[GRASS5] geo.h and geo_init.c

[Eric G. Miller]

I'm trying to clean up geo.h and geo_init.c and disentangle them from
g.setproj.  At the moment, I'm converting the tables UNITS and DESC
into const structs and I'm scratching my head over a couple of things.

Some of the projection parameters defines have the same value as
others.  Why?

LONLOW == OLATP
LON0   == LATHIGH
FLOLOW == THETA
AZIM   == LONHIGH
INTLOW == Y0
ZONE   == FLOHIGH
BOOLOW == SPATH
GUAM   == INTHIGH

Then, when I get to the DESC table, there are several holes (that is,
no description):

DESC[2]  ==  DESC[OLAT1]
DESC[4]  ==  DESC[OLAT2]
DESC[11] ==  DESC[OLON1]
DESC[13] ==  DESC[OLON2]
DESC[19] ==  DESC[OALPHA]
DESC[35] ==  DESC[INTHIGH]
DESC[38] ==  DESC[NODEFS]

Are the #defines beginning with "O" supposed to mean "old" and therefore
unused?  That doesn't seem 100% the case since OLONP and OLATP have
descriptions "Latitude/Longitude of New Pole [o_lat/lon_p]".

It'd be useful to have descriptions for what all of the #define factors
are used for (some are obvious, but others aren't).

I've added USfoot (USfeet), USinch (USinches), USyard (USyards), and
USmile (USmiles) to the UNITS table.  I've noticed there are a few
places where code defines a different idea of unit conversion tables.
Those should be changed so we just have one table of linear conversions
to meters...

I intend to move all the globals in geo.h either to geo_init.c for
the tables, or to g.setproj for the others.  Can anybody think
why I shouldn't remove the following from geo.h?

int ier, proj_index, zone, snum, spath;
double radius, kfact, mfact, msfact, nfact, qfact, wfact, unit_fact,
       x_false, y_false, heigh, azim, tilt;

struct used_opt USED_in[NOPTIONS];
struct used_opt USED_out[NOPTIONS];

double LLSTUFF[NLLSTUFF];

double prompt_num_double(); ???

The remaining globals in "geo.h" will be extern'ed, const qualified
and defined in "geo_init.c".

extern const struct conv_fact UNITS[NUNITS];
extern const struct opt_req   TABLE[NPROJES][NOPTIONS];
extern const char             DESC[NOPTIONS][63];

-- 
Eric G. Miller <egm2 at jps.net>