Felipe Barriga Richards » GIS http://blog.felipebarriga.cl Blog personal de Felipe Barriga Richards Thu, 29 Dec 2011 17:15:50 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 OLHeatmap (OpenLayers Heatmap) http://blog.felipebarriga.cl/programacion/olheatmap-openlayers-heatmap/ http://blog.felipebarriga.cl/programacion/olheatmap-openlayers-heatmap/#comments Sat, 31 Jul 2010 18:54:42 +0000 fbarriga http://blog.felipebarriga.cl/?p=496 After some time thinking I’ve decided to release the source code of OLHeatmap as GPLv2 to incentive others developers to join and help in the project.
Here is the original post showing OLHeatmap working and here is the project link in SourceForge (the guys at savannah.gnu.org take too long to approve a project…): http://olheatmap.sourceforge.net

]]> http://blog.felipebarriga.cl/programacion/olheatmap-openlayers-heatmap/feed/ 0 OpenStreetMap Heatmap (using OpenLayers) http://blog.felipebarriga.cl/programacion/openstreetmap-heatmap-using-openlayers/ http://blog.felipebarriga.cl/programacion/openstreetmap-heatmap-using-openlayers/#comments Mon, 17 May 2010 06:04:23 +0000 fbarriga http://blog.felipebarriga.cl/?p=362 After been working sometime with OpenLayers I figure out how to make heatmaps generated in the user browser. Now I’m using OpenStreetMap for both map and data. As is based on OpenLayers you can use any map (including Google Maps) and get data from other places.

There are some similar projects: gheat (server side), Google Maps – Heatmap (server side, not dynamic) and HeatMapAPI (server side and need an API key). If you know another API/Library to make Heatmaps please send me an email.

Currently you can watch the following demo videos (try to watch them on HD and fullscreen):


Videos




TODO

  • Add Heatmap auto-rendering option
  • Optimize Code
  • Improve compatibility with Chromium (Google Chrome)
  • Check compatibility with other browsers
  • Improve GUI
  • Make a Javascript Library
  • Use JSON instead of XML
  • Check security on server-side
  • Opacity of Features
  • Compatibility with polygons (currently only nodes)


Bugs

  • Features are rendered more than once (double, triple?)


Limitations

  • Don’t work on Microsoft Internet Explorer (maybe it’s a feature!)
]]> http://blog.felipebarriga.cl/programacion/openstreetmap-heatmap-using-openlayers/feed/ 9 Convert big PDF to huge image (maps) http://blog.felipebarriga.cl/otros/convert-big-pdf-to-huge-image-map/ http://blog.felipebarriga.cl/otros/convert-big-pdf-to-huge-image-map/#comments Wed, 14 Apr 2010 01:17:48 +0000 fbarriga http://blog.felipebarriga.cl/?p=305 To convert PDF to big images like maps you can try with Gimp but it eat too much memory and is a bit slow.
The other option is to use ImageMagick:

felipe@funstation $ convert file.pdf file.jpg

If the output image is to small you can try to change the pixel density (dpi) which is 72dpi by default to a bigger one.
Here is an example using 500dpi, 8 bits of color (256), inverting the colors (negate) and saving it in PNG format:

felipe@funstation $ convert -density 500 -negate -depth 8 base_actualizado_diciembre_2009.pdf base_actualizado_diciembre_2009-500-invert-8bits.png

The sample file is here: http://www.osornochile.cl/webimo/documentos/base_actualizado_diciembre_2009.pdf
The PDF size is 7.5M and the output PNG size is 59M.

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