This app's function/purpose is to use Google Maps API to get geographic data and render locations on maps with editable pins (much like... many apps these days- it is kind of becoming an expectation for any application/service involving a location street address).
In this way you can record or plan the state(s) of an event or location at some particular street address. Or just have a geographic representation of some important locations that you can then print and have a custom map for.
This is a proof-of-concept app illustrating what you can do with a little JavaScript, a web app and the Google Maps API
The code below takes locations records (containing the lat/long of the geographic coordinate) from a database and then initializes the Google Map with some options (I omitted many for brevity). The main interesting thing the code does below, is when it renders the pins (addMarker() function) it adds an event listener to delegate the task of popping up an ASP.NET Core-bound edit modal when a user clicks the pin.
On the Add and Update side as far as mapping Lat/Long from Street, City, State- that is all handled by the incredibly useful GoogleLocationService provided as a Nuget package for .NET Core apps.
Other than that it is just standard JavaScript- Google Maps API does virtually all of the geocoding and map visualization heavy lifting.
The crux of the utilization of the API code (callback and map rendering) is this:
<script>
function initMap() {
var map = new google.maps.Map(
document.getElementById('map'),
{
center: new google.maps.LatLng(@Model.CenterLat, @Model.CenterLong),
zoom: 8
}
);
var pins = @Html.Raw(Json.Serialize(@Model.Locations));
for (var i = 0; i < pins.length; i++) {
var myLatLng = {
lat: pins[i].lat,
lng: pins[i].long
};
addMarker(myLatLng, map, pins[i]);
}
}
function addMarkerAsync(location, map) {
new google.maps.Marker({
position: location,
title: 'Home Center',
});
marker.setMap(map);
}
function addMarker(location, map, pin) {
var marker = new google.maps.Marker({
position: location,
title: '...something dyanmic...',
});
var infowindow = new google.maps.InfoWindow({
content: ''
});
function AsyncDisplayString() {
$.ajax({
type: 'GET',
url: '/Home/GetLocationModalInfo',
dataType: "HTML",
contentType: 'application/json',
traditional: true,
data: pin,
success: function (result) {
debugger;
infowindow.setContent('<div style="background-color:#000000;">' + result + '</div>');
infowindow.open(map, marker);
},
error: function (arg) {
alert('Error');
}
});
}
google.maps.event.addListener(marker, 'click', function () {
AsyncDisplayString(map, marker)
});
marker.setMap(map);
}
</script>
And then this Controller Action that uses GoogleLocationService to get coordinates by address:
[HttpPost]
public IActionResult AddLocation(LocationModel location)
{
string address = location.StreetAddress1.Replace(" ", "+") + "," + location.City.Replace(" ", "+") + "," + location.State.Replace(" ", "+");
MapPoint coords = _locationService.GetLatLongFromAddress(address);
location.Lat = (decimal)coords.Latitude;
location.Long = (decimal)coords.Longitude;
using (var db = new SqlConnection(_configuration.GetConnectionString("DefaultConnection")))
{
db.Open();
string sql = @"INSERT INTO [Locations].[dbo].[Locations] ([Name], [Contact], [Email], [Website], [Phone], [StreetAddress1], [StreetAddress2], [City]"
+ ",[State], [Zip], [LocationContact], [PrimaryContact], [Notes], [Type], [Lat], [Long], [Petitions], [Flyers], [Posters], [LastPickUpDateTime], [LastOutOfStockDateTime], LastDropoffDateTime"
+ ",[AllTimeOutofStock],[Unsupportive],[VolunteerInterest])"
+ " VALUES ('" + location.Name + "','" + location.Contact + "','" + location.Email + "','" + location.Website + "','" + location.Phone + "','" + location.StreetAddress1 + "','" + location.StreetAddress1 + "','" + location.City + "'"
+ ",'" + location.State + "','" + location.Zip + "', -1, -1,'" + location.Notes + "', 1, " + location.Lat + "," + location.Long + "," + location.Petitions + "," + location.Flyers + "," + location.Posters + ",'" + location.LastPickUpDateTime + "','" + location.LastOutOfStockDateTime + "','" + location.LastDropoffDateTime + "', 0, 0, 1) " + ";";
db.Execute(sql);
}
var model = GetDefaultMapView();
model.KeyString = _configuration["MapsAPIKey"].ToString();
return View("Map", model);
}
This is a proof-of-concept app illustrating what you can do with a little JavaScript, a web app and the Google Maps API
As you can see the Google Maps API provides a lot of opportunity for your application- don't underestimate the power of location-based data. With the tools at our disposal today the functionality of applications is being limited less by available algorithms/frameworks/tools- but rather, our imagination.
