Re: [Geotools-gt2-users] Writing world files (TFW)

[Milton J. <mi...@cn...>]

Ciao Simone!

I tried to contact you by e-mail, but your server rejected my message 
twice. I'm thus answering your message through the list, ok?

Simone Giannecchini wrote:
  > <<WorldFileWriter>>
  > There is no such a thing in GeoTools, but it would be
  > easy+interesting to do it.
  >
  > Can you open upa JIRA for it and assign it to me so that I can
  > implement it?

OK: I'm not completely sure what's the right way to do this. I went to
jira.codehaus.org and opened an issue in the geotools project (I put it
as part of the "gc imageio" component). However, I did not find a way to
assign it to you.


  > (float, int, false colors) hence if you can detail a bit more your
  > requirements and provide some sample data

So let me explain what I want to do.

I'm working with multitemporal remote sensing image stacks. For that
matter, I often work analyzing the temporal behavior observed during an
entire year, and so a common example would be a 24-band raster data
file, where each band corresponds to the data observed every 16 days
(i.e., twice a month). Thus, in practice, I want to be able to access
any given (x,y) point within the image, and then analyze that point's
temporal behavior (i.e., z values). As a result of this analysis, I
usually write an output processed image such as a classification of the
data.

As far as I know, I cannot open and process 24-band Geotiff files with
Geotools, right? But what I CAN do is open and process these files with
JAI/ImageIO. My only problem then is that I lose the georeferencing
information, and my resulting output image comes out as a regular TIFF
file. My idea then was to simply use Geotools to read the georeferencing
info from the input file, and then write that to the output file
generated with JAI/ImageIO. One way to do this would be to write a TFW
world file (which you said is easy), another would be to write Geotiff
tags to the output regular TIFF image (which you said is quite harder). 
For me, any of these solutions would do fine.

Of course, the ideal solution is to have Geotools itself open and
manipulate n-band raster images, so I would say that there is absolutely
no sense in losing much time with any other workaround.

About the sample image, I have a small one with 24 bands (about 1MB) 
that I can send you. Please tell me where/how to send it, since your 
e-mail server doesn't seem to like me.. :)

Cheers, and thanks for the feedback!
Milton




Simone Giannecchini wrote:
  > Ciao Milton,
  >
  > <<WorldFileWriter>>
  > There is no such a thing in GeoTools, but it would be
  > easy+interesting to do it.
  >
  > Can you open upa JIRA for it and assign it to me so that I can
  > implement it?
  >
  > <<Geotiff Tags>>
  > At the moment is not that easy to write geotiff tags themselves in a
  > standalone tiff file.
  >
  > As above explain a bit better what you are trying to do and we'll
  > find a way to do it.
  >
  > <<MultibandRaster images>>
  > Well, it's not completely true that we do not support multiband
  > images. Truth is I focuse on 1-4 bands possibly with
  > intrinsic color interpretation. I starte playing a few weeks ago with
  > support for other types of data (float, int, false colors) hence if
  > you can detaila bit more your requirements and provide some sample
  > data we could maybe find out that you can already do most of you need
  > (am I being optimistic? :-) )
  >
  >
  >
  > Cheers,
  > Simone.
  > -------------------------------------------------------
  > Eng. Simone Giannecchini
  >
  > President/CEO GeoSolutions
  > http://www.geo-solutions.it
  > Via Carignoni 51
  > 550141 Camaiore (LU)
  > Italy
  > Mobile: +39 333 81 28928
  > -------------------------------------------------------

  > ----- Original Message ----- From: "Milton Jonathan"
  > <mi...@cn...>
  > To: <geo...@li...>
  > Sent: Monday, February 05, 2007 3:31 PM
  > Subject: [Geotools-gt2-users] Writing world files (TFW)
  >
  >
  >> Hello all,
  >>
  >> I would like to ask you (and especially Simone, since I think this
  >> is his turf), if there would be any way in which one could write
  >> georeferencing information separately from the raster data itself. I
  >> would imagine that the most straightforward way to do this would be
  >> to write a World File (e.g., a TFW file) using something like a
  >> "WorldFileWriter" class (there is already a WorldFileReader). As an
  >> alternative to World Files, one could think of writing Geotiff tags
  >> onto an existing TIFF file.
  >> Does anyone know if there is anything like that around?
  >>
  >> Now let me just explain why I want to do this: I'm working with
  >> multiband raster images, and, as far as I know, Geotools doesn't
  >> currently support that (it's planned for version 2.5, right?). This
  >> way, I was intending to process these multiband files using
  >> JAI/ImageIO, so that the output would be a non-georeferenced TIFF
  >> file. I would thus need to read the georeference info from the input
  >> file and somehow write that to the output file.
  >>
  >> Well, that's it then. Thank you all for any input on this one,
  >> Milton Jonathan
  >>