Hi Milena,
There's an algorithm "Random Points in Polygons" that will only return
points within the polygons of a layer. So you need a vector layer for
land for the area you are interested in.
Hope this helps,
Raymond
On 14-04-2021 08:36, Milena Muehler wrote:
Dear community!
I’m new to QGIS and hope you can follow my process and my question. Would be
more than happy to get your help!
So I have a raster layer with a cumulative value for each raster giving
information about land modification (in 2016)
I have another vector layer with points providing information where an outbreak
of a zoonotic infectious disease occurred (in 2016)
I want to examine the effect / association between land modification and outbreak
(I´ll do this with a binary logistic regression analysis in SPSS) therefore I want
to generate a text file with values of the land modification for the location of the
outbreak - I’ve done this with the tool "point sampling“.
But I also need values of land modification located at the points
„no-outbreaks“. (to calculate the binary logistic regression analysis later in
SPSS) Therefore I’ve generated random points. However, these points are truly
random :)
So most random point „lay in the ocean“ and therefore I don’t get values of
land modification.
So my question: How do I deal with that? Can I give a kind of command that all
random points have to lie on land? and to give a certain radius for the „not
random“ points - outbreaks.
someone said I can do this via raster calculator. But I cannot follow it, since
I don’t calculate two raster layers?! I gave me this kinda command to deal with
my issue: (via raster calculator?!)
L = grid cell is on land
B = Buffer around outbreaks with radius r (tbd: minimum distance between
outbreaks and random non-outbreaks)
D = L / B (difference "L without B „ = country on which a random non-outbreak
can lay)
Thank you so much!!!!!!!
_______________________________________________
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
_______________________________________________
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
