Re: [GRASS-user] Probabilistic neighborhood analysis
Hi Bernardo, On Mon, Jan 16, 2023 at 11:19 PM Bernardo Santos wrote: > > Hi Makus, > > Nice suggestion, I did not know about this function within r.mapcalc (it is > quite hidden!) Do you (or anyone else) have a suggestion how to make it more visible? Ideas welcome. thanks, Markus ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Probabilistic neighborhood analysis
Hi Bernardo, Yes, feel free to open a feature request issue. You can assign it to yourself if you think you may tackle it afterwards. Cheers, Vero El lun, 16 ene 2023 a las 19:20, Bernardo Santos via grass-user (< grass-user@lists.osgeo.org>) escribió: > Hi Makus, > > Nice suggestion, I did not know about this function within r.mapcalc (it > is quite hidden!) > I still do not know how to operationalize it, though. > For now, the solution with R worked, but it could be useful to have > something like that in GRASS in the future. > Should I open an issue with a suggestion? > (I do not have time to do it right now) > > Best > Bernardo > Em quarta-feira, 11 de janeiro de 2023 09:39:17 GMT+1, Markus Neteler < > nete...@osgeo.org> escreveu: > > > Hi Bernardo, > > Not sure if this helps but there is also this function in r.mapcalc: > > https://grass.osgeo.org/grass78/manuals/r.mapcalc.html > > graph(x,x1,y1[x2,y2..])convert the x to a y based on points > in a graph F > graph2(x,x1[,x2,..],y1[,y2..]) alternative form of graph() > > The graph() function allows users to specify a x-y conversion using > pairs of x,y coordinates. In some situations a transformation from one > value to another is not easily established mathematically, but can be > represented by a 2-D graph and then linearly interpolated. The graph() > function provides the opportunity to accomplish this. An x-axis value > is provided to the graph function along with the associated graph > represented by a series of x,y pairs. The x values must be > monotonically increasing (each larger than or equal to the previous). > The graph function linearly interpolates between pairs. Any x value > lower the lowest x value (i.e. first) will have the associated y value > returned. Any x value higher than the last will similarly have the > associated y value returned. > [...] > > Perhaps a dynamic (set of) graphs could be constructed? > > Best, > Markus > > On Wed, Dec 14, 2022 at 2:37 PM Bernardo Santos via grass-user > wrote: > > > > Hi, > > > > I am trying to produce scenarios of past land cover, before hydropower > reservoirs were built. To do so, I need to fill empty pixels from a raster > in the locations where the reservoirs are currently present, using as input > the actual land cover map. I tried doing that with r.neighbors (taking > method=mode) with neighborhoods of increasing size, to replace null pixels > with the most common land cover class in the neighborhood. I also tried > that with r.fill.stats which is basically the same thing. > > However, the results gets very homogeneous, since the interpolated null > cells always get the value of the most common land cover class. > > > > Do anyway know of a method in GRASS to perform a "probabilistic" > neirighborhood analysis, where cells in a neighborhood are given weights > (possibly related to the distance to the central cell and to their > frequency) and these weights are used to stocastically sample a value to > fill the central cell? > > If not in GRASS, does anyway know of such a method in a different > platform, i.e. R? > > > > Thanks! > > Best > > Bernardo > > ___ > > grass-user mailing list > > grass-user@lists.osgeo.org > > https://lists.osgeo.org/mailman/listinfo/grass-user > > > > -- > Markus Neteler, PhD > https://www.mundialis.de - free data with free software > https://grass.osgeo.org > https://courses.neteler.org/blog > ___ > grass-user mailing list > grass-user@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-user > ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Probabilistic neighborhood analysis
Hi Makus, Nice suggestion, I did not know about this function within r.mapcalc (it is quite hidden!)I still do not know how to operationalize it, though.For now, the solution with R worked, but it could be useful to have something like that in GRASS in the future.Should I open an issue with a suggestion?(I do not have time to do it right now) BestBernardoEm quarta-feira, 11 de janeiro de 2023 09:39:17 GMT+1, Markus Neteler escreveu: Hi Bernardo, Not sure if this helps but there is also this function in r.mapcalc: https://grass.osgeo.org/grass78/manuals/r.mapcalc.html graph(x,x1,y1[x2,y2..]) convert the x to a y based on points in a graph F graph2(x,x1[,x2,..],y1[,y2..]) alternative form of graph() The graph() function allows users to specify a x-y conversion using pairs of x,y coordinates. In some situations a transformation from one value to another is not easily established mathematically, but can be represented by a 2-D graph and then linearly interpolated. The graph() function provides the opportunity to accomplish this. An x-axis value is provided to the graph function along with the associated graph represented by a series of x,y pairs. The x values must be monotonically increasing (each larger than or equal to the previous). The