Global Mapper v25.0

Georeferencing an image with a single co-ordinate

NEV
NEV Global Mapper UserTrusted User

I have 30 vertical aerial photographs with an exact co-ordinated of the centre point of each. Can I display them using this co-ordinate only?

Best Answers

  • tikhpetr
    Answer ✓

    Of course! I hope you still remember the school geometry course?😀

  • CarrickCon
    Answer ✓

    Hi Nev,

    Without know what format are they, or where the images have been taken, its hard to know how exactly to advise you. Unfortunately if you have no other georeferencing/scale/extents info about the images it will be hard to geo-reference them with a high degree of accuracy.

    Something you could try for +/- 1-2 m accuracy might be to use the Import Raster/Manually Rectify Image tool and manually reference it using whatever other linework or topo data you have for your project and selecting a minimum of three identifiable points for each image (>3 points would be better).

    You might even be able to manually reference it over ESRI World Imagery or World Street Map if you are completely stuck - I've done this in the past when a client gave me a bunch of hard copy aerial images of flooding in the WA Goldfields after Tropical Cyclone Bobby passed over the mine-site in question. I scanned the images and referenced them using road junctions, building corners, bore tanks, large trees etc. that were visible on both the images and World Imagery and the results were certainly accurate enough for flood mapping.

    If you are stuck, feel free to private message me via this forum @CarrickCon

    Cheers,

    /al

Answers

  • Of course, their georeferencing will be absolutely incorrect. If there is no additional data. For example, the azimuth of the flight.

  • NEV
    NEV Global Mapper User Trusted User

    Several of the photographs are consecutive so I can reconstruct the flight azimuth. From this, can I reconstruct the orientation of each image frame?

    Nev