Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-19 Thread Karl Ove Hufthammer
Rolf Turner wrote: 'ppp' objects used by 'spatstat' have an annoying structure SNIP Annoyance is in the mind of the beholder I think. Personally I find the structure of ppp objects absolutely *delightful*! :-) Also, they are simple, intuitive, easy to work with, and easy to

Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-19 Thread Marcelino de la Cruz
Next time do not spend so much time looking for a window :-) ppp(x,y, xrange=range(x), yrange=range(y)) This is based on the extent / bounding box of the data. By the way, there is not *default* window, And I also find the structure of ppp objects definitely *delightful*! Cheers,

Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-19 Thread Barry Rowlingson
On Tue, Oct 19, 2010 at 11:58 AM, Karl Ove Hufthammer k...@huftis.org wrote: And though the ‘window’ element of ‘ppp’ objects may be of use to some people, I haven’t had any use for it. The annoying thing here is that the constructor doesn’t generate the window automatically, based on the

Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-19 Thread jeremy.raw
@stat.math.ethz.ch Subject: Re: [R-sig-Geo] Creating density heatmaps for geographical data On Tue, Oct 19, 2010 at 11:58 AM, Karl Ove Hufthammer k...@huftis.org wrote: And though the 'window' element of 'ppp' objects may be of use to some people, I haven't had any use for it. The annoying thing here

Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-19 Thread Rolf Turner
The spatstat package is designed for the analysis of spatial point patterns. In this context the existence of a window --- the *observation* window --- is absolutely crucial. You have to know where points have been *looked for*, because there is information in where the points aren't, as well

Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-19 Thread Roger Bivand
On Wed, 20 Oct 2010, Rolf Turner wrote: The spatstat package is designed for the analysis of spatial point patterns. In this context the existence of a window --- the *observation* window --- is absolutely crucial. You have to know where points have been *looked for*, because there is

Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-18 Thread Karl Ove Hufthammer
Michael Sumner wrote: Just answering your first question, you could call sm.density for each point individually, then trim back to whatever level you want. Sum each grid for each point and you might get a better trim. Otherwise, you'd need to hack the density functions in kde2d or

Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-18 Thread Rolf Turner
On 19/10/2010, at 12:43 AM, Karl Ove Hufthammer wrote: SNIP 'ppp' objects used by 'spatstat' have an annoying structure SNIP Annoyance is in the mind of the beholder I think. Personally I find the structure of ppp objects absolutely *delightful*! :-) Also, they are simple,

Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-14 Thread Karl Ove Hufthammer
Karl Ove Hufthammer wrote: However, since the ‘heatmap’ is really a density estimate, it integrates to 1. I would instead want the heatmap colours to correspond to real frequencies (of course, they do, but the actual mapping is not visible on the colour scale). I have been thinking a bit

Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-14 Thread Sean O'Riordain
Karl, Thank you for that - some interesting ideas there. While not a solution for you - I'm working on a similar problem and I've discovered mapserver(.org) for the display side of things. It will handle rasters and shape files and display them quickly on a google map background. It will also

Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-14 Thread Michael Sumner
Just answering your first question, you could call sm.density for each point individually, then trim back to whatever level you want. Sum each grid for each point and you might get a better trim. Otherwise, you'd need to hack the density functions in kde2d or sm.density, or maybe in KernSmooth to

Re: [R-sig-Geo] Creating density heatmaps for geographical data

2010-10-14 Thread Karl Ove Hufthammer
Sean O'Riordain wrote: Thank you for that - some interesting ideas there. While not a solution for you - I'm working on a similar problem and I've discovered mapserver(.org) for the display side of things. It will handle rasters and shape files and display them quickly on a google map

[R-sig-Geo] Creating density heatmaps for geographical data

2010-10-13 Thread Karl Ove Hufthammer
Dear list members, Does anybody have suggestions for the best way of creating density heatmaps for geographical data? With ‘density heatmaps’ I’m not thinking of heatmaps as in R’s ‘heatmap’ function, but more along the lines of http://www.heatmapapi.com/ or