The present model will introduce how to design a road system, or graph, based on the road GIS data and provide each edge a weightrepresenting the destruction level of the road.
* destruction_coeff”.We add a destruction_coeff variable which initial value is randomly defined between 1 and 2 and that have a max of 2. The color of the agent will depend of this variable. In order to simplify the GAML code, we define a new variable colorValue that represents the value of red color and that will be defined between 0 and 255.
species road {
float destruction_coeff <- 1 + ((rnd(100))/ 100.0) max: 2.0;
int colorValue <- int(255*(destruction_coeff - 1)) update: int(255*(destruction_coeff - 1));
rgb color <- rgb(min([255, colorValue]),max ([0, 255 - colorValue]),0) update: rgb(min([255, colorValue]),max ([0, 255 - colorValue]),0) ;
...
}
In GAMA, adding a weight for a graph is very simple, we use the as_edge_graph operator with the graph for left-operand and a weight map for the right-operand. A weight contains the weight of each edge: [edge1::weight1, edge2:: weight2,…]. In this model, the weight will be equal to the length of the road (perimeter of the polyline) **its destruction coefficient.
init {
...
create road from: shape_file_roads ;
map<road,float> weights_map <- road as_map (each:: (each.destruction_coeff * each.shape.perimeter));
the_graph <- as_edge_graph(road) with_weights weights_map;
...
}
```**
## Complete Model
model tutorial_gis_city_traffic
global { file shape_file_buildings <- file(“../includes/building.shp”); 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; int nb_people <- 100; int current_hour update: (time / #hour) mod 24; int min_work_start <- 6; int max_work_start <- 8; int min_work_end <- 16; int max_work_end <- 20; float min_speed <- 1.0 #km / #h; float max_speed <- 5.0 #km / #h; graph the_graph;
init {
create building from: shape_file_buildings with: [type::string(read ("NATURE"))] {
if type="Industrial" {
color <- #blue ;
}
}
create road from: shape_file_roads ;
map<road,float> weights_map <- road as_map (each:: (each.destruction_coeff * each.shape.perimeter));
the_graph <- as_edge_graph(road) with_weights weights_map;
list<building> residential_buildings <- building where (each.type="Residential");
list<building> industrial_buildings <- building where (each.type="Industrial") ;
create people number: nb_people {
speed <- min_speed + rnd (max_speed - min_speed) ;
start_work <- min_work_start + rnd (max_work_start - min_work_start) ;
end_work <- min_work_end + rnd (max_work_end - min_work_end) ;
living_place <- one_of(residential_buildings) ;
working_place <- one_of(industrial_buildings) ;
objective <- "resting";
location <- any_location_in (living_place);
}
} }
species building { string type; rgb color <- #gray ;
aspect base {
draw shape color: color ;
} }
species road { float destruction_coeff <- 1 + ((rnd(100))/ 100.0) max: 2.0; int colorValue <- int(255(destruction_coeff - 1)) update: int(255(destruction_coeff - 1)); rgb color <- rgb(min([255, colorValue]),max ([0, 255 - colorValue]),0) update: rgb(min([255, colorValue]),max ([0, 255 - colorValue]),0) ;
aspect base {
draw shape color: color ;
} }
species people skills:[moving] { rgb color <- #yellow ; building living_place <- nil ; building working_place <- nil ; int start_work ; int end_work ; string objective ; point the_target <- nil ;
reflex time_to_work when: current_hour = start_work and objective = "resting"{
objective <- "working" ;
the_target <- any_location_in (working_place);
}
reflex time_to_go_home when: current_hour = end_work and objective = "working"{
objective <- "resting" ;
the_target <- any_location_in (living_place);
}
reflex move when: the_target != nil {
do goto target: the_target on: the_graph ;
if the_target = location {
the_target <- nil ;
}
}
aspect base {
draw circle(10) color: color;
} }
experiment road_traffic type: gui { parameter “Shapefile for the buildings:” var: shape_file_buildings category: “GIS” ; parameter “Shapefile for the roads:” var: shape_file_roads category: “GIS” ; parameter “Shapefile for the bounds:” var: shape_file_bounds category: “GIS” ; parameter “Number of people agents” var: nb_people category: “People” ; parameter “Earliest hour to start work” var: min_work_start category: “People” min: 2 max: 8; parameter “Latest hour to start work” var: max_work_start category: “People” min: 8 max: 12; parameter “Earliest hour to end work” var: min_work_end category: “People” min: 12 max: 16; parameter “Latest hour to end work” var: max_work_end category: “People” min: 16 max: 23; parameter “minimal speed” var: min_speed category: “People” min: 0.1 #km/#h ; parameter “maximal speed” var: max_speed category: “People” max: 10 #km/#h;
output {
display city_display type:opengl {
species building aspect: base ;
species road aspect: base ;
species people aspect: base ;
}
} } ```