wcs.getPixelScale().asArcseconds()
+            diffRefractPix = diffRefractAmp.asArcseconds()/pixelScale
             shiftX = diffRefractPix*np.sin(rotation.asRadians())
             shiftY = diffRefractPix*np.cos(rotation.asRadians())
             dcrShift.append((shiftY, shiftX))