Re: [R] Natural colours for topographic data
Tysdag 24. november 2009 11.08.08 skreiv du: I would be happy with a simple one, that just mapped negative values to water colours and positive values to land colours. Have you tried my colourscheme package? Its not on CRAN but you can get it from here: Thanks for the suggestion. It looks very nice. Perhaps I’ll even write a general function for generating topographic colour scales, based on this. (It might be a while before it’s ready, though.) -- Karl Ove Hufthammer http://huftis.org/ Jabber: k...@huftis.org __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Natural colours for topographic data
On Mon, 23 Nov 2009 12:21:03 -0500 David Winsemius dwinsem...@comcast.net wrote: I would be happy with a simple one, that just mapped negative values to water colours and positive values to land colours. Searching with the strategy color positive negative zero in r-search and limiting it to r-help replies, I get this Jim Lemon reply using (naturally) plotrix's color.scale: http://finzi.psych.upenn.edu/R/Rhelp02/archive/90837.html The application to your needs looks pretty immediate. Thanks for the suggestion, but the arguments that 'color.scale' takes (range of red, green and blue values) makes it not very useful for this purpose. -- Karl Ove Hufthammer __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Natural colours for topographic data
On Tue, Nov 24, 2009 at 8:42 AM, Karl Ove Hufthammer k...@huftis.org wrote: On Mon, 23 Nov 2009 12:21:03 -0500 David Winsemius dwinsem...@comcast.net wrote: I would be happy with a simple one, that just mapped negative values to water colours and positive values to land colours. Searching with the strategy color positive negative zero in r-search and limiting it to r-help replies, I get this Jim Lemon reply using (naturally) plotrix's color.scale: http://finzi.psych.upenn.edu/R/Rhelp02/archive/90837.html The application to your needs looks pretty immediate. Thanks for the suggestion, but the arguments that 'color.scale' takes (range of red, green and blue values) makes it not very useful for this purpose. Have you tried my colourscheme package? Its not on CRAN but you can get it from here: http://r-forge.r-project.org/projects/colourscheme/ And can be installed thus: install.packages(colourschemes,repos=http://r-forge.r-project.org;) [sorry about the inconsistency between 'colourscheme' and 'colourschemes'!] Vignette via r-forge's source code browser: http://r-forge.r-project.org/plugins/scmsvn/viewcvs.php/*checkout*/pkg/inst/doc/colourschemes.pdf?rev=19root=colourscheme It defines various ways of mapping values to colours and using those colours in plots. I use topographic-style colour schemes in the examples, so this might be just what you want. The example in ?multiRamp is this: # topological colour scheme - water, land, ice: tramp = multiRamp(rbind(c(-2000,0),c(0,1000),c(1000,9000)), list(c(black,blue),c(green,brown),c(gray70,gray70)) ) then: tramp(-100) [1] #F2FF - is a colour between black and blue in the ocean tramp(500) [1] #539515FF - is somewhere between green and brown in the land tramp(1500) [1] #B3B3B3FF - is the gray of the ice. No logarithmic colour scaling, but I do detail in the vignette how to write your own colour scheme functions that are compatible with the ones supplied. Will be glad to help more on this! Barry __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Natural colours for topographic data
On 11/24/2009 07:42 PM, Karl Ove Hufthammer wrote: On Mon, 23 Nov 2009 12:21:03 -0500 David Winsemius dwinsem...@comcast.net wrote: I would be happy with a simple one, that just mapped negative values to water colours and positive values to land colours. Searching with the strategy color positive negative zero in r-search and limiting it to r-help replies, I get this Jim Lemon reply using (naturally) plotrix's color.scale: http://finzi.psych.upenn.edu/R/Rhelp02/archive/90837.html The application to your needs looks pretty immediate. Thanks for the suggestion, but the arguments that 'color.scale' takes (range of red, green and blue values) makes it not very useful for this purpose. Hi Karl, For a start, you could try: color.scale(oceandepths,extremes=c(lightblue,blue)) for the water and color.scale(vegetationcover,c(0.55,0),0.55,0) for the land as really basic natural colors. There are several ways to specify the value to color transformations, and you can even overwrite some parts of the color matrix using logical vectors, like coloring everything over 4000 meters white for snow. Jim __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] Natural colours for topographic data
Dear list members I'm currently working on some topographic (elevation) data, and was somewhat surprised that the 'topo.colors' and 'terrain.colors' are of little to no use here. The problem is that these functions only return a palette of colours; they don't map depth values to colours. So if I plot (using 'image', 'persp' or similar functions) and specify these palettes, ocean areas may coloured green (indicating) land, which may be quite confusing. I have looked through various packages, and have found several colour palette functions, but none that do what I need. Basically, I just need a function that takes a vector of elevation values as input, and outputs a vector of 'natural' colours. For negative values (i.e., ocean), the 'blue' colours of 'topo.colors' would be OK, and for positive values either the colours of 'terrain.colors' or the non-blue colours of 'topo.colors' would look nice. It is of course not very difficult to create such a function myself, e.g. using the 'cut' function and a standard palette. But perhaps somebody has already has made one? My ideal topographic colour mapping function would support separate colour levels for water and land (so that you can specifiy for example 5 colours of water, from a depth of 5000 meters to 0 meters, and 20 colours of land, from a depth of 0 meters to 2000 meters), support several nice palettes, and also support logarithmic colour mapping. But I would be happy with a simple one, that just mapped negative values to water colours and positive values to land colours. -- Karl Ove Hufthammer __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Natural colours for topographic data
On Nov 23, 2009, at 11:52 AM, Karl Ove Hufthammer wrote: Dear list members I'm currently working on some topographic (elevation) data, and was somewhat surprised that the 'topo.colors' and 'terrain.colors' are of little to no use here. The problem is that these functions only return a palette of colours; they don't map depth values to colours. So if I plot (using 'image', 'persp' or similar functions) and specify these palettes, ocean areas may coloured green (indicating) land, which may be quite confusing. I have looked through various packages, and have found several colour palette functions, but none that do what I need. Basically, I just need a function that takes a vector of elevation values as input, and outputs a vector of 'natural' colours. For negative values (i.e., ocean), the 'blue' colours of 'topo.colors' would be OK, and for positive values either the colours of 'terrain.colors' or the non-blue colours of 'topo.colors' would look nice. It is of course not very difficult to create such a function myself, e.g. using the 'cut' function and a standard palette. But perhaps somebody has already has made one? My ideal topographic colour mapping function would support separate colour levels for water and land (so that you can specifiy for example 5 colours of water, from a depth of 5000 meters to 0 meters, and 20 colours of land, from a depth of 0 meters to 2000 meters), support several nice palettes, and also support logarithmic colour mapping. But I would be happy with a simple one, that just mapped negative values to water colours and positive values to land colours. Searching with the strategy color positive negative zero in r-search and limiting it to r-help replies, I get this Jim Lemon reply using (naturally) plotrix's color.scale: http://finzi.psych.upenn.edu/R/Rhelp02/archive/90837.html The application to your needs looks pretty immediate. -- Karl Ove Hufthammer __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. David Winsemius, MD Heritage Laboratories West Hartford, CT __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
