[OSM-talk] Using GeoBase images for openlayers for OpenStreetMap and OpenAerialMap

andrew heggie list at sylva.icuklive.co.uk
Mon Dec 22 21:11:54 GMT 2008


On Monday 22 December 2008 14:21:25 Jukka Rahkonen wrote:
> > I thought I was clever enough to upload 17 aerial photos of my home town
> > to which I have paid for free use (copyright retained by the aerial
> > photography firm) but when it came to complications of georectification I
> > stalled. So I agree a bit more help would be useful except how many
> > people have use of such photos? Mine are 4MB jpegs and with overlap they
> > cover about 5km by 5km.
>
> If you can acquire ground control points in some way I believe I could
> guide you a bit further.  What you should do first is to find a few points
> from each image and measure the image coordinates (row and column of a
> pixel) and real world coordinates for that same pixel in some known
> projection.

I can do that by choosing 4 identifiable points (a railway bridge over a road, 
two roundabouts and a large fuel tank) which are near the 4 corners of an 
image. I can survey each of these points with a gps. I'll do this over the 
next few days rather than read them off another map.

AJH




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