graph function linearly interpolates between pairs. Any x value lower the lowest x value (i.e. first) will have the associated y value returned. Any x value higher than the last will similarly have the associated y value returned. [...] Perhaps a dynamic (set of) graphs could be constructed? Best, Markus On Wed, Dec 14, 2022 at 2:37 PM Bernardo Santos via grass-user wrote: > > Hi, > > I am trying to produce scenarios of past land cover, before hydropower > reservoirs were built. To do so, I need to fill empty pixels from a raster in > the locations where the reservoirs are currently present, using as input the > actual land cover map. I tried doing that with r.neighbors (taking > method=mode) with neighborhoods of increasing size, to replace null pixels > with the most common land cover class in the neighborhood. I also tried that > with r.fill.stats which is basically the same thing. > However, the results gets very homogeneous, since the interpolated null cells > always get the value of the most common land cover class. > > Do anyway know of a method in GRASS to perform a "probabilistic" > neirighborhood analysis, where cells in a neighborhood are given weights > (possibly related to the distance to the central cell and to their frequency) > and these weights are used to stocastically sample a value to fill the > central cell? > If not in GRASS, does anyway know of such a method in a different platform, > i.e. R? > > Thanks! > Best > Bernardo > ___ > grass-user mailing list > grass-user@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-user -- Markus Neteler, PhD https://www.mundialis.de - free data with free software https://grass.osgeo.org https://courses.neteler.org/blog ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Probabilistic neighborhood analysis
Hi Bernardo, Not sure if this helps but there is also this function in r.mapcalc: https://grass.osgeo.org/grass78/manuals/r.mapcalc.html graph(x,x1,y1[x2,y2..]) convert the x to a y based on points in a graph F graph2(x,x1[,x2,..],y1[,y2..]) alternative form of graph() The graph() function allows users to specify a x-y conversion using pairs of x,y coordinates. In some situations a transformation from one value to another is not easily established mathematically, but can be represented by a 2-D graph and then linearly interpolated. The graph() function provides the opportunity to accomplish this. An x-axis value is provided to the graph function along with the associated graph represented by a series of x,y pairs. The x values must be monotonically increasing (each larger than or equal to the previous). The graph function linearly interpolates between pairs. Any x value lower the lowest x value (i.e. first) will have the associated y value returned. Any x value higher than the last will similarly have the associated y value returned. [...] Perhaps a dynamic (set of) graphs could be constructed? Best, Markus On Wed, Dec 14, 2022 at 2:37 PM Bernardo Santos via grass-user wrote: > > Hi, > > I am trying to produce scenarios of past land cover, before hydropower > reservoirs were built. To do so, I need to fill empty pixels from a raster in > the locations where the reservoirs are currently present, using as input the > actual land cover map. I tried doing that with r.neighbors (taking > method=mode) with neighborhoods of increasing size, to replace null pixels > with the most common land cover class in the neighborhood. I also tried that > with r.fill.stats which is basically the same thing. > However, the results gets very homogeneous, since the interpolated null cells > always get the value of the most common land cover class. > > Do anyway know of a method in GRASS to perform a "probabilistic" > neirighborhood analysis, where cells in a neighborhood are given weights > (possibly related to the distance to the central cell and to their frequency) > and these weights are used to stocastically sample a value to fill the > central cell? > If not in GRASS, does anyway know of such a method in a different platform, > i.e. R? > > Thanks! > Best > Bernardo > ___ > grass-user mailing list > grass-user@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-user -- Markus Neteler, PhD https://www.mundialis.de - free data with free software https://grass.osgeo.org https://courses.neteler.org/blog ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Probabilistic neighborhood analysis
10 janv. 2023 08:46:42 Maris Nartiss : > Hello Bernardo, > although a solution with r.mapcalc random could be made to work, I'd > say creating a new dedicated module is the way to go. Just an idea – > create neighbour count raster (how many cells with centre class are in > a sliding window), in second pass unroll classes based on their count > and then choose random class from obtained list. > > I don't think it is so common to infill (inpaint) categorical values > in classification results of remote sensing. I think this is quite common. However, it is generally done using majority rules or similar. I don't think I have seen much use of randomization in that context. Moritz ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Probabilistic neighborhood analysis
