The following projections are listed by "proj -lp" but don't have
entries in proj-parms.table:
geos : Geostationary Satellite View
lcca : Lambert Conformal Conic Alternative
sterea : Oblique Stereographic Alternative
vitk1 : Vitkovsky I
Can anyone provide the necessary parameter information, i.e. which
PROJ parameters they accept, and what (if any) default value should be
used?
FWIW, the "proj -lP" output for these says:
geos : Geostationary Satellite View
Azi, Sph&Ell
h=
lcca : Lambert Conformal Conic Alternative
Conic, Sph&Ell
lat_0=
sterea : Oblique Stereographic Alternative
Azimuthal, Sph&Ell
vitk1 : Vitkovsky I
Conic, Sph
lat_1= and lat_2=
BTW, it turns out that vitk1 was present in the old geo.h/geo_init.c,
but with no parameters. The other three weren't listed at all.
--
Glynn Clements <glynn@gclements.plus.com>
Glynn Clements wrote:
The following projections are listed by "proj -lp" but don't have
entries in proj-parms.table:
geos : Geostationary Satellite View
lcca : Lambert Conformal Conic Alternative
sterea : Oblique Stereographic Alternative
vitk1 : Vitkovsky I
Can anyone provide the necessary parameter information, i.e. which
PROJ parameters they accept, and what (if any) default value should be
used?
I know some about sterea. It accepts exactly the same parameters as
stere. It is an (a)lternative to Snyder's oblique stereographic
implemented as stere in PROJ. It should be used for some (all?)
European oblique stereographic based coordinate systems, including
Polish Uklad 1965 zones 1-4 (100% sure; still not a perfect match but
within sub-cm accuracy compared to about-meter accuracy of stere),
Denmark, Romania (both AFAIK only, not sure, Others please speak up).
stere is for American.
Maciek
Maciej Sieczka wrote:
> The following projections are listed by "proj -lp" but don't have
> entries in proj-parms.table:
>
> geos : Geostationary Satellite View
> lcca : Lambert Conformal Conic Alternative
> sterea : Oblique Stereographic Alternative
> vitk1 : Vitkovsky I
>
> Can anyone provide the necessary parameter information, i.e. which
> PROJ parameters they accept, and what (if any) default value should be
> used?
I know some about sterea. It accepts exactly the same parameters as
stere.
Looking at the PROJ source code, sterea doesn't accept any additional
parameters, whereas stere accepts lat_ts=.
stere is defined as:
STERE:Stereographic:KFACT=ask,1.0;LAT0=ask,0.0;LATTS=ask,0.0;LON0=ask,20.0
For sterea, I'd assume that the KFACT=1 and LAT0=0 defaults are
probably reasonable.
I'm not sure where the LON0 default comes from; of 121 projections,
119 accept LON0 (UPS and UTM are the exceptions), and 100 of those
have 20 as the default.
So, I'll add this for sterea:
STEREA:Oblique Stereographic Alternative:KFACT=ask,1.0;LAT0=ask,0.0;LON0=ask,20.0
--
Glynn Clements <glynn@gclements.plus.com>
Glynn Clements wrote:
Maciej Sieczka wrote:
The following projections are listed by "proj -lp" but don't have
entries in proj-parms.table:
geos : Geostationary Satellite View
lcca : Lambert Conformal Conic Alternative
sterea : Oblique Stereographic Alternative
vitk1 : Vitkovsky I
Can anyone provide the necessary parameter information, i.e. which
PROJ parameters they accept, and what (if any) default value should be
used?
geos projection needs only longitude and height (but doesn't say no to kfact). Latitude seems to be fixed at 0 degrees. In reality most geostationary satellites seem to deviate a little from 0 degrees. Pity, because then geos can't be used (but nsper projection can). Height is usually about 35700-35800 km.
http://www.n2yo.com
GEOS:HEIGH=ask,35800000.0;LON0=ask,20.0
I'm not sure where the LON0 default comes from; of 121 projections,
119 accept LON0 (UPS and UTM are the exceptions), and 100 of those
have 20 as the default.
I can explain that. I had a test map centered around lon 20, lat 55 when I added the projections back in 1998. I used 20/55 as default for most. May not please everyone to have Europe as default but was better than making up something for which I did not have a map and could not test. And using "neutral" 0/0 was not valid for many projections so I chose to use a real world example as default.
Morten
Morten Hulden wrote:
>>> The following projections are listed by "proj -lp" but don't have
>>> entries in proj-parms.table:
>>>
>>> geos : Geostationary Satellite View
>>> lcca : Lambert Conformal Conic Alternative
>>> sterea : Oblique Stereographic Alternative
>>> vitk1 : Vitkovsky I
>>>
>>> Can anyone provide the necessary parameter information, i.e. which
>>> PROJ parameters they accept, and what (if any) default value should be
>>> used?
geos projection needs only longitude and height (but doesn't say no to
kfact). Latitude seems to be fixed at 0 degrees. In reality most
geostationary satellites seem to deviate a little from 0 degrees. Pity,
because then geos can't be used (but nsper projection can). Height is
usually about 35700-35800 km.
http://www.n2yo.com
GEOS:HEIGH=ask,35800000.0;LON0=ask,20.0
Thanks; added.
--
Glynn Clements <glynn@gclements.plus.com>