XAML-Map-Control/MapProjections/Shared/GeoApiProjectionFactory.cs

// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
// © 2022 Clemens Fischer
// Licensed under the Microsoft Public License (Ms-PL)

using System.Collections.Generic;

namespace MapControl.Projections
{
    public class GeoApiProjectionFactory : MapProjectionFactory
    {
        public const int WorldMercator = 3395;
        public const int WebMercator = 3857;
        public const int Ed50UtmFirst = 23028;
        public const int Ed50UtmLast = 23038;
        public const int Etrs89UtmFirst = 25828;
        public const int Etrs89UtmLast = 25838;
        public const int Wgs84UtmNorthFirst = 32601;
        public const int Wgs84UtmNorthLast = 32660;
        public const int Wgs84UpsNorth = 32661;
        public const int Wgs84UtmSouthFirst = 32701;
        public const int Wgs84UtmSouthLast = 32760;
        public const int Wgs84UpsSouth = 32761;

        public Dictionary<string, string> CoordinateSystemWkts { get; } = new Dictionary<string, string>();

        public override MapProjection GetProjection(string crsId)
        {
            MapProjection projection = null;

            if (CoordinateSystemWkts.TryGetValue(crsId, out string wkt))
            {
                projection = new GeoApiProjection(wkt);
            }
            else if (crsId.StartsWith("EPSG:") && int.TryParse(crsId.Substring(5), out int epsgCode))
            {
                switch (epsgCode)
                {
                    case WorldMercator:
                        projection = new WorldMercatorProjection();
                        break;

                    case WebMercator:
                        projection = new WebMercatorProjection();
                        break;

                    case int c when c >= Ed50UtmFirst && c <= Ed50UtmLast:
                        projection = new Ed50UtmProjection(epsgCode % 100);
                        break;

                    case int c when c >= Etrs89UtmFirst && c <= Etrs89UtmLast:
                        projection = new Etrs89UtmProjection(epsgCode % 100);
                        break;

                    case int c when c >= Wgs84UtmNorthFirst && c <= Wgs84UtmNorthLast:
                        projection = new Wgs84UtmProjection(epsgCode % 100, true);
                        break;

                    case int c when c >= Wgs84UtmSouthFirst && c <= Wgs84UtmSouthLast:
                        projection = new Wgs84UtmProjection(epsgCode % 100, false);
                        break;

                    case Wgs84UpsNorth:
                        projection = new UpsNorthProjection();
                        break;

                    case Wgs84UpsSouth:
                        projection = new UpsSouthProjection();
                        break;

                    default:
                        break;
                }
            }

            return projection ?? base.GetProjection(crsId);
        }
    }
}