serving multiple orbits as mosaic

[Ara T Howard]

hi all-

we're curently serving dmsp sat data, which are full polar orbits, as a
pre-made mosaic.  this works well.

the current projection we're using is geographic which works well for a large
marjority of users.  however, it would desirable if one could actually make a
request for a polar projection and see, for example, the aurora ringing the
pole cap.

unfortunately the fact that we've dumped all the orbits into a single
geographic mosaic before hand means that at high/low lats only one or two
orbits will be respresented.

i'm still pretty new to mapserver, so perhaps this idea is simple or
impossible, but what i'd like to do is server each day's orbits as layers and
let mapserver do the mosaicing.  this obviously implies a request for a bbox,
multiple layers, and a projection.  the thing is the client will not know
which layers are required to cover a particular bbox or in which order to
overlay them.  it is possible, however that we could determine this
information.

i guess one approach would be to create a pseudo layer name, say 'F15200701'
where 'F15' is the satellite and '200701' is the day in question. the mapfile
would contain only this pseudo layer name.  once a request for a bbox and
projection was made we could dynamically determine which layers should
__actually__ be requested and in what order and server those with the given
bbox.

does this make any sense?  has anyone out there done anything similar?

kind regards.

-a
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