androidjava
I'm building a location based android application with following requirements:
All the processing will be done on the server side. The android application will communicate with the server through web services. What tools and packages do I require to achieve these requirements? I'm new to GIS.
My preferences are java and free software.
Dont be complicated if you can be simple.
1) Client-side: pure jQuery and html. JSON + Ajax to communicate with server.
function loadCities() {
var mapbounds = map.getExtent();
mapbounds.transform(toProjection, fromProjection );
bbox = mapbounds.toArray();
var bleft = bbox[0];
var bbottom = bbox[1];
var bright = bbox[2];
var btop = bbox[3];
showLoader();
var origem = "getCities?bleft=" + bleft + "&bbottom=" + bbottom + "&bright=" + bright + "&btop=" + btop;
$.ajax({
url: origem,
dataType: "json"
}).always(function() { hideLoader(); }).done(function(data) {
data = eval( data );
var geojson_format = new OpenLayers.Format.GeoJSON({
'internalProjection': map.baseLayer.projection,
'externalProjection': new OpenLayers.Projection("EPSG:4326")
});
citiesLayer.removeAllFeatures();
citiesLayer.addFeatures(geojson_format.read(data));
});
}
2) Server side: Struts Actions configured to JSON responses:
@Action(value="getCities", results= {
@Result(name="ok", type="httpheader", params={"status", "200"}) }
)
@ParentPackage("default")
public class GetCitiesAction {
public String execute(){
HttpServletRequest request = (HttpServletRequest) ActionContext.getContext().get(StrutsStatics.HTTP_REQUEST);
Double bleft = Double.parseDouble( request.getParameter("bleft") );
Double bbottom = Double.parseDouble( request.getParameter("bbottom") );
Double bright = Double.parseDouble( request.getParameter("bright") );
Double btop = Double.parseDouble( request.getParameter("btop") );
int idUsuario = Integer.valueOf( request.getParameter("idUsuario") );
String resposta = "";
try {
CityController cc = new CityController( idUsuario );
IStaticElementList lista = cc.getCitiesInBBOX( bleft, bbottom, bright, btop );
resposta = lista.asJson();
} catch ( Exception e ) {
e.printStackTrace();
}
try {
HttpServletResponse response = (HttpServletResponse)ActionContext.getContext().get(StrutsStatics.HTTP_RESPONSE);
response.setCharacterEncoding("UTF-8");
response.getWriter().write(resposta);
} catch (IOException ex) {
ex.printStackTrace();
}
return "ok";
}
}
Hybernate to database access. Don't forget to keep the domains. See Domain Driven Design. Mail me if in doubt (see my profile).
You could use the Google Fusion tables version (see related blog post) of the Natural Earth world boundaries dataset with the Google Maps API, as in these answers:
Best Answer
Very simple answer is: Somekind way to read GPS data. Convert it to Point(' longitude lattitude) format, tool to send it to server side and store it in PostGIS ( you need to add from user, now() to it. Do PostGIS search for mentioned Point 'SELECT users, st_distance(the_geom, point) from somwtable where ST_distance(the_geom, point) < "some sane value". Return users, distance rows to back android and display them ).
So all you need is PostGIS database.