[Qgis-user] Organic heatmap outter contour, and making it look better

[Brent Wood]

Generic Mapping Tools (http://gmt.soest.hawaii.edu) can do all you want, fully scripted:
surface, triangulate, xyz2grd, greenspline can all generate a grid from scattered point data, depending just how you want it done
gridhisteq can normalise it if requiredgrdimage will turn it into a postscript imageps2raster will turn it into a georeferenced png
if you want to clip it to a contour, you can use psclip, or you can use a colour palette to set cells representing certain values to NA, & render them as transparent 

you can then provide it as a WMS layer with mapserver, qgis server or geoserver 
See sections 7.14-7.19 here:http://gmt.soest.hawaii.edu/gmt4/gmt/html/GMT_Docs.html

GDAL may be adequate, but has a more limited set of gridding & cartographic tools, and GRASS can also do what you want.

      From: Marcelo de Moraes Serpa <celoserpa at gmail.com>
 To: qgis-user <qgis-user at lists.osgeo.org> 
 Sent: Saturday, July 25, 2015 3:13 PM
 Subject: Re: [Qgis-user] Organic heatmap outter contour, and making it look better
   
Ops, forgot to include the reference heatmaps here. The goal is to get it to look +- like the ones below:
* http://www.gislounge.com/wp-content/uploads/2014/08/fortune1000-heat-kernel-us.png
and/or* http://i.stack.imgur.com/DvVyU.png
Cheers,
-- Marcleo.


On Fri, Jul 24, 2015 at 9:58 PM, Marcelo de Moraes Serpa <celoserpa at gmail.com> wrote:

Thanks to @Neumann, @Abdishakur and @Richard from my previous thread, the info was valuable! I did reply the post with some additional questions it but for some reason the mailing list server bounced my messages. They are not so relevant anymore, but if you get them, I'd still want to know your opinions.
Anyway, I played a couple of hours today with the data I have and with the interpolation and countours features of QGis (which seems to use Gdal under the cover, which was, for me, a quite interesting finding! That means that any result I get with QGis could easily be scriptable, which is  a must, since it will eventually be used in a web app pipeline) and I got this: 
https://www.dropbox.com/s/9ig76n1kcxoo76w/Screenshot%202015-07-24%2021.39.00.png?dl=0

It still doesn't look quite like I want*[0] but I'm getting there. The countours feature seems to be what I want. The numbers, by the way, is revenue per day in a certain area. The colors are not quite right (too many of them) so I need to tweak the styles, I think, and I don't want the actual countours lines to appear. They all seem to be simple problems to solve, but if you know how to do them, I'd love to know!
What seems to be more complicated, is how to create an organic feeling to the map. I don't want it to be a square, like this, I want the edge to follow the outter points. Here's what I mean: https://www.dropbox.com/s/k6na766a4ox1ngg/Screenshot-2015-07-15-21.47.55.jpg?dl=0. Does anyone have any idea of to do this?
Thanks!
-- Marcelo.




_______________________________________________
Qgis-user mailing list
Qgis-user at lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20150726/be90639d/attachment.html>