[Proj] Some need for updated proj-4 manuals
Gerald I. Evenden
geraldi.evenden at gmail.com
Mon Sep 15 11:24:52 EDT 2008
On Sunday 14 September 2008 11:34:06 pm Hamish wrote:
> Janne wrote:
> > Actually the minimium would be to have a list of available projections,
> $ proj -l
> > maybe some picture how it looks
> http://www.galleryofmapprojections.com/ ->
> http://www.csiss.org/map-projections/ (server down?)
I can't get the above to work.
The libproj4 manual has pictures of most of the projections.
> > and an accurate description of all parameters
> I wouldn't guarantee that it's a full set, but these are the ones used
> in the EPSG file.
I am sorry but I find the following meaningless beside very misleading.
> $ cat epsg | grep -v '^#' | tr ' ' '\n' | grep '^\+' | \
> cut -f1 -d'=' | sort | uniq
only applies to elliptical projections
What about +R and +R_V, +R_a, +R_g +R_h, +R_lat_a
use limited to 3 or 4 projections and possibly in different contexts
only one method besides +rf, +f, +e, +es
not a proj option
only for conics
only a few projections
only a couple of projections
not in libproj4--- nasty option and out of place
not in libproj4
only a few projections
not in libproj4 --- not projection parameter
only applies to UTM.
If you want a slightly more complete list of about 75 +options try:
a alpha azi b belgium beta czech e ellps es f gamma geoc
guam h k K k_0 lat_0 lat_1 lat_2 lat_b lat_t lat_ts lon_0
lon_1 lon_2 lonc lsat m M n no_cut no_off no_rot ns o_alpha
o_lat_1 o_lat_2 o_lat_c o_lat_p o_lon_1 o_lon_2 o_lon_c
o_lon_p o_proj over p path proj q R R_a R_A rf R_g R_h
R_lat_a R_lat_g rot R_V s south sym t theta tilt to_meter
units vopt W westo x_0 y_0 zone
> > and how they affect the result.
For a discussion of the above options see the libproj4 manual.
> A short sentence/paragraph on each of the above would be nice.
Only the setting of the earth's figure and a couple of the factors like x_0,
y_0 can be discussed at a generic level. Most operation need to be discussed
as part of the projection description---pretty much as now available.
> As Markus suggested, the (FW/OSGeo) proj4 wiki is a nice place to work
> on collaborative documents.
The above is really a web for cs2cs and and only has a smattering of proj
related material. Also, I am not sure whether the internals are up to
> I made a start at naming the above, if others could please complete...
The list I made is fairly complete as I grepped it out of the RCS directory.
> There you will find nice things like:
> == Documentation ==
> * General Parameter Notes
> * Projections List page on the GeoTIFF site includes information on how
> to describe many common projections with PROJ.4 command arguments.
> > The idea behind using libraries is that such work that can
> > be done only once... also would be done only once.
What about updates and upgrades? That often affect manual contents.
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> Proj at lists.maptools.org
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