[GIS] Creating GeoTIFF from TIFF using GDAL

command linegdalgeotiff-tiff

I have a tiff image and I would like to georeference it, and so create a Geotiff. To do that, I have to use GDAL. I use in particular, the executable store in the QGIS file (gdalwarp.exe, gdaltranslate.exe…).

For now, I use this code in a DOS command (command line), and this doesn't seem to work.

gdal_translate -of GTiff -gcp 33.9983 669.668 -833589 -692.339 -gcp 124.661 1377.97 -833520 -1379.2 -gcp 6788.34 -10.2993 -826876 6.06375 -gcp 6839.33 748.997 -826813 -755.83 -gcp 3014.52 363.682 -830651 -363.339 -gcp 3892.81 1032.32 -829762 -1021.34 "D:/Users/(...)/Desktop/image_projetee_UTM.tiff" "C:/Users/(...)/AppData/Local/Temp/image_projetee_UTM.tiff"

gdalwarp -r near -order 1 -co COMPRESS=NONE -dstalpha "C:/Users/(...)/AppData/Local/Temp/image_projetee_UTM.tiff" "D:/Users/(...)/Desktop/image_projetee_UTM_georef.tif"

1 – After run this code, the output image is not a GTiff but a Tiff like the input image.

2 – If I try to open the output image in Google Earth for example, it doesn't seems at all georeferenced

I think I missed something in the way to georeferenced a Tiff file…

Can anyone help me ?

Best Answer

So, I succeed to georeference a tif file with GDAL with the use of 4 gcps (ground control points). To do this reprojection, I use gdal in command line.

First, use gdal translate like this : 

gdal_translate -of GTiff -gcp 0 0 -6.848326  45.501053 -gcp 6862 0 -6.490975 45.501503 -gcp 0 1379 -6.762872 45.377363 -gcp 6862 1379 -6.545354 45.382523 "Inputimage.tif" "OutputImage.tif"

The ground control points are build like this : pixel coordinate in the image (x, y) and then geographical location (longitude, latitude).

I suggest to check with gdalinfo if the output file after gdaltranslate has been correctly fed with the gcps. With gdalinfo, you have to see in dos command something like that : 

Coordinate System is `'
GCP Projection =
GCP[  0]: Id=1, Info=
          (0,0) -> (45.501053,-6.848326,0)
GCP[  1]: Id=2, Info=
          (6862,0) -> (45.501503,-6.490975,0)
GCP[  2]: Id=3, Info=
          (0,1379) -> (45.377363,-6.762872,0)
GCP[  3]: Id=4, Info=
          (6862,1379) -> (45.382523,-6.545354,0)

At this point, the image is not georeferenced yet. You have to use gdalwarp like this (there is several way to reproject, here I use "near" : 

gdalwarp -r near -order 1 -co COMPRESS=NONE -dstalpha 
"OutputImageF_From_gdal_translate.tif" 
"FinalImage.tif"
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