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I'm using Monteverdi 2 to perform a mean shift segmentation on an image of an archaeological dig, to test the feasibility of automatic detection of elements.

I've loaded the image in Monteverdi and defined the export feature shapefile, with all other parameters as default. The resulting shp polygon features, when viewed in QGIS, are flipped vertically as so: original image and flipped shapefile

Why does this happen?

  • what is your input image type? sometimes, the georeferencing information is stored in two places and different softwares don't give the same priorities when readin it. In your case, it seems that the pixel size in Y is interpreted as a negative value by QGIS and a positive value with Monteverdi. Is is a geoTiff with a .geom or .tfw file? Something else? – radouxju Dec 26 '13 at 19:42
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there is a thread in the otb user mailing list which give a workaround for this issue:

https://groups.google.com/forum/#!search/mean-shift$20segmentation$20few$20comment/otb-users/fQ4yxjA_LbM/1lsmAnd3XE0J

It is related to the fact that qgis is doing something specific when the input image does not have an origin. The workaround is to make an extract from the imput image from pixel coordinate (1,1) using OTB extractROI application: otbcli_ExtractROI -in input.jpg -out output.tif uint8 -startx 1 -starty 1

It will add an origin to the image, then you can perform the segmentation and the result will not be flipped anymore in QGIS.

Hope it helps.

Manuel

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