Hello Bernardo, although a solution with r.mapcalc random could be made to work, I'd say creating a new dedicated module is the way to go. Just an idea – create neighbour count raster (how many cells with centre class are in a sliding window), in second pass unroll classes based on their count and then choose random class from obtained list. I don't think it is so common to infill (inpaint) categorical values in classification results of remote sensing. Māris. pirmd., 2023. g. 9. janv., plkst. 13:18 — lietotājs Bernardo Santos via grass-user () rakstīja: > > Hi Ken, > > The fuzzy logic tools seem interesting! But I am new to the concept so I did > not really think about how could I set functions/rules that increase with the > frequency of a land cover class... > Do you know any example in this context? > > I thought that people working with satellite imagery classification and cloud > cover would have experience with that, since sometimes it is necessary to > somehow interpolate and fill values cover by clouds... > > Best > B > > Em segunda-feira, 26 de dezembro de 2022 16:50:42 GMT+1, Ken Mankoff > escreveu: > > > What about using the fuzzy logic modules? > > -k. > > Please excuse brevity. Sent from tiny pocket computer with non-haptic > feedback keyboard. > > On Wed, Dec 14, 2022, 13:38 Bernardo Santos via grass-user > wrote: > > Hi, > > I am trying to produce scenarios of past land cover, before hydropower > reservoirs were built. To do so, I need to fill empty pixels from a raster in > the locations where the reservoirs are currently present, using as input the > actual land cover map. I tried doing that with r.neighbors (taking > method=mode) with neighborhoods of increasing size, to replace null pixels > with the most common land cover class in the neighborhood. I also tried that > with r.fill.stats which is basically the same thing. > However, the results gets very homogeneous, since the interpolated null cells > always get the value of the most common land cover class. > > Do anyway know of a method in GRASS to perform a "probabilistic" > neirighborhood analysis, where cells in a neighborhood are given weights > (possibly related to the distance to the central cell and to their frequency) > and these weights are used to stocastically sample a value to fill the > central cell? > If not in GRASS, does anyway know of such a method in a different platform, > i.e. R? > > Thanks! > Best > Bernardo > ___ > grass-user mailing list > grass-user@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-user > > ___ > grass-user mailing list > grass-user@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-user ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Probabilistic neighborhood analysis
Hi Ken, The fuzzy logic tools seem interesting! But I am new to the concept so I did not really think about how could I set functions/rules that increase with the frequency of a land cover class...Do you know any example in this context? I thought that people working with satellite imagery classification and cloud cover would have experience with that, since sometimes it is necessary to somehow interpolate and fill values cover by clouds... BestB Em segunda-feira, 26 de dezembro de 2022 16:50:42 GMT+1, Ken Mankoff escreveu: What about using the fuzzy logic modules? -k. Please excuse brevity. Sent from tiny pocket computer with non-haptic feedback keyboard. On Wed, Dec 14, 2022, 13:38 Bernardo Santos via grass-user wrote: Hi, I am trying to produce scenarios of past land cover, before hydropower reservoirs were built. To do so, I need to fill empty pixels from a raster in the locations where the reservoirs are currently present, using as input the actual land cover map. I tried doing that with r.neighbors (taking method=mode) with neighborhoods of increasing size, to replace null pixels with the most common land cover class in the neighborhood. I also tried that with r.fill.stats which is basically the same thing.However, the results gets very homogeneous, since the interpolated null cells always get the value of the most common land cover class. Do anyway know of a method in GRASS to perform a "probabilistic" neirighborhood analysis, where cells in a neighborhood are given weights (possibly related to the distance to the central cell and to their frequency) and these weights are used to stocastically sample a value to fill the central cell?If not in GRASS, does anyway know of such a method in a different platform, i.e. R? Thanks!BestBernardo___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Probabilistic neighborhood analysis
