[Qgis-user] IR-airphoto and 3D

[Mats Elfström]

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>

> 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>
> To: <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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>
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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
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