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I imported water contamination data from surface water bodies from a CSV file. Each water body was georeferenced with a single pair of lat/long coordinates. Now I have a map full of individual points which are located somewhere at the border of a lake, river etc. I only have one point per surface water body (no contours or similar).

How can I manually draw a shapefile around the points (depict the surface water bodies) which has the same properties (attribute table) as the respective point?

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    I'm confused by your question. It sounds to me like you want to digitise the water bodies and then join the attributes from the csv table to them. Is that right?
    – Anonymous
    Commented Jun 1, 2017 at 14:33
  • Do you have a base map to work from so you know the size and shape of the water bodies? If so, is this basemap a georferenced image? If not, how will you know the correct size and shape of the features?
    – MappaGnosis
    Commented Jun 1, 2017 at 14:48

2 Answers 2

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I just sorted this out in the meantime.

Just draw polygons in a new layer above the points and then perform spatial joints via Vector -> Data Management Tools -> Join attributes by location.

Select "contain" as Geometric predicate and select "all records" for a joined attribute table.

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You could use the edit tool which is available in QGIS. [QGIS documentation] (https://docs.qgis.org/2.2/en/docs/user_manual/working_with_vector/editing_geometry_attributes.html)

Create a new vector layer, polygon

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Click the edit toggle to start the edit session

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Then click on the add feature button to add your vertex to the map canvas

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You can add attribute information for as you create each individual body of water which will allow for a unique ID that you then can use to join to the CSV file as you already have.

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As well as modifying your table such as this:

enter image description here

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  • Thank you for your response. When i toggle editing, then the add feature button looks different for me. It's dotted because i can only add points which is not what I want do to.
    – Stücke
    Commented Jun 1, 2017 at 14:55
  • You will need to create a new vector feature that supports the polygon feature to create the shapes you want to represent the waterbodies. I've update my post to include the part.
    – whyzar
    Commented Jun 1, 2017 at 14:59
  • Thank you for your response. Not sure if i got this though. I created an additional layer with polygons which have the same ID as my points. However, if i save the polygon layer as CSV only the ID's are exported. No information about the shape. So if I merge the two CSV files I am actually where i started, or not? A CSV files with points and a lot of attributes but no shapes?
    – Stücke
    Commented Jun 2, 2017 at 11:39
  • Sorry, I just sorted this out in the meantime. You can just draw polygons in a new layer around the points and then perform spatial joints via Vector -> Data Management Tools -> Join attributes by location. Select "contain" as Geometric predicate and select "all records" for joined table. Anyway, thank you very much for your support!
    – Stücke
    Commented Jun 2, 2017 at 11:48

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