Hi,

I have a series of image tiles covering a large area, and want to batch process them with a rule set I have created..  However, I am also using an NDSM in the rule set, but my NDSM covers the entire project area.  In the rule set, I want to add an algorithm which creates a scene subset the size of the current image (i.e. crops the NDSM to the size of the image) instead of having to pre-process the NDSM.  

In the "create scene subset" algorithm I thought to create variables for Xmin, Xmax, Ymin, Ymax that are the coordinates of my georeferenced image and will update with each new image in the batch process, but have not found a feature in the "update variable" algorithm which can do this for me.  Has anyone dealt with a similar problem before, or may have a solution? 

Thanks, Kate

2 comments

  • Michael Voltersen

    Hi Kate,

    one possible solution is to create your projects with a customized import routine (file>customized import). Set up the customized import as required and then click on the 'scene' tab and choose 'Scene extent>intersection'.

    Best regards,
    Michael

  • Loreena Jaouen

    Hi Kate, I'm not sure whether there is a feature to find the extent coordinates of specific image layers. I believe these features exist for maps, objects and vectors though.

    As a workaround, I usually create image objects spanning each of my tiles (e.g. using tile footprints with vector-based segmentation or nodata values with the multi-threshold segmentation) and assign classes from the tile number or ID. You can then use a class array and loop through each class to create a subset, either using the Xmin, Xmax, Ymin and Ymax from the active class, or by directly selecting the image object level and the active class in the "Create Scene Subset" algorithm, without specifying the coordinates.

    Alternatively, you could use the Customized Import tool to create eCognition projects for each tile. In the "Scene" tab (last tab), the tool gives you the possibility to specify the project extent as being either the union of all layers, intersection of all layers, or your master file extent (which in this case would be your tiles). The NDSM would then be clipped to match the extent of each tile in their respective projects and you can get working straight away. The downside is that you may struggle to stitch the tile results back together since the scenes are not considered as subsets, but as individual projects.

    I hope it helps a bit!

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