[Qgis-user] IR-airphoto and 3D

[Dr. Markus Weidenbach]

Hi ,

there are also some GRASS modules like i.ortho.photo, which might be an 
option (note: yet they are neither included in the native windows 
version of GRASS nor in QGIS for Win).
I yet have no experience with it, but maybe this paper gives the 
necessary insight: 
http://www.nceas.ucsb.edu/files/scicomp/GISSeminar/GrassImageProcTools.pdf

Regards,
Markus


Mats Elfström wrote:

> Hi all!
>
> I agree, this software effort seems interesting enough to take a 
> closer look at. However, I notice that the material on the website is 
> not updated since 2008. I wonder why?
> Anyway, as an experienced photogrammetrist, I know that you need more 
> than two random shots with sparse geometric info to create an oriented 
> stereomodel. You mention corner coordinates. Do you have the ground 
> elevation for these as well? Do you know the lens data? Ground control 
> points?
> OK I know that you can compute a semblance of a 3D model from a  
> number of random shots, but that will only be valid in it's own 
> context without ground control.
> See if you can drape the images on the Google Earth surface? That may 
> give you an idea of the topography if your area is not too small.
> I would suggest you follow the advice to obtain a ready made surface 
> to drape your image on.
>
> Regards, Mats.E
>
> 2010/4/27 Ulf Almroth <ulf.almroth at lillabjoern.se 
> <mailto:ulf.almroth at lillabjoern.se>>
>
>     Johan,
>     What you need is a photogrammetric package. I only know one open
>     source package. Look at http://www.efoto.eng.uerj.br/en:start and
>     download the latest version. It has all you need to accomplish
>     your task, includning a modul for DEM (digital elevation model)
>     extraction from the stereo pair. Yoy dont need dual screens, fancy
>     cards and polaroid glasses. A split screen or re/blue glasses like
>     som childrens books had when I was a kid will do. Note: I found
>     this package recentlly and had no time to test it, but I am going
>     to. There used to be another free package,  photomodeler, but i
>     don't think it is free anymore and anyway it is phocused on
>     terrestrial and not on aerial images.
>
>     Ulf Almroth
>
>
>     ----- Original Message ----- From: "Johan Nilsson"
>     <joni8135 at gmail.com <mailto:joni8135 at gmail.com>>
>     To: <qgis-user at lists.osgeo.org <mailto:qgis-user at lists.osgeo.org>>
>     Sent: Monday, April 26, 2010 3:01 PM
>     Subject: [Qgis-user] IR-airphoto and 3D
>
>
>
>         I have very little knowlight of terminology in this area.
>
>         Is there a possibility if you have 2 semi-overlapping
>         IR-photo, with
>         known flight-altitude, distance between picture, camera-model and
>         pictures corners coordinat, to make a 3D model with height-data?
>
>         To use 2 pictures to get "stereo-vision", requere quite special
>         dual-screens and gfx-card and polaroid-glasses, so to skip
>         this, are
>         there some other software that can pick altitude for every
>         pixel in
>         the area  there 2 IR-photo cover?.
>
>         If not QGIS have this, is there any other open
>         source-applications to
>         use, for instance GRASS that manage this, and what is the name
>         of the
>         process to make a 3D-map from at leaste 2 airphoto in
>         GIS-terminology?
>
>         /Cheers
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>
>
> -- 
> ______________________________________________
> Mats Elfström, Väpplingvägen 21, SE-227 38 LUND, Sweden
> tel: +46 46 145959 / mob: +46 70 595 39 35
> alt e-mail: mats.elfstrom at telia.com <mailto:mats.elfstrom at telia.com>
>
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