----------------------------Original message----------------------------
>
> ----------------------------Original message----------------------------
> Hello,
>
> Has anyone on the list ever digitized aerial photographs?
>
> Our aerial photos of Fresno Co.,Calif., are heavily used
> and it has been suggested that we undertake a project to
> digitize them.
>
> Does anyone have specific information relating to equipment
> and costs?  I would be very interested in hearing about the
> experiences anyone else might have had.
>
> Thanks in advance.
>
> Sue Haffner, Map LIbrary, CSU Fresno
> [log in to unmask]
>
Hi Sue,
Digitization of aerial photographs is done by scanners. The cost
of the scanner depends on the scanning resolution. and the
size of the scanner.  The scanning
resolution depends on what you are going to do with the digitized
image. Will it be used just for display or to perform measurements
on it? For the former you can use of-the-self scanners, where
you can almost fit the aerial photo (so scanning size and media
is important). The prize is in this case less than $5K if I
remember correctly and the scanning resolution can be between
300dpi to 600dpi.In case that you will use the digitized photos
for measurements than depends on the accuracies you are
looking for. Some applications are OK with 600dpi scanning resolution.
Some not and then you have to go to a higher level scanning
systems (resolutions in the order of 1000dpi and better) but
the price is much higher, for example $50k and above.
We scan aerial photography (films in our case) at 1000dpi. It
takes about 25min per photo. Industry also does it at about
CDN $25 per photo.
Regards,
Costas Armenakis
Canada Centre for Mapping