Test GSHHS tools with GSHHS 1.10 database

[jjr8]

GSHHS maintains a complicated numbering scheme, in which the GSHHS software and GSHHS database format have different version numbers. The GSHHS database itself also has a version number, which seems to be identical to the software. In any case, the latest database version number seems to 1.10, but my reading of the GSHHS readme (below) is that the database format is still 1.4. If true, this means the existing MGET tools should work fine with the 1.10 database.

Version 1.10 May 1, 2008
Due to a numbering snafu the GMT 4.2.1 release started calling
the GSHHS data set using the same numbering as the GSHHS software.
Thus, GSHHS v 1.9 is the data set verson that follows v1.6.
For the GMT 4.3.0 release the GSHHS version is 1.10 since we
have added two missing islands off Long Island, NY.
Also, thanx to Markus Metz the gshhstograss.c has been updated.
--------------------------------------------------------------
Version 1.9 Sept 1, 2007

Now distributing the WDB borders and rivers with GSHHS, hence
gshhs.c needed a few tweaks to recognize the difference.  No
data format change, but we increment version number to 1.6 do
indicate a change in composition (river+borders added).
--------------------------------------------------------------
Version 1.8 March 31, 2007

Minor fix to ensure gshhstograss.c will compile.  Version 1.5
of the GSHHS data released, fixing a few crossings and dupli-
cate points.  No data format change so 1.7 can read as well.

--------------------------------------------------------------
Version 1.7 Nov 11, 2006

Minor bug fix: gshhs.c used && instead of & in one of the bit
manipulations, thus always yielding 1 as the level.

--------------------------------------------------------------
Version 1.6 May 13, 2006

Minor update to handle the latest GSHHS v1.4 database. Once again
we claim that now, for sure, GSHHS is finally self-consistent!
Due to a bug in our consistency checker a few lingering problems
made it into v1.3 - these should now all be gone.  Many thanx to
Thomas DeMay for contributing the results from his error checking.
We have also once again made changes to the GSHHS header structure
to make it only contain integer*4 (and not a mix of 2- and 4-byte
integers) as well as be a multiple of 16 bytes.  Thus, the new
structure is

int id;				/* Unique polygon id number, starting at 0 */
int n;				/* Number of points in this polygon */
int flag;			/* level + version << 8 + greenwich << 16 + source << 24 
int west, east, south, north;	/* min/max extent in micro-degrees */
int area;			/* Area of polygon in 1/10 km^2 */


Here, level, version, greenwhich, and source are
level:		1 land, 2 lake, 3 island_in_lake, 4 pond_in_island_in_lake
version:	Set to 4 for GSHHS version 1.4
greenwich:	1 if Greenwich is crossed
source:		0 = CIA WDBII, 1 = WVS

These values are recovered using bit math.  For further info about
GSHHS see the earlier comments below.

<Remainder of readme file omitted>

[jjr8]

I tested this with ArcGIS 9.2 SP5 and MGET 0.5b1. All files worked, although the gshhs_f.b file reported the warning "Output feature 0 cannot be dissolved into other inputs because of memory limitations". The only negative consequence of this is that Asia/Africa is not a single polygon. Instead, the fraction of Africa west of the Prime Meridian is a separate polygon.

I did update the documentation for the tool, to indicate that it was tested with GSHHS 1.10. This change was implemented in [240], which will be released as MGET 0.5b2.