On the road with R & Grass: Intervisibility along Lines

While drinking a glass of french Ricard (a famous drink from Provence) with Bertrand Bouteilles (see his blog) , a colleague of mine, the latter asked me if I knew a method to calculate the line-of-sight from a line. Usually, we calculate LOS from one XYZ observation points but I had not found any resource on the web for line.

[Feed #2] PostGIS 2.0, WPS Shoot-out, Spatial Analysis, GeOps or easy editing with OpenLayers,...

Spatial Analysis

Here is a very good and complete resource I found dealing with different aspects of spatial analysis.
>> http://www.spatialanalysisonline.com/output/

A scientific article about topological models and frameworks for 3D spatial objects
>> http://www.gdmc.nl/zlatanova/thesis/html/refer/ps/sdarticle.pdf

Softwares

Spatial Business Intelligence is gaining a lot of interest as more and more

Feed #1 foss4G, OpenAerialMap, QGIS & GvSIG,...

Events

- FOSS4G, a major event for the Open Source GIS World. A little review here
>> http://slashgeo.org/2011/09/15/FOSS4G-2011-OpenData-OpenLayers-Mobile-Nodejs-Mapnik-OpenAerialMap


- Web services, clouds...but no need to buy a plane to reach them...During FOSS4G, a nice application has been presented implementing WPS (Web Processing Service) through the implementation of ZOO API project. It gives an idea of the dynamics of web GIS applications development and the possibility of realizing some web apps that are similar to desktop ones
>> http://www.mapmint.com/index.php?page=mapmint-modules

[R] Buildings on Google Earth : from 2D to 3D

As I discover the marvels of (geo)R world, I found out this article (link)

It explains how to generate KML files from meuse, the source dataset delivered with sp package, using R software.

In the tutorial, KML files are created from scracth, writing each line of it.OGR driver only gives access to the options name and description (rdgal driver). So, "brute coding" may be necessary if you want to control other elements: color, heights for extruded objects...

Many people would like to visualize some buildings in 3D in google. The reference data that we have for buildings is often plain but there usually is a column specifying the height of each building. For example, for the french BDTOPO, the HAUTEUR column.

[Rasters in QGIS] Generate a Vector Grid with Average Slope Values

Operations:

• Slope: DEM Layer.tif=[QGIS/Raster Based Terrain Analysis]=>slope.tif=>[r.in.gdal]=>slope
• Grid: [QGIS/Vector/Research Tools/Vector Grid]=>grid.shp=[v.in.ogr]=>grid=>[v.to.rast]=>grid
• Crossing Grid and Slope: grid*slope=[r.average]=>gridSlope=[r.to.vect]=>gridSlope=[v.out.ogr]=>gridSlope.shp