Would it be possible to calculate these parameters with a panoramic creation package like panotools? <br><br><a href="http://wiki.panotools.org/Lens_correction_model">http://wiki.panotools.org/Lens_correction_model</a><br>
<br>It calculates a value for field of view, but I didn't notice an actual focal length parameter. Maybe this is easy to associate?<br><br>One benefit is that you are calculating using image overlap, which may be easier than trying to reference to a recent photo. <br>
<br>-Jamie<br><br><div class="gmail_quote">On Thu, Apr 10, 2008 at 9:53 AM, Vincent Bain <<a href="mailto:bain@toraval.fr">bain@toraval.fr</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
May it be a stupid suggestion, but did you try to contact anyone at the<br>
USGS ? perhaps they maintain data from these old times... (here in<br>
France IGN is always helpful, and can provide answers to such historical<br>
requests)<br>
<br>
Vincent.<br>
<br>
Le jeudi 10 avril 2008 à 18:33 +0200, Markus Neteler a écrit :<br>
<div><div></div><div class="Wj3C7c">> On Thu, Apr 10, 2008 at 5:29 PM, Shaun & Melissa Busler<br>
> <<a href="mailto:buslers@gmail.com">buslers@gmail.com</a>> wrote:<br>
> > Unfortunately, the focal length of the camera is not on the photo border.<br>
> > The photo must be too old. Do you have any recommendations on what focal<br>
> > length I should try? It was taken in 1939 for the USDA Agricultural<br>
> > Adjustment Administration.<br>
><br>
> You could try 150mm or 305mm. In fact, i.ortho.photo is quite robust,<br>
> just try and hope that it converges.<br>
><br>
> (and/or: Maybe someone on the PROJ4 list knows.)<br>
><br>
> Markus<br>
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