matplotlib

If and when you have time on your hands, a projection that is rarely used but
quite interesting is Guyou's Doubly-Periodic Projection.  (See the first and
third figures in http://www.members.shaw.ca/quadibloc/maps/mcf0703.htm). 
This projection puts the worst distortion at four points in the ocean, and
does a reasonable job of preserving the shapes and relative sizes of the
major land masses.
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View this message in context: http://old.nabble.com/missing-projections-tp27297141p27297216.html
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Dr. Phillip M. Feldman wrote:
> Basemap offers many projections, but is missing two of the most useful ones:
>
> - For satellite applications, it would be helpful to have a "camera"
> projection, i.e., a projection that shows the Earth as viewed from a
> specified point in space.  This would be a generalization of the current
> geostationary projection.
>   

Philip:  Don't think the proj4 lib supports this.
> - Basemap current offers North-Polar and South-Polar azimuthal equidistant
> projections.  A useful generalization is the azimuthal equidistant
> projection with a specified latitude and longitude at the center of the map.
>   

That's already implemented - just use the 'aeqd' projection, specifying 
lat_0,lon_0,width and height keywords.

-Jeff

Jeff Whitaker wrote:
> Dr. Phillip M. Feldman wrote:
>   
>> Basemap offers many projections, but is missing two of the most useful ones:
>>
>> - For satellite applications, it would be helpful to have a "camera"
>> projection, i.e., a projection that shows the Earth as viewed from a
>> specified point in space.  This would be a generalization of the current
>> geostationary projection.
>>   
>>     
>
> Philip:  Don't think the proj4 lib supports this.
>   
I think it's already in there -- see nsper, for near sided perspective.

-Andrew

Andrew Straw wrote:
> Jeff Whitaker wrote:
>   
>> Dr. Phillip M. Feldman wrote:
>>   
>>     
>>> Basemap offers many projections, but is missing two of the most useful ones:
>>>
>>> - For satellite applications, it would be helpful to have a "camera"
>>> projection, i.e., a projection that shows the Earth as viewed from a
>>> specified point in space.  This would be a generalization of the current
>>> geostationary projection.
>>>   
>>>     
>>>       
>> Philip:  Don't think the proj4 lib supports this.
>>   
>>     
> I think it's already in there -- see nsper, for near sided perspective.
>
> -Andrew
>
>   
Hello Andrew-

It does sound as thought nsper is exactly what I need, but when I try to 
use it, I get the following error message:

ValueError: 'nsper' is an unsupported projection.
The supported projections are:

 aeqd             Azimuthal Equidistant
 poly             Polyconic
 gnom             Gnomonic
 moll             Mollweide
 tmerc            Transverse Mercator
 nplaea           North-Polar Lambert Azimuthal
 gall             Gall Stereographic Cylindrical
 mill             Miller Cylindrical
 merc             Mercator
 stere            Stereographic
 npstere          North-Polar Stereographic
 geos             Geostationary
 vandg            van der Grinten
 laea             Lambert Azimuthal Equal Area
 mbtfpq           McBryde-Thomas Flat-Polar Quartic
 sinu             Sinusoidal
 spstere          South-Polar Stereographic
 lcc              Lambert Conformal
 npaeqd           North-Polar Azimuthal Equidistant
 eqdc             Equidistant Conic
 cyl              Cylindrical Equidistant
 omerc            Oblique Mercator
 aea              Albers Equal Area
 spaeqd           South-Polar Azimuthal Equidistant
 ortho            Orthographic
 cass             Cassini-Soldner
 splaea           South-Polar Lambert Azimuthal
 robin            Robinson

