Thomas Bonfort wrote: > Hi Jukka, > Thanks for the comments, which I mostly agree with. I should clearly > remove references to the the term of "interpolation" as it does not > apply to the proposed solution. Concerning the "heatmap" term that > should be replaced by "kernel density" that could be a possibility, > although as you said the "heatmap" term has become so common that I'd > suspect many users wouldn't give a "kernel density" solution a look even > if that is what they are after. > I'll rework the RFC to suppress the interpolation references, and use a > "connectiontype density", would that work for you?
Everybody calls them as heatmaps so let it be so but make a difference between density and interpolation. Connectiontype interpolation can be reserved for the future. >> I am not sure if this image generator can even make such heatmaps like the >> salinity map in the beginning of RFC where missing data between the >> measuring points are (linearly?) interpolated. In that map the density of >> salinity measurement stations has no effect on the colour. Also in real life >> even if you measure a hundred times a temperature of +40 degrees from very >> close measuring points, the maximum temperature does not rise a bit over +40. > correct, the proposed solution will be biased by samples close to one > another. >> The system itself is welcome and I am interested in seeing how the problem >> of creating automatically a good looking visualization for changing map >> scales is solved. Perhaps output pixel based interpolation radius and >> PROCESSING “NORMALIZATION=AUTO" will handle that. > I'm not sure I understand what you're looking for here, can you be a bit > more precise? I tried to say that same settings for radius and colorrange tend to work well only for a limited scale range. Here are two examples which are using the same traffic accidend data. http://www.hs.fi/kotimaa/Nettisivusto+paljastaa+Helsingin+vaarallisimmat+risteykset/a1305551700052 This one overrates accidents at small scale and burns everything red. When you zoom in the accidents almost disappear and the hotspots are lost. http://cloudnsci.fi/wiki/demos/traffic_accidents_in_Helsinki_heatmap.html This one is static and looks good at medium scales but does not work well at big and small scales. I feel that the search radius and colorrange should be adjusted somehow by the scale but I can't suggest how. But perhaps it can be done rather easily with a few scale dependent classes. -Jukka Rahkonen- -- thomas > > -Jukka Rahkonen- > > ________________________________________ > Thomas Bonfort wrote: > >> Devs, > >> please have a look at RFC-108 [1]. The associated code and the RFC are >> still beta, so there's still plenty of room for modification or remarks. > >> best regards, > thomas > > [1] http://mapserver.org/development/rfc/ms-rfc-108.html > _______________________________________________ > mapserver-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/mapserver-dev > _______________________________________________ > mapserver-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/mapserver-dev > _______________________________________________ mapserver-users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/mapserver-users _______________________________________________ mapserver-users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/mapserver-users
