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I have a mini project to do which is to assign coordinates to each tiff image and later covert these images to ECW format. Im using Qgis 216 Nobedo. I have a txt file with the names of pictures and coordinates +pictures themselves. Is there a way I could assign coordinates to each picture on QGIS?

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    what are these images? are you georeferencing aerial photos or something similar? – DPSSpatial Oct 12 '16 at 20:39
  • Thank you for reply. I want to add spatial reference to each tiff. I do not have any ground control points apart from coordinates of each picture (which I assume is the centre of picture) – Benas Pekarskis Oct 12 '16 at 20:51
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You could use a worldfile file - a .tfw file in your case, which is a text file with a tfw extension. It's quite simple, but you need to know some info on the pictures : https://en.wikipedia.org/wiki/World_file

The generic meaning of the six parameters in a world file (as defined by Esri1) are:

  • Line 1: A: pixel size in the x-direction in map units/pixel
  • Line 2: D: rotation about y-axis
  • Line 3: B: rotation about x-axis
  • Line 4: E: pixel size in the y-direction in map units, almost always negative[3]
  • Line 5: C: x-coordinate of the center of the upper left pixel
  • Line 6: F: y-coordinate of the center of the upper left pixel

Example: Original falknermap.jpg is 800×600 pixels (map not shown). Its world file is falknermap.jgw and contains:

32.0

0.0

0.0

-32.0

691200.0

4576000.0

Or you could georeference those pictures with the georeferencer : https://ieqgis.wordpress.com/2014/05/22/how-to-georeference-a-map-in-qgis/

  • So if i create a tfw wordfile for a picture ,QGIS would understand that this picture has a spacial reference? – Benas Pekarskis Oct 12 '16 at 20:55
  • Sort of. The worldfile gives an equivalence of pixel based coordinate system to real world projection. You still have to tell QGIS what projection coordinates you're using. – gisnside Oct 13 '16 at 18:30

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