Phillip

Phillip M. Feldman wrote:
> Andrew Straw wrote:
>> Jeff Whitaker wrote:
>>  
>>> Dr. Phillip M. Feldman wrote:
>>>      
>>>> Basemap offers many projections, but is missing two of the most 
>>>> useful ones:
>>>>
>>>> - For satellite applications, it would be helpful to have a "camera"
>>>> projection, i.e., a projection that shows the Earth as viewed from a
>>>> specified point in space.  This would be a generalization of the 
>>>> current
>>>> geostationary projection.
>>>>             
>>> Philip:  Don't think the proj4 lib supports this.
>>>       
>> I think it's already in there -- see nsper, for near sided perspective.
>>
>> -Andrew
>>
>>   
> Hello Andrew-
>
> It does sound as thought nsper is exactly what I need, but when I try 
> to use it, I get the following error message:
>
> ValueError: 'nsper' is an unsupported projection.
> The supported projections are:
>
> aeqd             Azimuthal Equidistant
> poly             Polyconic
> gnom             Gnomonic
> moll             Mollweide
> tmerc            Transverse Mercator
> nplaea           North-Polar Lambert Azimuthal
> gall             Gall Stereographic Cylindrical
> mill             Miller Cylindrical
> merc             Mercator
> stere            Stereographic
> npstere          North-Polar Stereographic
> geos             Geostationary
> vandg            van der Grinten
> laea             Lambert Azimuthal Equal Area
> mbtfpq           McBryde-Thomas Flat-Polar Quartic
> sinu             Sinusoidal
> spstere          South-Polar Stereographic
> lcc              Lambert Conformal
> npaeqd           North-Polar Azimuthal Equidistant
> eqdc             Equidistant Conic
> cyl              Cylindrical Equidistant
> omerc            Oblique Mercator
> aea              Albers Equal Area
> spaeqd           South-Polar Azimuthal Equidistant
> ortho            Orthographic
> cass             Cassini-Soldner
> splaea           South-Polar Lambert Azimuthal
> robin            Robinson
>
> Phillip     
Philip:  I think Andrew meant nsper is in proj4.  I'll look into adding 
support for it in Basemap.

-Jeff

Phillip M. Feldman wrote:
> Jeff Whitaker wrote:
>> Phillip M. Feldman wrote:
>>> Andrew Straw wrote:
>>>> Jeff Whitaker wrote:
>>>>  
>>>>> Dr. Phillip M. Feldman wrote:
>>>>>    
>>>>>> Basemap offers many projections, but is missing two of the most 
>>>>>> useful ones:
>>>>>>
>>>>>> - For satellite applications, it would be helpful to have a "camera"
>>>>>> projection, i.e., a projection that shows the Earth as viewed from a
>>>>>> specified point in space.  This would be a generalization of the 
>>>>>> current
>>>>>> geostationary projection.
>>>>>>             
>>>>> Philip:  Don't think the proj4 lib supports this.
>>>>>       
>>>> I think it's already in there -- see nsper, for near sided 
>>>> perspective.
>>>>
>>>> -Andrew
>>>>

Philip:  I've added the near-sided perspective projection to basemap svn 
- see the nsper_demo.py example.  It only works if the earth is assumed 
to be a perfect sphere (no ellipsoids allowed).

-Jeff
>>>>   
>>> Hello Andrew-
>>>
>>> It does sound as thought nsper is exactly what I need, but when I 
>>> try to use it, I get the following error message:
>>>
>>> ValueError: 'nsper' is an unsupported projection.
>>> The supported projections are:
>>>
>>> aeqd             Azimuthal Equidistant
>>> poly             Polyconic
>>> gnom             Gnomonic
>>> moll             Mollweide
>>> tmerc            Transverse Mercator
>>> nplaea           North-Polar Lambert Azimuthal
>>> gall             Gall Stereographic Cylindrical
>>> mill             Miller Cylindrical
>>> merc             Mercator
>>> stere            Stereographic
>>> npstere          North-Polar Stereographic
>>> geos             Geostationary
>>> vandg            van der Grinten
>>> laea             Lambert Azimuthal Equal Area
>>> mbtfpq           McBryde-Thomas Flat-Polar Quartic
>>> sinu             Sinusoidal
>>> spstere          South-Polar Stereographic
>>> lcc              Lambert Conformal
>>> npaeqd           North-Polar Azimuthal Equidistant
>>> eqdc             Equidistant Conic
>>> cyl              Cylindrical Equidistant
>>> omerc            Oblique Mercator
>>> aea              Albers Equal Area
>>> spaeqd           South-Polar Azimuthal Equidistant
>>> ortho            Orthographic
>>> cass             Cassini-Soldner
>>> splaea           South-Polar Lambert Azimuthal
>>> robin            Robinson
>>>
>>> Phillip     
>> Philip:  I think Andrew meant nsper is in proj4.  I'll look into 
>> adding support for it in Basemap.
>>
>> -Jeff
>>
> Thanks!


