feat: finding nearby points of interest (POIs) for location-based ser…

example/main.ml

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+open Rtree
+open Printf
+(* Sample Point of Interest data structure *)
+type poi = {
+  name : string;
+  latitude : float;
+  longitude : float;
+}
+
+
+module Rtree =  struct
+
+(* Function to insert POIs into the R-tree *)
+let insert_pois rtree pois =
+  List.iter (fun poi -> Rtree.insert rtree (poi.latitude, poi.longitude, poi)) pois
+
+(* Function to load geospatial data from a CSV file *)
+let load_geospatial_data_from_csv filename =
+  let ic = open_in filename in
+  let csv = Csv.of_channel ~has_header:true ic in
+  let pois = ref [] in
+  Csv.iter
+    (fun row ->
+      let name = row.(0) in
+      let latitude = float_of_string row.(1) in
+      let longitude = float_of_string row.(2) in
+      pois := { name; latitude; longitude } :: !pois
+    )
+    csv;
+  close_in ic;
+  List.rev !pois
+
+(* Example usage with geospatial data from a CSV file *)
+let () =
+  let rtree = Rtree.create () in
+
+  (* Load geospatial data from external csv file *)
+  let csv =
+    List.map (fun name -> name, Csv.load name)
+             [ "example/pois.csv"]
+
+
+  (* Perform real-world spatial queries *)
+  let nearby_pois = find_nearby_pois rtree 42.3601 (-71.0589) 1.0 in
+  List.iter (fun poi -> Printf.printf("Nearby: %s\n" poi.name)) nearby_pois

example/pois.csv

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+name,latitude,longitude
+Restaurant A,42.3601,-71.0589
+Cafe B,42.3605,-71.0587
+Park C,42.3609,-71.0585