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Home - General / All posts - Clipping DEM rasters with a drawing (Manifold 9)
NithField6 post(s)
#27-Jun-18 21:57

Hello everyone, just starting with Manifold 9, so Im learning as I go.

I want to "clip" a DEM image to fit the drawing of the province they are in. The tiles of the DEM hang over the drawing boundary.

I cant seem to find the process to simply select the DEM layer by the Drawing polygon.

See the attached image as a reference,

Attachments:
DEM_clip_by_Drawing.png

Dimitri


4,991 post(s)
#28-Jun-18 06:41

I cant seem to find the process to simply select the DEM layer by the Drawing polygon.

That's not a simple, pre-built command in 9, at least not yet (it's coming relatively soon, as you can see from the Edge builds moving forward on various raster facilities). For now, you have to do that using infinitely-complicated SQL to get to pixels within tiles and lots of other messy infrastructure issues. It will be far easier when automated.

NithField6 post(s)
#28-Jun-18 11:17

Thanks,

for now i will just move the layers in and out of Manifold 8 and 9 for those sort of tasks.

adamw

8,090 post(s)
#28-Jun-18 15:56

In 9, you can also reduce the rect of the image to hide the parts that you don't want - right-click the image and edit the 'Rect' property (the format is: [ xmin, ymin, xmax, ymax ]). It will take some guessing (subtract 100 pixels from xmax - no, no, that's too much, add 50 pixels back - etc), but you won't have to be turning layers on and off after.

You can create multiple copies of the same image referring to the same pixel values, but with different rects, images are very cheap. To do this, copy and paste just the image component without the table that stores the tiles.

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