Graphe non connexe

[Damien Philippon]

Hi everyone,

I have to ask something about graph, and even after looking in the documentation about it, I didn't find any answer. 

Is there any operator which allows the build of a non related graph but which got related components by providing

a shapefile ?

Thanks a lot,

Damien

[Benoit Gaudou]

Hi Damien,

I am wondering: if roads in a shapefile are not all connected, you get a graph with several components. That is what you want right ? 

Benoit 

2015-11-15 14:26 GMT+01:00 Damien Philippon <nijige...@gmail.com>:

Bonjour à tous,

J'ai une question, j'ai cherché dans la doc et rien n'est écrit à ce sujet. 

Y a t'il un opérateur qui permet de concevoir des graphes non connexes mais avec

des composantes connexes en fournissant un shapefile ?

Merci beaucoup,

Damien

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[Damien Philippon]

Hi Benoit,

yes this is exactly what i want, but in Gama, it loads only a big connected component and all others aren't loaded. 

Thank you for your answer !

Damien

[Benoit Gaudou]

Hi 

I am surprised ...

I had a lot of problems in my models because the roads were not well connected so, car cannot go from one graph to the other.

I tried with the following shapefile (road classical shapefile), but I cut the graph.

When I import data and create the graph, it seems that all roads are in the graph, even if they are not in the same component : 

model tutorial_gis_city_traffic

global {

file shape_file_roads <- file("../includes/road.shp");

file shape_file_bounds <- file("../includes/bounds.shp");

geometry shape <- envelope(shape_file_bounds);

float step <- 10 #mn;

graph the_graph;

init {

create road from: shape_file_roads ;

the_graph <- as_edge_graph(road);

write the_graph;

}

}

species road  {

rgb color <- #black ;

aspect base {

draw shape color: color ;

}

}

experiment road_traffic type: gui {

parameter "Shapefile for the roads:" var: shape_file_roads category: "GIS" ;

parameter "Shapefile for the bounds:" var: shape_file_bounds category: "GIS" ;

output {

display city_display type:opengl {

species road aspect: base ;

}

}

}

[Damien Philippon]

Ok, I'm surprised too because it works !

After trying to better understand, it looks like one of the shapefiles of QGIS wasn't refreshed ...

I opened the attributes tables and things were there but not shown in GAMA.. So I created

new shapefiles with the same data, new workspace in GAMA and now it's fine, I don't have

an empty graph. 

In any case, thank you very much !

Damien

[HUYNH Nghi]

Hi Damien,

When i work with Mai, i have counter some problem with graph data  (merge road, cut road, switch form qgis to gama, gama to qgis...). You can found my model which i use to test the number components of a graph (graph connected will have only 1 component). The colors will show that every two the roads are connected (same color) or dispatch (two color).

HUYNH Nghi

[Vietnam] +84909128322
GAMA http://www.gama-platform.org/

[Damien Philippon]

Hi Nghi, 

Thank you for your answer, I find your algorithm really interesting and I'll use it to debug my model.

Thank both of you again !

Damien