Update parameters of cap_resolution().

Add parameter `gsd_scaling` instead of using `gsd_error_estimate` in an unintuitive way.

opendm/gsd.py

@@ -5,6 +5,7 @@ import math
 from repoze.lru import lru_cache
 from opendm import log
 
+
 def rounded_gsd(reconstruction_json, default_value=None, ndigits=0, ignore_gsd=False):
     """
     :param reconstruction_json path to OpenSfM's reconstruction.json
@@ -61,12 +62,15 @@ def image_scale_factor(target_resolution, reconstruction_json, gsd_error_estimat
         return 1
 
 
-def cap_resolution(resolution, reconstruction_json, gsd_error_estimate = 0.1, ignore_gsd=False, ignore_resolution=False, has_gcp=False):
+def cap_resolution(resolution, reconstruction_json, gsd_error_estimate = 0.1, gsd_scaling = 1.0, ignore_gsd=False,
+                   ignore_resolution=False, has_gcp=False):
     """
     :param resolution resolution in cm / pixel
     :param reconstruction_json path to OpenSfM's reconstruction.json
     :param gsd_error_estimate percentage of estimated error in the GSD calculation to set an upper bound on resolution.
+    :param gsd_scaling scaling of estimated GSD.
     :param ignore_gsd when set to True, forces the function to just return resolution.
+    :param ignore_resolution when set to True, forces the function to return a value based on GSD.
     :return The max value between resolution and the GSD computed from the reconstruction.
         If a GSD cannot be computed, or ignore_gsd is set to True, it just returns resolution. Units are in cm / pixel.
     """
@@ -76,14 +80,16 @@ def cap_resolution(resolution, reconstruction_json, gsd_error_estimate = 0.1, ig
     gsd = opensfm_reconstruction_average_gsd(reconstruction_json, use_all_shots=has_gcp or ignore_resolution)
 
     if gsd is not None:
-        gsd = gsd * (1 - gsd_error_estimate)
+        gsd = gsd * (1 - gsd_error_estimate) * gsd_scaling
         if gsd > resolution or ignore_resolution:
-            log.ODM_WARNING('Maximum resolution set to GSD - {}% ({} cm / pixel, requested resolution was {} cm / pixel)'.format(gsd_error_estimate * 100, round(gsd, 2), round(resolution, 2)))
+            log.ODM_WARNING('Maximum resolution set to {} * (GSD - {}%) '
+                            '({:.2f} cm / pixel, requested resolution was {:.2f} cm / pixel)'
+                            .format(gsd_scaling, gsd_error_estimate * 100, gsd, resolution))
             return gsd
         else:
             return resolution
     else:
-        log.ODM_WARNING('Cannot calculate GSD, using requested resolution of {}'.format(round(resolution, 2)))
+        log.ODM_WARNING('Cannot calculate GSD, using requested resolution of {:.2f}'.format(resolution))
         return resolution
 
 
@@ -134,6 +140,7 @@ def opensfm_reconstruction_average_gsd(reconstruction_json, use_all_shots=False)
     
     return None
 
+
 def calculate_gsd(sensor_width, flight_height, focal_length, image_width):
     """
     :param sensor_width in millimeters
@@ -154,6 +161,7 @@ def calculate_gsd(sensor_width, flight_height, focal_length, image_width):
     else:
         return None
 
+
 def calculate_gsd_from_focal_ratio(focal_ratio, flight_height, image_width):
     """
     :param focal_ratio focal length (mm) / sensor_width (mm)

stages/odm_dem.py

@@ -13,6 +13,7 @@ from opendm import pseudogeo
 from opendm.tiles.tiler import generate_dem_tiles
 from opendm.cogeo import convert_to_cogeo
 
+
 class ODMDEMStage(types.ODM_Stage):
     def process(self, args, outputs):
         tree = outputs['tree']
@@ -28,11 +29,15 @@ class ODMDEMStage(types.ODM_Stage):
             ignore_resolution = True
             pseudo_georeference = True
 
+        # It is probably not reasonable to have accurate DEMs a the same resolution as the source photos, so reduce it
+        # by a factor!
+        gsd_scaling = 2.0
+
         resolution = gsd.cap_resolution(args.dem_resolution, tree.opensfm_reconstruction, 
-                        gsd_error_estimate=-1, 
-                        ignore_gsd=args.ignore_gsd,
-                        ignore_resolution=ignore_resolution,
-                        has_gcp=reconstruction.has_gcp())
+                                        gsd_scaling=gsd_scaling,
+                                        ignore_gsd=args.ignore_gsd,
+                                        ignore_resolution=ignore_resolution,
+                                        has_gcp=reconstruction.has_gcp())
 
         log.ODM_INFO('Classify: ' + str(args.pc_classify))
         log.ODM_INFO('Create DSM: ' + str(args.dsm))

stages/odm_orthophoto.py

@@ -13,6 +13,7 @@ from opendm.utils import double_quote
 from opendm import pseudogeo
 from opendm.multispectral import get_primary_band_name
 
+
 class ODMOrthoPhotoStage(types.ODM_Stage):
     def process(self, args, outputs):
         tree = outputs['tree']
@@ -23,18 +24,11 @@ class ODMOrthoPhotoStage(types.ODM_Stage):
         system.mkdir_p(tree.odm_orthophoto)
 
         if not io.file_exists(tree.odm_orthophoto_tif) or self.rerun():
-            gsd_error_estimate = 0.1
-            ignore_resolution = False
-            if not reconstruction.is_georeferenced():
-                # Match DEMs
-                gsd_error_estimate = -3
-                ignore_resolution = True
 
             resolution = 1.0 / (gsd.cap_resolution(args.orthophoto_resolution, tree.opensfm_reconstruction,
-                                                    gsd_error_estimate=gsd_error_estimate, 
-                                                    ignore_gsd=args.ignore_gsd,
-                                                    ignore_resolution=ignore_resolution,
-                                                    has_gcp=reconstruction.has_gcp()) / 100.0)
+                                                   ignore_gsd=args.ignore_gsd,
+                                                   ignore_resolution=not reconstruction.is_georeferenced(),
+                                                   has_gcp=reconstruction.has_gcp()) / 100.0)
 
             # odm_orthophoto definitions
             kwargs = {