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Updated GeoApiProjectionFactory

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Clemens 2022-01-22 20:32:17 +01:00
parent e6b25c2f8d
commit 45b5d037bb
3 changed files with 11 additions and 38 deletions
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40
MapProjections/Shared/GeoApiProjectionFactory.cs
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@ -2,11 +2,6 @@
// © 2022 Clemens Fischer
// Licensed under the Microsoft Public License (Ms-PL)
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Net.Http;
namespace MapControl.Projections
{
public class GeoApiProjectionFactory : MapProjectionFactory
@ -22,10 +17,7 @@ namespace MapControl.Projections
public const int Wgs84UtmSouthLast = 32760;
public const int Wgs84UpsSouth = 32761;
private readonly Dictionary<int, string> wkts = new Dictionary<int, string>();
private readonly HttpClient httpClient = new HttpClient();
public override MapProjection CreateProjection(string crsId)
public override MapProjection GetProjection(string crsId)
{
MapProjection projection = null;
@ -62,17 +54,16 @@ namespace MapControl.Projections
break;
default:
projection = new GeoApiProjection(GetWkt(epsgCode));
break;
}
}
return projection ?? base.CreateProjection(crsId);
return projection ?? base.GetProjection(crsId);
}
private static string GetEtrs89UtmWkt(int epsgCode)
{
const string etrs89UtmWktFormat
const string wktFormat
= "PROJCS[\"ETRS89 / UTM zone {1}N\","
+ "GEOGCS[\"ETRS89\","
+ "DATUM[\"European_Terrestrial_Reference_System_1989\","
@ -97,29 +88,10 @@ namespace MapControl.Projections
+ "AXIS[\"Northing\",NORTH],"
+ "AUTHORITY[\"EPSG\",\"{0}\"]]";
int centralMeridian = 6 * (epsgCode - Etrs89UtmNorthFirst) - 15;
var zone = epsgCode % 100;
var centralMeridian = 6 * (epsgCode - Etrs89UtmNorthFirst) - 15;
return string.Format(etrs89UtmWktFormat, epsgCode, epsgCode - 25800, centralMeridian);
}
private string GetWkt(int epsgCode)
{
if (!wkts.TryGetValue(epsgCode, out string wkt))
{
var url = string.Format("https://epsg.io/{0}.wkt", epsgCode);
try
{
wkt = httpClient.GetStringAsync(url).Result; // potential deadlock?
wkts[epsgCode] = wkt;
}
catch (Exception ex)
{
Debug.WriteLine($"GeoApiProjectionFactory.GetWkt({epsgCode}): {url}: {ex.Message}");
}
}
return wkt;
return string.Format(wktFormat, epsgCode, zone, centralMeridian);
}
}
}