Hi Vero, Thanks for the suggestion.I tried it, but it only gives different weights to the values within the neighborhood according to a distance decay function. However, the values are still determined "deterministically". What I could do is to use the function terra::focal() in R, since within it I can define a function to be computed for the neighborhood and use sample() to make this operation probabilistic. It seems to work, but it quite time consuming though. BestBernardo Em segunda-feira, 26 de dezembro de 2022 16:13:02 GMT+1, Veronica Andreo escreveu: Hello Bernardo, I haven't tested myself, but have you tried r.neighbors with the different weight-related options? Vero El mié, 14 dic 2022 a las 10:38, Bernardo Santos via grass-user () escribió: Hi, I am trying to produce scenarios of past land cover, before hydropower reservoirs were built. To do so, I need to fill empty pixels from a raster in the locations where the reservoirs are currently present, using as input the actual land cover map. I tried doing that with r.neighbors (taking method=mode) with neighborhoods of increasing size, to replace null pixels with the most common land cover class in the neighborhood. I also tried that with r.fill.stats which is basically the same thing.However, the results gets very homogeneous, since the interpolated null cells always get the value of the most common land cover class. Do anyway know of a method in GRASS to perform a "probabilistic" neirighborhood analysis, where cells in a neighborhood are given weights (possibly related to the distance to the central cell and to their frequency) and these weights are used to stocastically sample a value to fill the central cell?If not in GRASS, does anyway know of such a method in a different platform, i.e. R? Thanks!BestBernardo___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Probabilistic neighborhood analysis
What about using the fuzzy logic modules? -k. Please excuse brevity. Sent from tiny pocket computer with non-haptic feedback keyboard. On Wed, Dec 14, 2022, 13:38 Bernardo Santos via grass-user < grass-user@lists.osgeo.org> wrote: > Hi, > > I am trying to produce scenarios of past land cover, before hydropower > reservoirs were built. To do so, I need to fill empty pixels from a raster > in the locations where the reservoirs are currently present, using as input > the actual land cover map. I tried doing that with r.neighbors (taking > method=mode) with neighborhoods of increasing size, to replace null pixels > with the most common land cover class in the neighborhood. I also tried > that with r.fill.stats which is basically the same thing. > However, the results gets very homogeneous, since the interpolated null > cells always get the value of the most common land cover class. > > Do anyway know of a method in GRASS to perform a "probabilistic" > neirighborhood analysis, where cells in a neighborhood are given weights > (possibly related to the distance to the central cell and to their > frequency) and these weights are used to stocastically sample a value to > fill the central cell? > If not in GRASS, does anyway know of such a method in a different > platform, i.e. R? > > Thanks! > Best > Bernardo > ___ > grass-user mailing list > grass-user@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-user > ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Probabilistic neighborhood analysis
Hello Bernardo, I haven't tested myself, but have you tried r.neighbors with the different weight-related options? Vero El mié, 14 dic 2022 a las 10:38, Bernardo Santos via grass-user (< grass-user@lists.osgeo.org>) escribió: > Hi, > > I am trying to produce scenarios of past land cover, before hydropower > reservoirs were built. To do so, I need to fill empty pixels from a raster > in the locations where the reservoirs are currently present, using as input > the actual land cover map. I tried doing that with r.neighbors (taking > method=mode) with neighborhoods of increasing size, to replace null pixels > with the most common land cover class in the neighborhood. I also tried > that with r.fill.stats which is basically the same thing. > However, the results gets very homogeneous, since the interpolated null > cells always get the value of the most common land cover class. > > Do anyway know of a method in GRASS to perform a "probabilistic" > neirighborhood analysis, where cells in a neighborhood are given weights > (possibly related to the distance to the central cell and to their > frequency) and these weights are used to stocastically sample a value to > fill the central cell? > If not in GRASS, does anyway know of such a method in a different > platform, i.e. R? > > Thanks! > Best > Bernardo > ___ > grass-user mailing list > grass-user@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-user > ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Probabilistic neighborhood analysis
Hi, I am trying to produce scenarios of past land cover, before hydropower reservoirs were built. To do so, I need to fill empty pixels from a raster in the locations where the reservoirs are currently present, using as input the actual land cover map. I tried doing that with r.neighbors (taking method=mode) with neighborhoods of increasing size, to replace null pixels with the most common land cover class in the neighborhood. I also tried that with r.fill.stats which is basically the same thing.However, the results gets very homogeneous, since the interpolated null cells always get the value of the most common land cover class. Do anyway know of a method in GRASS to perform a "probabilistic" neirighborhood analysis, where cells in a neighborhood are given weights (possibly related to the distance to the central cell and to their frequency) and these weights are used to stocastically sample a value to fill the central cell?If not in GRASS, does anyway know of such a method in a different platform, i.e. R? Thanks!BestBernardo___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
