Index: trunk/stac/src/stacSize.c
===================================================================
--- trunk/stac/src/stacSize.c	(revision 3669)
+++ trunk/stac/src/stacSize.c	(revision 3683)
@@ -94,17 +94,17 @@
     // Tweak the maps to account for the offset
     if (xMapDiff != NULL) {
-	*xMapDiff = floor(xMin);
+	*xMapDiff = floorf(xMin);
     }
     if (yMapDiff != NULL) {
-	*yMapDiff = floor(yMin);
+	*yMapDiff = floorf(yMin);
     }
     for (int i = 0; i < nImages; i++) {
 	psPlaneTransform *map = maps->data[i]; // The map of interest
-	map->x->coeff[0][0] -= floor(xMin);
-	map->y->coeff[0][0] -= floor(yMin);
+	map->x->coeff[0][0] -= floorf(xMin);
+	map->y->coeff[0][0] -= floorf(yMin);
     }
 
-    *outnx = (int)(xMax + 0.5) - (int)xMin;
-    *outny = (int)(yMax + 0.5) - (int)yMin;
+    *outnx = (int)ceilf(xMax - xMin);
+    *outny = (int)ceilf(yMax - yMin);
 
     psTrace("stac.size", 1, "Output size is to be %dx%d\n", *outnx, *outny);