Superimpose grid ad shape file

[Etienne DELAY]

Dear all, 

I would like load shape file and and a grid in tif. Both of them are in WGS84 (EPSG 4326). When I load it in Gama the projection doesn't work ...

Where I'm wrong ?

global{ //Declare the world as a torus or not torus environment

//Shapefile of country

file country_shapefile <- file("../includes/world_shape/europ_migration.shp");

// Raster

file dem_file <- file("../includes/dem/dem_resemple50.tif") ;

init{

create country from: country_shapefile;

create events from: event_shapefile with: [ev_type::string(read("event"))];

}

}

species country {

aspect default {

draw shape color: nil border: #black;

}

}

//Grid species representing a cellular automata

grid dem_cell file:dem_file {

float elevation ;

init{

if(grid_value > 0){

elevation <- grid_value;

}

}

rgb pcolor <- blend(#black,#white, elevation);

aspect col_elevation{

draw shape color:pcolor border:#black empty:false;

}

}

xperiment courlisabstract type: gui {

/** Insert here the definition of the input and output of the model */

output {

display sp_display type: opengl{

grid dem_cell ;

species dem_cell aspect: col_elevation;

species country refresh: false;

}

}

}

E.

[Patrick Taillandier]

Hi,

You have to define the size of the world from the tiff file: in the global section :

geometry shape <- envelope(dem_file);

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[Etienne DELAY]

Re, 

Done thank you !

E.

[Etienne DELAY]

Arg, 

In fact ... non better but not well superimposed :-S

E.

[Patrick Taillandier]

Ok, it is maybe because GAMA has some difficulties when projecting grids: indeed, GAMA only works with projected CRS, so when you are using non projected one (typically WGS84), GAMA tries to project it with a UTM projection.... but the way the grids are managed in GAMA could have an impact on the resulting geometries after projection. Can you try to change the CRS of the tiff file to a projected one (UTM for instance) with QGIS, and test with this projected grid in GAMA?

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[Etienne DELAY]

Need I project grid and shape(s) in UTM ?

[Patrick Taillandier]

just the grid should be enough

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[Etienne DELAY]

Which UTM  epsg do you counsel for project European stuff?

[Patrick Taillandier]

Maybe, for Europe, you should rather use a CRS like ETRS89 / ETRS-LCC :  (http://spatialreference.org/ref/epsg/etrs89-etrs-lcc/)

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[Etienne DELAY]

Perfect !