Changes between Version 2 and Version 3 of Processing/demcompare

Timestamp:

Sep 2, 2014, 12:08:41 PM (10 years ago)

Author:

stgo

Comment:

--

Processing/demcompare

@@ -11 +11 @@
 Unless you have an SSD available in your machine this will probably take a while.
 
-This will create a patched aster dem to compare to the lidar dem, this will not be smoothed and as such is the raw ASTER data. It will give 2 outputs on completion the first is only the area covered by the lidar files, the second is the area only covered by the lidar data. All outputs are in metres.
+This will create a patched aster dem to compare to the lidar dem, this will not be smoothed and as such is the raw ASTER data. It will give 2 outputs on completion the first is only the area covered by the lidar files, the second is the entire dem. All outputs are in metres.
 
-Preferably the averages would be around 0 metres, but in practice it tends to be around 4 - 8 metres for UK data and varying for UTM data.
+{{{
+Temp folder created at:/tmp/grassdb-24688-115643
+Calculation performed:GB13_10_2014_156_lidar_ASTER_bng.dem-ASTER_tiles.dem
+The maps were compared in:WGS84LL
+GB13_10_2014_156_lidar_ASTER_bng.dem was imported in:UKBNG
+ASTER_tiles.dem sum     :1420384.824150
+
+GB13_10_2014_156_lidar_ASTER_bng.dem sum        :1444242.484528
+
+Comparison sum  :-23857.657357
+
+Difference statistics:
+Min:            -69.939673828125
+Max:            32.3908696899414
+Sum:            -23857.6575275853
+Mean:           -1.8243983732955
+Median:         -0.985404
+Absolute mean:  5.99935342521819
+Std deviation:  8.54745020068044
+Total cells:    39672
+Non-null cells: 13077
+
+
+Unmasked statistics:
+Min:            -69.939673828125
+Max:            32.3908696899414
+Sum:            -24706.5998933041
+Mean:           -0.641529909984007
+Median:         5.49316e-07
+Absolute mean:  2.21956360209108
+Std deviation:  5.18281446074588
+Total cells:    39672
+Non-null cells: 38512
+}}}
+
+Preferably the mean (non-absolute) for the lidar area would be around 0 metres, but in practice it tends to be around 2 to 4 metres for UK data and varying for UTM data.
 
 You can compare 2 dems already created using
@@ -23 +58 @@
 Which will skip the patching process and just give the dem outputs, if you use identical dems the outputs will be 0.
 
+
+=== Non standard outputs ===
 There are a few other options for deeper analysis of dems, and analysis of trends over years
+
+{{{
+--output OUTPUT       output the resultant comparison DEM for inspection in
+                        another program.
+}}}
+
+Use this to inspect the created dem and comparison dem in envi, you can confirm figures from these.
+
+{{{
+--histogram HISTOGRAM
+                        Create a histogram and output it as a png at specified
+                        location. Include file extension.
+--png PNG               Create a PNG of the difference dem at the specified
+                        location. Include file extension.
+}}}
+
+The histogram option provides a better visualisation of the mean data. PNG can be used to provide quick looks at a heatmap of the data for comparison.
+
+
+=== Batch processing ===
+{{{
+  --csv                 Output as csv format for batch processing.
+  --script              Use with csv to indicate return rather than print
+}}}
+
+Use these two for batch processing, can be useful for creating profiles of whole years worth of data. These would be helpful if we wanted to see our overall accuracy over the year.