Correct for distortion of globe.

In the timezone widget, locations in the far north -- Inuvik,
Thule, Longyearbyen -- were displayed too far south, because the
map location calculation assumes a linear gradient, which places
90 degrees north at about 70 degrees. Change calculation to
pretend the world is flat south of 62 degrees north, and then
'bend' the remaining 28 degrees of latitude to the top of the
image. This puts most places in the right spot, although Yellowknife
is now on the south shore of Great Slave.

Fort Nelson should be north of Dawson Creek, too -- the math still
needs a little work.

While here, put Antarctica in the south, otherwise Rothera keeps
showing up in Greenland.

src/modules/locale/timezonewidget/timezonewidget.cpp

@@ -20,8 +20,12 @@
  *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <cmath>
+
 #include "timezonewidget.h"
 
+constexpr double MATH_PI = 3.14159265;
+
 TimeZoneWidget::TimeZoneWidget(QWidget* parent) :
     QWidget(parent)
 {
@@ -98,6 +102,17 @@ QPoint TimeZoneWidget::getLocationPosition(double longitude, double latitude) {
     double x = (width / 2.0 + (width / 2.0) * longitude / 180.0) + MAP_X_OFFSET * width;
     double y = (height / 2.0 - (height / 2.0) * latitude / 90.0) + MAP_Y_OFFSET * height;
 
+    //Far north, the MAP_Y_OFFSET no longer holds, cancel the Y offset; it's noticeable
+    // from 62 degrees north, so scale those 28 degrees as if the world is flat south
+    // of there, and we have a funny "rounded" top of the world. In practice the locations
+    // of the different cities / regions looks ok -- at least Thule ends up in the right
+    // country, and Inuvik isn't in the ocean.
+    if (latitude > 62.0)
+        y -= sin(MATH_PI * (latitude - 62.0) / 56.0) * MAP_Y_OFFSET * height;
+    // Antarctica isn't shown on the map, but you could try clicking there
+    if (latitude < -60)
+        y = height - 1;
+
     if (x < 0)
         x = width+x;
     if (x >= width)