Changes between Version 13 and Version 14 of OsgTerrainData

Timestamp:

Oct 27, 2011, 10:06:51 PM (13 years ago)

Author:

Torben Dannhauer

Comment:

--

OsgTerrainData

@@ -65 +65 @@
 
 To shift system load from HDD to CPU, compress all textures lossless with LZW. This will decrease rendering time a lot, because usually the HDD ist the bottleneck.
+
+This is an example bash script to process the images:
 {{{
-#!sh
-gdal_translate -co "COMPRESS=LZW" unsw ToDo
+mkdir /home/user/your/path/to/imagery/compressed
+
+cat compressFolder_LZW.sh 
+
+#!/bin/bash
+cd /home/user/your/path/to/imagery
+for file in `dir -d *` ; do
+echo "$file :"
+/usr/bin/gdal_translate -of GTiff -co "COMPRESS=LZW" $file compressed/$file
+done
 }}}
+
+==create overviews
+
+To reduce system load to resize the terrain textures on the fly multiple times, you should consider to create overviews embedded into your imagery.
+This allows VPB to use the existing overview of the fitting dimensions instead of creating it every time from scratch.
+Additionally you can improve the image quality, because VPB uses as OpenGL default the nearest neighbour interpolation, which results in bad texture quality.
+You can choose between several interpolation algorithms like average, gauss or cubic interpolation.
+
+Average interpolation has the advantage that is does not involve a 3x3 or 4x4 matrix, but only the adjacent pixels itself. So it does not lead to black edges on curved imagery edges with adjacent NODATA pixels.
+Gauss interpolation is only suitable on tiles without NOTDATA values, gut it smoothes the image which leads to better results in images with sharp edges or high frequency content.
+
+This is an example bash script to process the images:
+{{{
+cat createAddons.sh 
+
+#!/bin/bash
+cd /home/user/your/path/to/imagery
+for file in `dir -d *` ; do
+echo "$file :"
+/usr/bin/gdaladdo --config COMPRESS_OVERVIEW LZW -r average $file 2 4 8 16 32 64 128
+done
+}}}
+
 
 == Moon Data ==