[OSM-talk] Photo_mapping - How to put EXIF data into a jpg image

Craig Wallace craigw84 at fastmail.fm
Mon Feb 22 18:43:23 GMT 2010


On 22/02/2010 09:04, Liz wrote:
> On Mon, 22 Feb 2010, Jochen Plumeyer wrote:
>>   In our case of photo geo tagging this is no issue I think.
>> Please tell me if I'm wrong here.
>>
> For photo geo-tagging the main problem is that you can set the camera time to
> a resolution of one minute, not one second, and the camera time will drift,
> probably inversely related to the purchase price.
>
> So some form of fiddling is needed to accurately place the photos, trying a
> few secs forward and back until they line up on the map with known features.
> So whether your GPS is UTC or GPS time is not a practical problem.

The easy option is to take a photo of your GPS device with it displaying 
the time. You can then adjust the time offset from that.

I suppose there might be a bit of lag between the GPS device 
receiving/calculating the time, and displaying it on screen, plus lag in 
the time taken for the camera to save the photo, which might be a few 
seconds.

Though it shouldn't make a lot of difference in accuracy, unless you are 
taking photos while driving past at 50mph.

Craig




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