Changes between Version 10 and Version 11 of Procedures/PhotoScan

Timestamp:

Nov 8, 2018, 2:27:47 PM (5 years ago)

Author:

wja

Comment:

--

Procedures/PhotoScan

@@ -35 +35 @@
 }}}
 
-* If no GCPs have been input in config file,  (gcp_csv_path = None) '''or if gcp_csv_path does not exist''', then ps_ortho_processing_before_input_gcp.py will run through the whole PhotoScan workflow without GCPs.
+* If no GCPs have been input in config file,  (gcp_csv_path = None) or if gcp_csv_path does not exist, then ps_ortho_processing_before_input_gcp.py will run through the whole PhotoScan workflow without GCPs.
 * If a path to GCP CSV has been input into the config file, these GCP coordinates will need to be manually positioned to their correct locations on the aligned photographs. Once this has been achieved, the second script can be run:
 
@@ -45 +45 @@
 The same config template is used.[[BR]]
 The project directory (defined in config file) is the location of the PhotoScan project file (*.psx) and other data produced whilst processing.[[BR]]
-The output directory (also defined in config) is where the Point Cloud, DEM and/or Orthomosaic is exported, if the associated parameters are True in config file. If the output directory does not exist, then it will be created.
+The output directory (also defined in config) is where the Point Cloud, DEM and/or Orthomosaic is exported, if the associated parameters are True in config file. If the output directory does not exist, then it will be created.[[BR]]
+[[BR]]
+'''Quality Checks'''[[BR]]
+To assess the quality of the exported data, compare the orthomosaic to Fenix/Owl data, or any higher spatial resolution imagery that you have access to. Use this to assess if the X and Y accuracy is suitable.[[BR]]
+For the Z (vertical) accuracy, you should compare the generated DEM to any points of known elevation at the time of flight but not the GCPs used in processing. For UK projects, there is good coverage of LiDAR data which may be able to make a good comparison. You can calculate the bias and RMSE between the processed elevations and the expected elevations (inferred from proxy data). Any statistical metrics calculated should be reported in the delivery's Read_Me.[[BR]]
+If the accuracy of the data is questionable, investigate whether this is caused by the following:
+ * GCPs
+  * GCPs need to be frequent, well spread, precise and in the correct units. Also consider reprojection errors if the GCPs and/or exported data are in contrasting projections.
+ * Eventfile
+  * Check the values in the eventfile. There may have been a problem when extracted them from the navigation data.
+ * Processing
+  * Check that the GCP placement in PhotoScan has been undertaken in as many photographs that GCPs are present in as possible. Also look at the residual error of the projects spatial fit. Unusually high error values for a particular GCP marker would suggest that it has been placed in the wrong location.
 
 == Creating Delivery ==