GPS Exchange Format library/CLI in OCaml
anil.recoil.org
1(** Example using GPX with real Eio effects-based API
2
3 This demonstrates the real Eio-based API with structured concurrency
4 and proper resource management.
5**)
6
7open Gpx_eio
8
9let main env =
10 try
11 let fs = Eio.Stdenv.fs env in
12
13 (* Create some GPS coordinates *)
14 let lat1 = Gpx.latitude 37.7749 |> Result.get_ok in
15 let lon1 = Gpx.longitude (-122.4194) |> Result.get_ok in
16 let lat2 = Gpx.latitude 37.7849 |> Result.get_ok in
17 let lon2 = Gpx.longitude (-122.4094) |> Result.get_ok in
18
19 (* Create waypoints *)
20 let waypoint1 = make_waypoint ~fs ~lat:(Gpx.latitude_to_float lat1) ~lon:(Gpx.longitude_to_float lon1) ~name:"San Francisco" () in
21 let waypoint2 = make_waypoint ~fs ~lat:(Gpx.latitude_to_float lat2) ~lon:(Gpx.longitude_to_float lon2) ~name:"Near SF" () in
22
23 (* Create a simple track from coordinates *)
24 let track = make_track_from_coords ~fs ~name:"SF Walk" [
25 (37.7749, -122.4194);
26 (37.7759, -122.4184);
27 (37.7769, -122.4174);
28 (37.7779, -122.4164);
29 ] in
30
31 (* Create a route *)
32 let route = make_route_from_coords ~fs ~name:"SF Route" [
33 (37.7749, -122.4194);
34 (37.7849, -122.4094);
35 ] in
36
37 (* Create GPX document with all elements *)
38 let gpx = Gpx.make_gpx ~creator:"eio-example" in
39 let gpx = { gpx with
40 waypoints = [waypoint1; waypoint2];
41 tracks = [track];
42 routes = [route];
43 } in
44
45 Printf.printf "Created GPX document with:\\n";
46 print_stats gpx;
47 Printf.printf "\\n";
48
49 (* Write to file with validation *)
50 write_validated ~fs "example_output.gpx" gpx;
51 Printf.printf "Wrote GPX to example_output.gpx\\n";
52
53 (* Read it back and verify *)
54 let gpx2 = read_validated ~fs "example_output.gpx" in
55 Printf.printf "Read back GPX document with %d waypoints, %d tracks, %d routes\\n"
56 (List.length gpx2.waypoints) (List.length gpx2.tracks) (List.length gpx2.routes);
57
58 (* Extract coordinates from track *)
59 match gpx2.tracks with
60 | track :: _ ->
61 let coords = track_coords track in
62 Printf.printf "Track coordinates: %d points\\n" (List.length coords);
63 List.iteri (fun i (lat, lon) ->
64 Printf.printf " Point %d: %.4f, %.4f\\n" i lat lon
65 ) coords
66 | [] -> Printf.printf "No tracks found\\n";
67
68 Printf.printf "\\nEio example completed successfully!\\n"
69
70 with
71 | Gpx.Gpx_error err ->
72 let error_msg = match err with
73 | Gpx.Invalid_xml s -> "Invalid XML: " ^ s
74 | Gpx.Invalid_coordinate s -> "Invalid coordinate: " ^ s
75 | Gpx.Missing_required_attribute (elem, attr) ->
76 Printf.sprintf "Missing required attribute '%s' in element '%s'" attr elem
77 | Gpx.Missing_required_element s -> "Missing required element: " ^ s
78 | Gpx.Validation_error s -> "Validation error: " ^ s
79 | Gpx.Xml_error s -> "XML error: " ^ s
80 | Gpx.IO_error s -> "I/O error: " ^ s
81 in
82 Printf.eprintf "GPX Error: %s\\n" error_msg;
83 exit 1
84 | exn ->
85 Printf.eprintf "Unexpected error: %s\\n" (Printexc.to_string exn);
86 exit 1
87
88let () = Eio_main.run main