diff --git a/MapControl/Shared/PolarStereographicProjection.cs b/MapControl/Shared/PolarStereographicProjection.cs
index 0f461601..8fc545cd 100644
--- a/MapControl/Shared/PolarStereographicProjection.cs
+++ b/MapControl/Shared/PolarStereographicProjection.cs
@@ -15,14 +15,6 @@ namespace MapControl
     /// </summary>
     public class PolarStereographicProjection : MapProjection
     {
-        public PolarStereographicProjection(bool north)
-        {
-            LatitudeOfOrigin = north ? 90d : -90d;
-            ScaleFactor = 0.994;
-            FalseEasting = 2e6;
-            FalseNorthing = 2e6;
-        }
-
         public override double GridConvergence(double latitude, double longitude)
         {
             return Math.Sign(LatitudeOfOrigin) * (longitude - CentralMeridian);
@@ -99,9 +91,13 @@ namespace MapControl
         {
         }
 
-        public Wgs84UpsNorthProjection(string crsId) : base(true)
+        public Wgs84UpsNorthProjection(string crsId)
         {
             CrsId = crsId;
+            ScaleFactor = 0.994;
+            LatitudeOfOrigin = 90d;
+            FalseEasting = 2e6;
+            FalseNorthing = 2e6;
         }
     }
 
@@ -117,9 +113,13 @@ namespace MapControl
         {
         }
 
-        public Wgs84UpsSouthProjection(string crsId) : base(false)
+        public Wgs84UpsSouthProjection(string crsId)
         {
             CrsId = crsId;
+            ScaleFactor = 0.994;
+            LatitudeOfOrigin = -90d;
+            FalseEasting = 2e6;
+            FalseNorthing = 2e6;
         }
     }
 }
diff --git a/MapControl/Shared/TransverseMercatorProjection.cs b/MapControl/Shared/TransverseMercatorProjection.cs
index c1db6dad..dcfc24d1 100644
--- a/MapControl/Shared/TransverseMercatorProjection.cs
+++ b/MapControl/Shared/TransverseMercatorProjection.cs
@@ -29,17 +29,10 @@ namespace MapControl
         private readonly double d3; // δ3
         private readonly double A;
 
-        public TransverseMercatorProjection(
-            double equatorialRadius, double flattening,
-            double scaleFactor, double centralMeridian,
-            double falseEasting, double falseNorthing = 0d)
+        protected TransverseMercatorProjection(double equatorialRadius, double flattening)
         {
             EquatorialRadius = equatorialRadius;
             Flattening = flattening;
-            ScaleFactor = scaleFactor;
-            CentralMeridian = centralMeridian;
-            FalseEasting = falseEasting;
-            FalseNorthing = falseNorthing;
 
             n = flattening / (2d - flattening);
             m = 2d * Math.Sqrt(n) / (1d + n);
@@ -58,12 +51,14 @@ namespace MapControl
             A = equatorialRadius / (1d + n) * (1d + n2 / 4d + n2 * n2 / 64d);
         }
 
-        public TransverseMercatorProjection(
-            double equatorialRadius, double flattening,
-            double scaleFactor, int utmZone, bool north = true)
-            : this(equatorialRadius, flattening,
-                  scaleFactor, utmZone * 6d - 183d, 5e5, north ? 0d : 1e7)
+        public TransverseMercatorProjection(string crsId, double equatorialRadius, double flattening, int utmZone, bool north = true)
+            : this(equatorialRadius, flattening)
         {
+            CrsId = crsId;
+            ScaleFactor = 0.9996;
+            CentralMeridian = utmZone * 6d - 183d;
+            FalseEasting = 5e5;
+            FalseNorthing = north ? 0d : 1e7;
         }
 
