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lmotta edited this page Mar 11, 2019 · 11 revisions

Gimp Selection Feature Plugin

Gimp Selection Feature makes it easy to create polygon from image using the Gimp selection tools.

The Gimp Selection Feature is a panel plugin that permit send the image of view of map to GIMP, and, get the region selected by GIMP how a feature in QGIS.

Steps:

  • Open GIMP :
    Run IBAMA plugin alt-text-1
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  • Send image to GIMP :
    Mark the visible images that you want send to GIMP. Of course, the images need be neighbours.
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  • Select region in GIMP :
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    Use the tools for select a region inside image.
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    Select the tool that you want.
    In example, the "Fuzzy Select" tool and removes the holes.
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  • Get features :
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    The button "Get Features" get the selection region how a feature in QGIS, creating the "gimp_selection" layer(polygon) if not exists.
    The settings:

    • Annotation: The text to use for identify the polygon.
    • Remove area: The maximum size of area that will be remove.
    • Remove vertex: The limit angle between neighbours vertex, below this value the vertices will be remove.
    • Smooth(Chaikin algorithm):
    • Level: Number of interations.
    • Fraction of line: Percentage of line to begin create vertex.
    • Ajust the borders: Remove overlap and gap between the borders between the new and the exists geometries.

  • Getting the first feature:
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  • Increase the "Remove area"(500 pixels), "Remove last features" and "Get features" again:
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Attributes of gimp_selection layer:

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  • id_add: The index of the feature added.
  • total_imgs: Total of images sent to GIMP.
  • images: The list of image(name and source)
  • user: The name of user of machine.
  • date_add: The date of the feature added.
  • crs_map: CRS of map when the image was sent.
  • extent_map: The extent of map when the image was sent.
  • annotation: The text typed when the image was sent.
  • area_ha: The hectare of geometry(it is a virtual field)
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Considerations:

  • The GIMP version tested was 2.10.8.

  • The CRS of 'gimp_selection' layer is EPSG:4326

  • If gimp_selection layer is visible, it is can send together with images.
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  • Example of "Adjust the borders"

    • "Send image" with 'gimp_selection' layer.
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    • Create a selected region Create a selected region that is neighbor of other in Gimp.
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    • Get features without adjust(Overlap and Gaps).

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    • "Remove last features", "Adjust the borders" and "Get features" again.

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