-- 
Jeffrey S. Whitaker         Phone  : (303)497-6313
Meteorologist               FAX    : (303)497-6449
NOAA/OAR/PSD  R/PSD1        Email  : Jeffrey.S.Whitaker@...
325 Broadway                Office : Skaggs Research Cntr 1D-113
Boulder, CO, USA 80303-3328 Web    : http://tinyurl.com/5telg

This sounds great.  Thanks!

So far I haven't figured out how to use it.  I downloaded the matplotlib 
SVN and installed it, but was not able to find "nsper_demo.py".

Phillip

Jeff Whitaker wrote:
> Phillip M. Feldman wrote:
>> Jeff Whitaker wrote:
>>> Phillip M. Feldman wrote:
>>>> Andrew Straw wrote:
>>>>> Jeff Whitaker wrote:
>>>>>  
>>>>>> Dr. Phillip M. Feldman wrote:
>>>>>>   
>>>>>>> Basemap offers many projections, but is missing two of the most 
>>>>>>> useful ones:
>>>>>>>
>>>>>>> - For satellite applications, it would be helpful to have a 
>>>>>>> "camera"
>>>>>>> projection, i.e., a projection that shows the Earth as viewed 
>>>>>>> from a
>>>>>>> specified point in space.  This would be a generalization of the 
>>>>>>> current
>>>>>>> geostationary projection.
>>>>>>>             
>>>>>> Philip:  Don't think the proj4 lib supports this.
>>>>>>       
>>>>> I think it's already in there -- see nsper, for near sided 
>>>>> perspective.
>>>>>
>>>>> -Andrew
>>>>>
>
> Philip:  I've added the near-sided perspective projection to basemap 
> svn - see the nsper_demo.py example.  It only works if the earth is 
> assumed to be a perfect sphere (no ellipsoids allowed).
>
> -Jeff
>>>>>   
>>>> Hello Andrew-
>>>>
>>>> It does sound as thought nsper is exactly what I need, but when I 
>>>> try to use it, I get the following error message:
>>>>
>>>> ValueError: 'nsper' is an unsupported projection.
>>>> The supported projections are:
>>>>
>>>> aeqd             Azimuthal Equidistant
>>>> poly             Polyconic
>>>> gnom             Gnomonic
>>>> moll             Mollweide
>>>> tmerc            Transverse Mercator
>>>> nplaea           North-Polar Lambert Azimuthal
>>>> gall             Gall Stereographic Cylindrical
>>>> mill             Miller Cylindrical
>>>> merc             Mercator
>>>> stere            Stereographic
>>>> npstere          North-Polar Stereographic
>>>> geos             Geostationary
>>>> vandg            van der Grinten
>>>> laea             Lambert Azimuthal Equal Area
>>>> mbtfpq           McBryde-Thomas Flat-Polar Quartic
>>>> sinu             Sinusoidal
>>>> spstere          South-Polar Stereographic
>>>> lcc              Lambert Conformal
>>>> npaeqd           North-Polar Azimuthal Equidistant
>>>> eqdc             Equidistant Conic
>>>> cyl              Cylindrical Equidistant
>>>> omerc            Oblique Mercator
>>>> aea              Albers Equal Area
>>>> spaeqd           South-Polar Azimuthal Equidistant
>>>> ortho            Orthographic
>>>> cass             Cassini-Soldner
>>>> splaea           South-Polar Lambert Azimuthal
>>>> robin            Robinson
>>>>
>>>> Phillip     
>>> Philip:  I think Andrew meant nsper is in proj4.  I'll look into 
>>> adding support for it in Basemap.
>>>
>>> -Jeff
>>>
>> Thanks!
>
>

Phillip M. Feldman wrote:
> This sounds great.  Thanks!
>
> So far I haven't figured out how to use it.  I downloaded the 
> matplotlib SVN and installed it, but was not able to find 
> "nsper_demo.py".
>
> Phillip

