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2

It looks like your raster has some very odd low values associated with it: These values are clearly not related to the rest of the data and they fall along the very edges of the dataset. Not even setting the lower value to 0 or copying the lower value into the additional No Data value seemed to work. It is almost certainly this that is causing the ...


2

I know this is an old post, but it showed up on Google for something I was looking for, so I thought I'd post my solution. I don't see this as a 2D curve fitting exercise, but rather a 3D one. By considering the data as 3D we can ensure that the curves never cross one another, and can use information from other contours to improve our estimate for the ...


1

Depending on the size of your area you could convert your contour lines into polygons and then colour them using a patterned fill. This might be very slow on a large area with lots of contours. I've tested it using a simple fill on a small area: Because the polygons will overlap each other you would have to use symbol levels to stack them correctly (See ...


7

You can specify levels using the GRASS module, r.contour.level. It's available in the processing toolbox. You can search for it when the dropdown at the bottom of the Processing Toolbox window is switched from "Simplified interface" to "Advanced interface". The "List of contour levels" parameter takes a comma separated list of elevation levels. Here is ...


2

If you make contours everywhere at some interval or set of intervals that includes all the elevations you want, you can then extract only those elevations from your whole set of contours to a new shapefile. To do that, go into the attribute table and select features by expression. Use an expression something like: "ID" >= 50 AND "ID" <= 75 where ...


0

If line to polygon does not work, try checking the topology and look for mistakes. Contour lines are not always closed, you could try closing them before you try the line to polygon.


1

Turns out this is a spatial indexing issue. Apparently the Feature Outline tool creates incorrect spatial indexing and turning off the spatial indexing for the mask feature class makes everything work right.



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