Index: trunk/psModules/src/camera/pmFPAExtent.c
===================================================================
--- trunk/psModules/src/camera/pmFPAExtent.c	(revision 19385)
+++ trunk/psModules/src/camera/pmFPAExtent.c	(revision 19388)
@@ -66,4 +66,14 @@
         cellExtent->y1 = PS_MAX(cellExtent->y1, roExtent->y1);
         psFree(roExtent);
+    }
+
+    // Don't have anything to base the true extent on, so have to give the hardwired value (largest possible extent)
+    if (readouts->n == 0) {
+	int xSize = psMetadataLookupS32(NULL, cell->concepts, "CELL.XSIZE");
+	int ySize = psMetadataLookupS32(NULL, cell->concepts, "CELL.YSIZE");
+	cellExtent->x0 = 0;
+	cellExtent->x1 = xSize;
+	cellExtent->y0 = 0;
+	cellExtent->y1 = ySize;
     }