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I need to find out the time a bird spends in different areas within a windpark.

I have a shapefile (flight lines) with the following attributes: enter image description here

"presence" is always = 1, the times represent the length of a single flight path (how long it was recorded at least)

So far I have converted this vector to a raster file, where each cell (grid cells need to be 250x250m) has either a value of 1 or 0 (1 if a line crosses through it and 0 if not). However I need to assign more values to the cells depending on how many times the bird passes through and how much time is spent in each cell.

The specific rules I need to follow are:

  1. A cell gets 1 point (I'll call them points) each time a line (the bird) passess through. So if the bird flies into a cell, leaves and flies back through, then that cell should be rated as a "2".
  2. Often birds will spend long periods of time within a cell without crossing cell boundaries. In this case, for each minute spent within the cell boundaries, 1 point is given. So if the bird flies around in one cell for 3 minutes, then the cell gets a "3".

The tricky part is that both the crossing and circling inside may be happening within the same cell at different times. So a cell with 3 minutes of circling and 1 cross through should be given a "4". Below is an ex. of what it should look like with labels.

The second step is calculating some kind of average based on the final cell values, but I only seek help here to set up the raster so that is has the values I need.

Here is an example version of the flight lines for testing

enter image description here

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  • What if a bird flies in, spend 40 s inside, then flies out and in and spend 30 s. Is that a "time" point?
    – BERA
    Jan 25, 2022 at 18:51
  • Good question, no. This would just be the 2 points for crossing the boundary twice as I understand it. Unfortunately the guidelines I am following are not so clear (and in German).
    – Chente
    Jan 25, 2022 at 20:29
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    Is each line (flight path) broken into multiple segments where it enters the study area buffer?
    – Aaron
    Jan 25, 2022 at 21:49
  • All the paths are within the buffer. Each lines in the table shown respresents a single segment. In the file I provide there are 100 segments.
    – Chente
    Jan 26, 2022 at 7:07

1 Answer 1

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I assume your data is vector format (not raster)

The second step is difficult to solve without having your data.

The first step can be solved with:

  1. Intersect grid with bird paths
  2. Multipart to singlepart
  3. Statistics by categories to count the occurences of each grid id. Use grid as "Field(s) with categories"
  4. Join the result back to the grid

enter image description here

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  • The data is vector format, but the method I planned to use invloves converting in into a raster. I will edit the post and include a similar vector file + buffer polygon to make it easier to replicate.
    – Chente
    Jan 25, 2022 at 20:34
  • I don't understand the method you describe above, perhaps you could give me a little more detail?
    – Chente
    Jan 26, 2022 at 7:29

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