[Talk-GB] Aerial Photography

[John Robert Peterson]

Part of the idea of this project was to kick start thinking about this sort
of thing.

The ideal situation for me would be if we could have some automated tool on
a sever somewhere receiving images from users, and automatically rectifying
them.

This sounds imposable, but I believe that with a very small amount of user
help it could work:
Images can be automatically pinned together in overlaps (and high res images
can be pinned onto wide area images) using tools similar to those in
Panorama Tools / hugin (this searches for notable points in the image data,
and matches them between images);
searching the images for road markings (and/or cars) and matching these to
the gps traces already uploaded would give a reliable enough way to add real
world control points;
if a concept of altitude is added, automatic control points between images
appearing on top of skyscrapers would not be too damaging;
approximate terrain relief for most of the planet is already known, this can
be tied into the above to help;
manually adding control points would be done by displaying already rectified
images next to a map, with the user adding pins to useful points;
images with no rectification data at all would be added using a push pin
system similar to that used on http://warper.geothings.net/

the above is a pipe dream at the moment, but has the potential to
revolutionise how we do things in my opinion.

Any further ideas on this?

The images of stratford were taken mostly angled, with a few almost
vertical. we spiraled around the town and I took images out the downward
facing window, it seemed to work pretty well (if the results are a little
chaotic)

mapping from these images is the million dollar question -- the raw images
are going up online at
http://www.flickr.com/photos/thingomy/collections/72157622345143470/ and are
fine for visual reference while mapping, but rectifying them is a more
tricky issue.

JR


2009/9/14 Tristan Thomas <tristan.thomas at wikinewsie.org>

>
> Many of the photos taken above Stratford upon Avon seem to be taken at an
> angle-how do people find them for mapping from?
>
>
> 2009/9/14 Chris Hill <osm at raggedred.net>
>
> I used to hold a pilot's licence and I did some work photographing
>> archaeological sites.  Photos taken pointing sideways are much harder to
>> work with than photos pointing straight down. Any kind of rectification adds
>> unwanted artifacts.  I used to make high bank angle turns (60' bank angle)
>> over the feature I wanted to photograph which made it very easy to
>> photograph.
>>
>> I was trying to photograph a small area in detail, so circling over the
>> feature helped.  I was also using film (before widespread hi-res digital),
>> so there was a limited stock of film but the resulting image was the
>> equivalent of about 25mp.  To reduce parallax I used a telephoto lens.
>>
>> It gives a very interesting overview, but it's not a patch on surveying on
>> the ground where you have access.
>>
>> Cheers, Chris
>>
>> Tristan Thomas wrote:
>>
>>> I would be very interested to hear what people think of this effort.  I'm
>>> currently studying to be a pilot & I know that many people who do fly
>>> routinely take aerial pictures of the landscape below, especially of towns
>>> etc.  I know most of them would be more than happy to allow their photos to
>>> be used of OSM.  If we could find a way to upload them somewhere, then I'm
>>> sure we could dramatically increase the aerial photography we have without
>>> having to pay to hire the planes or get it sponsored.  I could just upload
>>> them all under one Flickr account for OSMers to look through & do some
>>> tracing if they wish, but it doesn't seem the most efficient way to do it?
>>>  Thoughts?
>>> ------------------------------------------------------------------------
>>>
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>>
>>
>>
>
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