orthorectification,aerial photographs

[Justin Hickey]

Hello Radoslav

On Sep 8,  6:49pm, Radoslav Bonk wrote:
> Subject: orthorectification,aerial photographs
> >my GUESTION is: 1. Are the GRASS tools for orthorectifying an aerial
> photos suficient to get a good results?
>                  2. What are the steps of such an image processing?
>                  3. I have compiled r.in.tiff I think I will need it for
> image processing. Will I?
>                  4. Where I can find a similar project or www paper with
> >    solving the problems of Orthorectifying the aerial photos?

Sorry I can't answer number 1 for you except to say that the i.rectify program
seemed to work fine for us. You should look at the man pages for the following
programs which are used in rectifing images:

	i.group
	i.target
	i.ortho.photo 	(I think this is what you want but I've never used it)
	i.points
	i.rectify
	i.rectify2

When we rectified our image, we used i.group, i.target, i.points, then
i.rectify. I think for i.ortho.photo you might need to do an i.group, i.target,
then i.ortho.photo. I'm not sure and someone can correct me if I'm wrong.

The r.in.tiff command did not work for us at all. Instead we used r.in.gif that
is found in $GIS/src.contrib/SCS/raster/r.gif/ where $GIS is the GRASS root
directory. Unfortunately, there's no man page for it but there is a usage
message when you run the program with a dummy argument, or you can run it
interactively. Note that to compile the r.in.gif command you may need to make a
minor change to the file $GIS/src.contrib/SCS/raster/r.gif/cmd/Gmakefile,
depending on how picky your linker is (ours was picky). The change is to simply
add "$(MATHLIB)" (without the quotes) to the end of line 8. It should be as
follows:

	$(CC) $(LDFLAGS) -o $@ $(LIST) $(GISLIB) $(EXTRALIB) $(MATHLIB)

As for question 4, I have no idea.

I hope this helps and maybe someone else on the list who actually used
i.ortho.photo can offer more or better advice. Good luck.

-- 
Sincerely,

Jazzman (a.k.a. Justin Hickey)  e-mail: jhickey at hpcc.nectec.or.th
High Performance Computing Center
National Electronics and Computer Technology Center (NECTEC)
Bangkok, Thailand
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