[GRASSLIST:3435] Re: Fw: Images resolution and rectification.

[Markus Neteler]

On Thu, Apr 04, 2002 at 10:11:33AM +0200, giorgio wrote:
> 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???

Mhhh, in my ASTER metadata I can only find
GRingPointLatitude
GRingPointLongitude
but nothing from above. However, it seems to be 1B data:
        OBJECT = ShortName
            Value = "AST_L1B"

Maybe you can put the metadata file into
ftp grass.itc.it
cd incoming
then I can look at it to get an idea.

Markus

> ----- 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.

-- 
Markus Neteler

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