[OSRS-PROJ] SOM-A

[Clifford J Mugnier]

John originally published his SOM the same month I published a paper on
single-ray rectification in "Photogrammetric Engineering."  I think it was
'77 or '78.  (You know you're getting old when you can't remember the
year).  Anyway, I've got some of John's old typewritten and handwritten
manuscripts as well as his hardbound USGS volume on his SOM.  No, you can't
have it.

However, let me know what details you think you need, I'll copy or scan
them and mail them to you.

Cliff Mugnier
LOUISIANA STATE UNIVERSITY

-------------------------------------

Oh boy!  The only amount that I have looked at it was many years ago and
that was only to check that it could replicate JPS' test numbers.  I
will give it
a quick look and see if I understand any of it.

At the moment I am about half way through omerc and trying to figure out
a computation in gctp/prpj that is not documented anywhere.  BTW, EPSG
is
*not* a very good code source.  What is in there is basically JSP'
workup
but lacks some critical details.  It is not from Hotine.

On Jan 23, 2004, at 4:45 PM, Frank Warmerdam wrote:

> Gerald Evenden wrote:
>> Space obl.. merc is in PROJ.4, basically a copy of gctp.
>> +proj=lsat
>
> Gerald,
>
> It's embarrassing what I don't know sometimes.  I see it is driven by
> the lsat (presumably land sat number) and path values much like the old
> GCTP formulations I have seen.  Would it be hard to update the code to
> support the explicit parameters JPL is suggesting?
>
>  3 Inclination of orbit ascending node.  (angular units)
>  4 Longitude of ascending orbit at equator.  (angular units)
>  7 Period of satellite revolution.  (time in minutes)
>  8 Satellite ratio.  This controls the start and end points of the
> map on
>     the earth surface.
>
> My presumption is that these are being computed internally from the
> landsat
> number and path ... is that right?  Are these JPL guys going at the
> problem
> in a good way to reduce the projection to it's underlying parameters
> or is
> it just going to make it a huge hassle for people to enter?
>
> Best regards,
>

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