[Liblas-commits] laszip: tweak language and layout a little bit

Fri Feb 4 23:19:30 EST 2011

details:   http://hg.liblas.orglaszip/rev/cf8e2b3d53ec
changeset: 181:cf8e2b3d53ec
user:      Howard Butler <hobu.inc at gmail.com>
date:      Fri Feb 04 22:19:23 2011 -0600
description:
tweak language and layout a little bit

diffstat:

 docs/source/index.rst |  89 ++++++++++++++++++++++++++++++--------------------
 1 files changed, 54 insertions(+), 35 deletions(-)

diffs (127 lines):

diff -r 54cb2defd33c -r cf8e2b3d53ec docs/source/index.rst

--- a/docs/source/index.rst	Fri Feb 04 19:19:52 2011 -0800
+++ b/docs/source/index.rst	Fri Feb 04 22:19:23 2011 -0600
@@ -4,9 +4,13 @@
 LASzip
 ******************************************************************************
 
+Download
+------------------------------------------------------------------------------
 
-Current Release(s)
-------------------------------------------------------------------------------
+
+
+Source
+..............................................................................
 
 * **2011-02-01** 
 
@@ -16,13 +20,19 @@
   - `laszip-1.0.1-src.zip <http://download.osgeo.org/laszip/laszip-1.0.0.zip>`_ 
     `(md5) <http://download.osgeo.org/liblas/laszip-1.0.1.zip.md5>`__
 
-  - See `OSGeo4W <http://trac.osgeo.org/osgeo4w>`__ for Windows release.
+Binaries
+..............................................................................
 
-  - Or try `laszip.exe`_ a very efficient standalone implementation based
-    on the lighter-weight `LASlib`_ API used by `LAStools`_
+  - See `OSGeo4W`_ for Windows .lib and 
+    include files to compile LASzip into your own application. `libLAS`_ 
+    binaries through `OSGeo4W`_ also link LASzip.
+
+  - A simple Windows binary, `laszip.exe`_, is also available for 
+    explicit compression and decompression tasks to and from `ASPRS LAS format`_.
+    
 
 Development Source
-..............................................................................
+------------------------------------------------------------------------------
 
 * Current Trunk: http://hg.liblas.org/zip
 
@@ -30,39 +40,46 @@
 Background
 ------------------------------------------------------------------------------
 
-LASzip is a compression library that was developed by `Martin Isenburg`_ for 
-compressing `ASPRS LAS format`_ data in his `LAStools`_.  
-It has been provided as an `LGPL`_-licensed stand-alone software library to allow 
-other softwares that handle LAS data to read and write LASzip-compressed data.  
-libLAS can optionally take advantage of LASzip as of libLAS 1.6.0b4 to read 
-and write compressed data. Currently, both LAStools and libLAS can interchange
-data using LASzip compression.
+LASzip is a compression library that was developed by `Martin Isenburg`_ for
+compressing `ASPRS LAS format`_ data in his `LAStools`_. It has been provided
+as an `LGPL`_-licensed stand-alone software library to allow other softwares
+that handle LAS data to read and write LASzip-compressed data. The
+BSD-licensed `libLAS`_ and the LGPL-licensed `LASlib`_ can take
+advantage of LASzip to read and write compressed data.
 
-The compression can be many times smaller and many times faster than `bz2`_,
-`gzip`_, and `rar`_ because it takes advantage of knowing what the different
-bytes in a LAS file represent. For example, the x and y coordinate of a
-point are predicted by adding their delta in the preceding two points to 
-the x and y of the last point, whereas the gps_time difference between
-subsequent points is expressed as a multiple of the most common increment,
-while RGB valued are compressed with simple difference coding. In each case
-the prediction residuals are compressed with adaptive arithemetic coding.
+LASzip compression can be many times smaller and many times faster than
+`bz2`_, `gzip`_, and `rar`_ because it takes advantage of knowing what the
+different bytes in a LAS file represent. For example, the ``x`` and ``y``
+coordinate of a point are predicted by adding their delta in the preceding two
+points to the ``x`` and ``y`` of the last point, whereas the difference
+between subsequent points' time values is expressed as a multiple of the most
+common increment, while RGB valued are compressed with simple difference
+coding. In each case the prediction residuals are compressed with adaptive
+arithmetic coding.
 
-The compressor treats the LAS points of types 0, 1, 2, 3, 4, 5, and 6  as 
-onsisting of a number of items: POINT10, GPSTIME11, RGB12, and WAVEPACKET13
-and uses separate modules with separate version numbers to compress each
-item. This makes it easy to improve, for example, the compressor for the
-gps_time without affecting the other compression schemes, while at the same
-time guaranteeing full backwards compatability. More importantly it allows
-to add new LAS point types as the LAS specification evolves into the future.
+The compressor treats the LAS points of types 0, 1, 2, 3, 4, 5, and 6 as
+consisting of a number of items: POINT10, GPSTIME11, RGB12, and WAVEPACKET13
+and uses separate modules with separate version numbers to compress each item.
+This makes it easy to improve, for example, the compressor for the
+``gps_time`` without affecting the other compression schemes while
+guaranteeing full backwards compatibility. More importantly it allows the
+engine to add new LAS point types as the LAS specification evolves into the
+future without affecting existing point types.
 
-Another advantage of LASzip over generic compressors is that it allows you
-to treat the compressed LAZ files just like standard LAS files and load them
-directly from compressed form into your application without the need to ever
-uncompress them points. The availability of reading and writing compressed
-LAZ files via the two APIs `libLAS`_ and `lasLIB`_ makes it easy to add 
-native LAZ support to your own software package.
+Another advantage of LASzip over generic compressors is that it allows you to
+treat the compressed LAZ files just like standard LAS files and load them
+directly from compressed form into your application without the need to
+decompress and write out the data in an uncompressed form. The availability of
+the two APIs `libLAS`_ and `lasLIB`_ with LASzip capability makes it easy to
+add native LAZ support to your own software package.
 
+.. note::
+    `libLAS`_ externally links to released forms of the library at 
+    http://laszip.org while `LASlib`_ currently embeds this same 
+    compression/decompression codebase.
 
+
+.. _`OSGeo4W`: http://trac.osgeo.org/osgeo4w
 .. _`Martin Isenburg`: http://www.cs.unc.edu/~isenburg
 .. _`ASPRS LAS format`: http://www.asprs.org/society/committees/standards/lidar_exchange_format.html
 .. _`LGPL`: http://en.wikipedia.org/wiki/GNU_Lesser_General_Public_License
@@ -71,5 +88,6 @@
 .. _`rar`: http://en.wikipedia.org/wiki/Rar
 .. _`LAStools`: http://lastools.org
 .. _`libLAS`: http://liblas.org
-.. _`lasLIB`: http://www.cs.unc.edu/~isenburg/lastools/download/laslib.zip
-.. _`laszip.exe`: http://www.cs.unc.edu/~isenburg/lastools/download/laszip.exe
+.. _`lasLIB`: http://www.cs.unc.edu/~isenburg/lastools/download/laslib_README.txt
+.. _`lasLIB source`: http://www.cs.unc.edu/~isenburg/lastools/download/laslib.zip
+.. _`laszip.exe`: http://www.cs.unc.edu/~isenburg/lastools/
