Remove redundant CRS descriptions from LAS 1.5

source/02.00_definition.txt

@@ -43,11 +43,10 @@ header contained within the Public Header Block ("Start of Waveform Data Packet
 Record").
 
 .. include:: ./02.01_legacy.sub
-.. include:: ./02.02_crs.sub
-.. include:: ./02.03_datatypes.sub
-.. include:: ./02.04_header.sub
-.. include:: ./02.05_vlr.sub
-.. include:: ./02.06_point.sub
-.. include:: ./02.07_evlr.sub
+.. include:: ./02.02_datatypes.sub
+.. include:: ./02.03_header.sub
+.. include:: ./02.04_vlr.sub
+.. include:: ./02.05_point.sub
+.. include:: ./02.06_evlr.sub
 
 

source/02.03_datatypes.sub → source/02.02_datatypes.sub

@@ -1,3 +1,7 @@
+.. raw:: latex
+
+    \newpage
+
 Data Types
 ................................................................................
 

source/02.04_header.sub → source/02.03_header.sub

@@ -1,3 +1,7 @@
+.. raw:: latex
+
+    \newpage
+
 .. _headerblock_label:
 
 Public Header Block
@@ -179,10 +183,14 @@ defined as follows:
     |       |                       | for a system not directly supporting     |
     |       |                       | multiple returns.                        |
     +-------+-----------------------+------------------------------------------+
-    | 4     | WKT                   | If set, the Coordinate Reference System  |
-    |       |                       | (CRS) is WKT. This bit must be set in    |
-    |       |                       | LAS 1.5; GeoTIFF CRS definitions are no  |
-    |       |                       | longer supported in LAS 1.5.             |
+    | 4     | Well Known Text (WKT) | If set, the Coordinate Reference System  |
+    |       |                       | (CRS) is formatted as OGC WKT. This bit  |
+    |       |                       | must be set in LAS 1.5; GeoTIFF CRS      |
+    |       |                       | definitions from prior versions of LAS   |
+    |       |                       | are no longer supported in LAS 1.5.      |
+    |       |                       | The CRS definition will be located in    |
+    |       |                       | the WKT VLR(s) or EVLR(s) as defined in  |
+    |       |                       | the :ref:`crs_label` section.            |
     +-------+-----------------------+------------------------------------------+
     | 5     | Reserved              | Must be set to zero.                     |
     +-------+-----------------------+------------------------------------------+

source/03_crs.txt

@@ -2,18 +2,24 @@
 
     \newpage
 
+.. _crs_label:
+
 Coordinate Reference System
 --------------------------------------------------------------------------------
 
-Coordinate Reference System (CRS) information is required for a LAS 1.5 file.
-LAS 1.5 defines VLRs in :ref:`vlrdef_label` and EVLRs in :ref:`evlrdef_label` and
-requires them for specifying the Coordinate Reference System (CRS) of the file.
-
-CRS information shall be placed in VLRs or EVLRs and represented as `OGC Well
-Known Text <https://www.ogc.org/standard/wkt-crs/>`__ (WKT) without regard to
+Coordinate Reference System (CRS) information is required for a LAS 1.5 file
+and must be placed in :ref:`vlrdef_label` or :ref:`evlrdef_label`.
+LAS 1.5 CRS information shall be represented as `OGC Well
+Known Text <https://www.ogc.org/standard/wkt-crs/>`__ (WKT), as indicated by
 the :ref:`Global Encoding <globalencoding_link>` bit.
 
-GeoTIFF CRS representations are no longer supported as of LAS 1.5.
+GeoTIFF CRS representations from prior versions of LAS are not supported in LAS 1.5.
+
+It is considered a file error to have more than one WKT VLR or EVLR in the file.
+A writer can efficiently revise a CRS definition without rewriting the entire LAS file by
+"superseding" the existing CRS VLR or EVLR and appending a new CRS definition in an EVLR. 
+Superseding is performed by changing the
+Record ID of the VLR or EVLR to match the :ref:`superseded_vlr_label` VLR definition.
 
 .. _crs_wkt:
 
@@ -70,8 +76,8 @@ supplemental parameterized math transform definition.
 | Record ID       | 2111                        |
 +-----------------+-----------------------------+
 
-This record must contain a Math Transform WKT consistent with the same WKT
-specification being used by :ref:`crs_wkt`, with the following considerations:
+This record must contain a Math Transform WKT Record consistent with the same WKT
+specification being used by the :ref:`Coordinate System WKT Record <crs_wkt>`, with the following considerations:
 
 * The OGC Math Transform WKT VLR data shall be a null-terminated string.
 * The OGC Math Transform WKT VLR data shall be considered UTF-8.

source/04_optional_vlrs.txt

@@ -35,7 +35,7 @@ Text Area Description
 | Record ID       | 3                           |
 +-----------------+-----------------------------+
 
-This VLR/EVLR is used for providing a textual description of the content of the
+This VLR is used for providing a textual description of the content of the
 LAS file. It is a null-terminated, free-form ASCII string.
 
 .. _extrabytes_vlr_label:
@@ -231,8 +231,8 @@ Superseded
 | Record ID       | 7                           |
 +-----------------+-----------------------------+
 
-This LASF Record ID is used to negate an existing VLR/EVLR when rewriting the
-file (to remove the undesired VLR/EVLR). It is used, for example, when
+This LASF Record ID is used to negate an existing VLR or EVLR when rewriting the
+file (to remove the undesired VLR or EVLR). It is used, for example, when
 updating a record such as projection information where a new EVLR is appended
 to the end of the LAS file. The existing VLR which has been superseded must be
 marked with the SUPERSEDED Record ID.