[GRASSLIST:3429] Re: Fw: Images resolution and rectification.

[giorgio]

Hi
Ok Ok!  The four vertices of the image are expressed in geodetic latitude
and longitude  but the projection of my image (Level 1B) is  UTM, you can
load it in the metadata of the hdf file searching for:
· SCENEFOURCORNERS
· MAPORIENTATIONANGLE
· PROCESSINGPARAMETERS (Projection information)
MPMETHOD
UTMZONECODE
RESMETHOD
so  you need to convert lat long   to obtain the UTM coordinates of four
vertices and after to rotate the image of an angle= MAPORIENTATIONANGLE.
I have used the m.ll2u using WGS84 as spheroid to get the UTM cordinates and
i.rectify to rotate the image in the space.
Something of wrong???
Many thanks
GIORGIO

----- Original Message -----
From: "Markus Neteler" <neteler at itc.it>
To: "giorgio" <giorgio19291 at inwind.it>
Sent: Wednesday, April 03, 2002 11:20 PM
Subject: Re: [GRASSLIST:3421] Re: Fw: Images resolution and rectification.


> On Wed, Apr 03, 2002 at 10:20:02PM +0200, giorgio wrote:
> > Hi Markus
> > All Level 1B and higher-level data products of aster data are projected
in
> > UTM you can get them ftom http://edcimswww.cr.usgs.gov/pub/imswelcome/.
I'm
> > not sure but, maybe, aster 1A level too.
>
> Mhhh, I have downloaded numerous ASTER from that site, but all are
> in Lat/long, not UTM. Which software did you use to get the UTM
coordinates?
>
> > Something about the lost of resolution with the rotation (rectification)
of
> > the image??
>
> It's unusual - normally, when data are geocoded, no further rotation is
> needed (or use r.proj to keep the resolution).
>
> If you tell me where to get these UTM coordinates I try to
> help you. Just today I was trying to import an ASTER image with my
> new (upcoming) r.in.hdf. But coordinate handling is not finished yet,
> so I need a hint for UTM.
>
> Thanks,
>
>  Markus
>
> > Thanks a lot in advance!!
> > Giorgio.
> > ----- Original Message -----
> > From: "Markus Neteler" <neteler at itc.it>
> > To: "giorgio" <giorgio19291 at inwind.it>
> > Sent: Wednesday, April 03, 2002 5:35 PM
> > Subject: Re: [GRASSLIST:3399] Fw: Images resolution and rectification.
> >
> >
> > > Hi giorgio,
> > >
> > > On Sat, Mar 30, 2002 at 10:51:48AM +0100, giorgio wrote:
> > > >
> > > > ----- Original Message -----
> > > > From: giorgio
> > > > To: grass5 at grass.itc.it
> > > > Sent: Saturday, March 30, 2002 10:45 AM
> > > > Subject: Images resolution and rectification.
> > > >
> > > >
> > > > I have an aster image.
> > > > Reading information on this kind of images: these are already
projected
> > in utm coordinates with 15m pixel resolution but are roted in the space
for
> > trayectory of satellite.
> > >
> > > just curious, where did you get them in UTM?
> > >
> > > Markus
> > >
> > > > So I have imported it in xy grass envirnment and rectified it with
the
> > four utm coordinates readed from data associated with images.
> > > > The results is a good registration of image but a lost of resolution
> > 15-->20m pixel.
> > > > There is a method to mantain the resolution of the image??
> > > > Many thanks Giorgio.