         public override double GridConvergence(double latitude, double longitude)
diff --git a/MapControl/Shared/TransverseMercatorProjectionSnyder.cs b/MapControl/Shared/TransverseMercatorProjectionSnyder.cs
index f08b0505..5f4c46e1 100644
--- a/MapControl/Shared/TransverseMercatorProjectionSnyder.cs
+++ b/MapControl/Shared/TransverseMercatorProjectionSnyder.cs
@@ -15,26 +15,6 @@ namespace MapControl
     /// </summary>
     public class TransverseMercatorProjectionSnyder : MapProjection
     {
-        public TransverseMercatorProjectionSnyder(
-            double equatorialRadius, double flattening, double scaleFactor,
-            double centralMeridian, double latitudeOfOrigin,
-            double falseEasting, double falseNorthing = 0d)
-        {
-            EquatorialRadius = equatorialRadius;
-            Flattening = flattening;
-            ScaleFactor = scaleFactor;
-            CentralMeridian = centralMeridian;
-            LatitudeOfOrigin = latitudeOfOrigin;
-            FalseEasting = falseEasting;
-            FalseNorthing = falseNorthing;
-        }
-
-        public TransverseMercatorProjectionSnyder(int utmZone, bool north = true)
-            : this(Wgs84EquatorialRadius, Wgs84Flattening,
-                  0.9996, utmZone * 6d - 183d, 0d, 5e5, north ? 0d : 1e7)
-        {
-        }
-
         public override double GridConvergence(double latitude, double longitude)
         {
             // φ
diff --git a/MapControl/Shared/UtmProjections.cs b/MapControl/Shared/UtmProjections.cs
index 1496b880..a99427f5 100644
--- a/MapControl/Shared/UtmProjections.cs
+++ b/MapControl/Shared/UtmProjections.cs
@@ -18,7 +18,7 @@ namespace MapControl
         public int Zone { get; }
 
         public Wgs84UtmProjection(int zone, bool north)
-            : base(Wgs84EquatorialRadius, Wgs84Flattening, 0.9996, zone, north)
+            : base($"EPSG:{(north ? 32600 : 32700) + zone}", Wgs84EquatorialRadius, Wgs84Flattening, zone, north)
         {
             if (zone < FirstZone || zone > LastZone)
             {
@@ -26,7 +26,6 @@ namespace MapControl
             }
 
             Zone = zone;
-            CrsId = $"EPSG:{(north ? 32600 : 32700) + zone}";
         }
     }
 
@@ -43,7 +42,7 @@ namespace MapControl
         public int Zone { get; }
 
         public Etrs89UtmProjection(int zone)
-            : base(6378137d, 1d / 298.257222101, 0.9996, zone) // GRS 1980
+            : base($"EPSG:{25800 + zone}", 6378137d, 1d / 298.257222101, zone) // GRS 1980
         {
             if (zone < FirstZone || zone > LastZone)
             {
@@ -51,7 +50,6 @@ namespace MapControl
             }
 
             Zone = zone;
-            CrsId = $"EPSG:{25800 + zone}";
         }
     }
 
@@ -68,7 +66,7 @@ namespace MapControl
         public int Zone { get; }
 
         public Nad83UtmProjection(int zone)
-            : base(6378137d, 1d / 298.257222101, 0.9996, zone) // GRS 1980
+            : base($"EPSG:{26900 + zone}", 6378137d, 1d / 298.257222101, zone) // GRS 1980
         {
             if (zone < FirstZone || zone > LastZone)
             {
@@ -76,7 +74,6 @@ namespace MapControl
             }
 
             Zone = zone;
-            CrsId = $"EPSG:{26900 + zone}";
         }
     }
 
@@ -93,7 +90,7 @@ namespace MapControl
         public int Zone { get; }
 
         public Nad27UtmProjection(int zone)
-            : base(6378206.4, 1d / 294.978698213898, 0.9996, zone) // Clarke 1866
+            : base($"EPSG:{26700 + zone}", 6378206.4, 1d / 294.978698213898, zone) // Clarke 1866
         {
             if (zone < FirstZone || zone > LastZone)
             {
@@ -101,7 +98,6 @@ namespace MapControl
             }
 
             Zone = zone;
-            CrsId = $"EPSG:{26700 + zone}";
         }
     }
 }