The Save Statement
Allows to save data in a file. The type of file can be "shp", "text" or "csv". The
save statement can be use in an init block, a reflex, an action or in a user command. Do not use it in experiments.
to(string): an expression that evaluates to an string, the path to the file
data(any type), (omissible) : any expression, that will be saved in the file
crs(any type): the name of the projectsion, e.g. crs:"EPSG:4326" or its EPSG id, e.g. crs:4326. Here a list of the CRS codes (and EPSG id): http://spatialreference.org
rewrite(boolean): an expression that evaluates to a boolean, specifying whether the save will ecrase the file or append data at the end of it
type(an identifier): an expression that evaluates to an string, the type of the output file (it can be only "shp", "text" or "csv")
- Its simple syntax is:
save data to: output_file type: a_type_file;
- To save data in a text file:
save (string(cycle) + "->" + name + ":" + location) to: "save_data.txt" type: "text";
- To save the values of some attributes of the current agent in csv file:
save [name, location, host] to: "save_data.csv" type: "csv";
- To save the geometries of all the agents of a species into a shapefile (with optional attributes):
save species_of(self) to: "save_shapefile.shp" type: "shp" with: [name::"nameAgent", location::"locationAgent"] crs: "EPSG:4326";
Export files in experiment
Displays are not the only output you can manage in GAMA. Saving data to a file during an experiment can also be achieved in several ways, depending on the needs of the modeler. One way is provided by the
save statement, which can be used everywhere in a model or a species. The other way, described here, is to include an
output_file statement in the output section.
output_file name:"file_name" type:file_type data:data_to_write;
file_type: text, csv or xml
file name: "results" type: text data: time + "; " + nb_preys + ";" + nb_predators refresh:every(2);
Each time step (or according to the frequency defined in the
refresh facet of the file output), a new line will be added at the end of the file. If
rewrite: false is defined in its facets, a new file will be created for each simulation (identified by a timestamp in its name).
footer and a
header can also be described with the corresponding facets (of type string).
Image files can be exported also through the
autosave facet of the display, as explained in this previous part.