I have a very old file while contain contour lines. And then I obtained a new DEM from which I generated new contour lines. Visually I can see that between 2 files, the contour lines of the same elevation differ in distance and they differ from one elevation to another. Is there any way I can get a statistical result about max, min, mean between these files? And is it possible to visualize this?
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How to compare old contour lines and new contour lines?
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Best answer by redgeographics
Exactly what kind of statistics would you like? Min/max/mean elevation within the entire dataset?
To see the specific differences you can try a ChangeDetector (although my bet is that all contour lines will differ). As for visualisation, you can do that by picking 2 colors and showing both on a single map. An alternative visualisation is to pick the new DEM and create one from the old one, then create a grid, drape that over both DEM's and show the areas higher or lower with different colors.
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- Best Answer
Exactly what kind of statistics would you like? Min/max/mean elevation within the entire dataset?
To see the specific differences you can try a ChangeDetector (although my bet is that all contour lines will differ). As for visualisation, you can do that by picking 2 colors and showing both on a single map. An alternative visualisation is to pick the new DEM and create one from the old one, then create a grid, drape that over both DEM's and show the areas higher or lower with different colors.
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redgeographics wrote:
Exactly what kind of statistics would you like? Min/max/mean elevation within the entire dataset?
To see the specific differences you can try a ChangeDetector (although my bet is that all contour lines will differ). As for visualisation, you can do that by picking 2 colors and showing both on a single map. An alternative visualisation is to pick the new DEM and create one from the old one, then create a grid, drape that over both DEM's and show the areas higher or lower with different colors.
Nice job!
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redgeographics wrote:
Exactly what kind of statistics would you like? Min/max/mean elevation within the entire dataset?
To see the specific differences you can try a ChangeDetector (although my bet is that all contour lines will differ). As for visualisation, you can do that by picking 2 colors and showing both on a single map. An alternative visualisation is to pick the new DEM and create one from the old one, then create a grid, drape that over both DEM's and show the areas higher or lower with different colors.
Hi @Hans van der Maarel
Sorry about the late reply. I am looking for the min/max/mean difference between the 2 files in terms of XY position for the same elevation. I have done your first suggestion initially and then I wish to be able to work with my data furthermore. So the visualization I am targeting is to be able to show this difference, which areas have little difference and which areas have big difference and how big are the differences from one area to another.
As for your alternative suggestion, I have been thinking about it too, but have not tried it yet. Thanks for suggesting it and thereby confirming this possible solution.
My student license has expired and I hope to get a new one, so I will come back here later if I get a new license.
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redgeographics wrote:
Exactly what kind of statistics would you like? Min/max/mean elevation within the entire dataset?
To see the specific differences you can try a ChangeDetector (although my bet is that all contour lines will differ). As for visualisation, you can do that by picking 2 colors and showing both on a single map. An alternative visualisation is to pick the new DEM and create one from the old one, then create a grid, drape that over both DEM's and show the areas higher or lower with different colors.
finally! The whole process went through different transformers... rasterresampler, clipper, rastercellvaluecalculator to finally a geotiff that shows areas of high to low elevation changes.
However I was not able to create any grid.
Thanks for great tips!
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