[GRASS-user] New modules in add-ons: v.in.geoplot, r.xtent + r.burn.frict

GRASS GRASS user
1

example:
http://bambi.otago.ac.nz/hamish/grass/screenshots/inlets_03_SurfSal_icw_big.png

sample data points are given with black diamonds. interpolation
must travel around islands and along channels.

ooh, that looks good. Very useful for interpolating data with faultlines,
I guess. However, quite the overkill for my little problem :wink:

by AA, do you mean like a 0 floor and 255 ceiling and depending
on how much vector line in the cell the output raster value
is somewhere in between (with length of cell diagonal == *1.0 ),
or is it still binary null || line_value but in a more smeary
way than normal?

I think suggestion #1 should be implemented in v.to.rast anyway,
as it would be a functional improvement for many use cases where
attribute values from vectors are to be transferred to a raster
with DCELL/FCELL type cells.

Your second suggestion would be an alternative, additional
method with its own uses. Easily implemented, I imagine,
by letting the user control the threshold (% of cell area
crossed by line) above which a cell should be set to "1"
(or whatever). In my scenario, a pixel should be placed,
whenever the % crossed area > 0.0.
The value to place could be the line value or an average of
neighbouring cells. Both may have applications.

Best,

Ben

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2

Hamish wrote:

> by AA, do you mean like a 0 floor and 255 ceiling and
> depending on how much vector line in the cell the output
> raster value is somewhere in between (with length of cell
> diagonal == *1.0 ), or is it still binary null || line_value
> but in a more smeary way than normal?

Ben:

I think suggestion #1 should be implemented in v.to.rast
anyway, as it would be a functional improvement for many use
cases where attribute values from vectors are to be
transferred to a raster with DCELL/FCELL type cells.

Your second suggestion would be an alternative, additional
method with its own uses. Easily implemented, I imagine,
by letting the user control the threshold (% of cell area
crossed by line) above which a cell should be set to "1"
(or whatever).

file a wish for anything which would be useful for you, otherwise
it will likely to be forgotten.

In my scenario, a pixel should be placed, whenever the %
crossed area > 0.0.

isn't this just the type=line or type=boundry/with category
method described in the v.to.rast help page?

The value to place could be the line value or an average
of neighbouring cells. Both may have applications.

use r.neighbors, then overlay 0/1 from line digitization as MASK?
(avoid duplication/complication in modules, they can be mashed
together in shell scripts to look like one module if needed)
?

Hamish