Phillip:  Basemap is a separate toolkit, you won't get it from the 
matplotlib svn trunk.  Instead of

svn co 
https://matplotlib.svn.sourceforge.net/svnroot/matplotlib/trunk/matplotlib 
matplotlib

do

svn co 
https://matplotlib.svn.sourceforge.net/svnroot/matplotlib/trunk/toolkits/basemap 
basemap

-Jeff

>
> Jeff Whitaker wrote:
>> Phillip M. Feldman wrote:
>>> Jeff Whitaker wrote:
>>>> Phillip M. Feldman wrote:
>>>>> Andrew Straw wrote:
>>>>>> Jeff Whitaker wrote:
>>>>>>  
>>>>>>> Dr. Phillip M. Feldman wrote:
>>>>>>>  
>>>>>>>> Basemap offers many projections, but is missing two of the most 
>>>>>>>> useful ones:
>>>>>>>>
>>>>>>>> - For satellite applications, it would be helpful to have a 
>>>>>>>> "camera"
>>>>>>>> projection, i.e., a projection that shows the Earth as viewed 
>>>>>>>> from a
>>>>>>>> specified point in space.  This would be a generalization of 
>>>>>>>> the current
>>>>>>>> geostationary projection.
>>>>>>>>             
>>>>>>> Philip:  Don't think the proj4 lib supports this.
>>>>>>>       
>>>>>> I think it's already in there -- see nsper, for near sided 
>>>>>> perspective.
>>>>>>
>>>>>> -Andrew
>>>>>>
>>
>> Philip:  I've added the near-sided perspective projection to basemap 
>> svn - see the nsper_demo.py example.  It only works if the earth is 
>> assumed to be a perfect sphere (no ellipsoids allowed).
>>
>> -Jeff
>>>>>>   
>>>>> Hello Andrew-
>>>>>
>>>>> It does sound as thought nsper is exactly what I need, but when I 
>>>>> try to use it, I get the following error message:
>>>>>
>>>>> ValueError: 'nsper' is an unsupported projection.
>>>>> The supported projections are:
>>>>>
>>>>> aeqd             Azimuthal Equidistant
>>>>> poly             Polyconic
>>>>> gnom             Gnomonic
>>>>> moll             Mollweide
>>>>> tmerc            Transverse Mercator
>>>>> nplaea           North-Polar Lambert Azimuthal
>>>>> gall             Gall Stereographic Cylindrical
>>>>> mill             Miller Cylindrical
>>>>> merc             Mercator
>>>>> stere            Stereographic
>>>>> npstere          North-Polar Stereographic
>>>>> geos             Geostationary
>>>>> vandg            van der Grinten
>>>>> laea             Lambert Azimuthal Equal Area
>>>>> mbtfpq           McBryde-Thomas Flat-Polar Quartic
>>>>> sinu             Sinusoidal
>>>>> spstere          South-Polar Stereographic
>>>>> lcc              Lambert Conformal
>>>>> npaeqd           North-Polar Azimuthal Equidistant
>>>>> eqdc             Equidistant Conic
>>>>> cyl              Cylindrical Equidistant
>>>>> omerc            Oblique Mercator
>>>>> aea              Albers Equal Area
>>>>> spaeqd           South-Polar Azimuthal Equidistant
>>>>> ortho            Orthographic
>>>>> cass             Cassini-Soldner
>>>>> splaea           South-Polar Lambert Azimuthal
>>>>> robin            Robinson
>>>>>
>>>>> Phillip     
>>>> Philip:  I think Andrew meant nsper is in proj4.  I'll look into 
>>>> adding support for it in Basemap.
>>>>
>>>> -Jeff
>>>>
>>> Thanks!
>>
>>
>


-- 
Jeffrey S. Whitaker         Phone  : (303)497-6313
Meteorologist               FAX    : (303)497-6449
NOAA/OAR/PSD  R/PSD1        Email  : Jeffrey.S.Whitaker@...
325 Broadway                Office : Skaggs Research Cntr 1D-113
Boulder, CO, USA 80303-3328 Web    : http://tinyurl.com/5telg