MGRS Polar region grid/graticule lines incorrect

[NormOlsen]

The MGRS graticule and the 100Km grid in the polar regions are incorrect. There are line extending past where they should, missing lines, and the polar region is often omitted altogether depending upon the frame boundary provided.

[NormOlsen]

Corrected by a submission which produced revision 4351. The submission was substantial, and included two new code modules:

CoordsysMgrsMajorRegion.h. CoordSysMgrsMajorRegion.cpp

1> The generation of MGRS regions was originally accomplished by the 6x8 graticule generator. This was replaced by the two new objects referenced above. Thus, MGRS major region generation now accounts for the difference of Band X from other bands and also the rather strange stuff that goes on in the vicinity of Norway.

2> Logic was added to the MGRS Zone object generator so that the provided frame boundary is tested to see if it includes either pole. If so, the MGRS Zone object generator generates zones for the respective polar regions regardless of the latitudes of the bounding box.

3> The boundary of the the polar regions as sent off to the MGRS Zone object was changed from rectangular to a representation of a complete parallel of latitude in the frame coordinate system (usually a circle).

4> 100Km block designation code was added so that the 100Km grid in the polar regions is properly labeled.

5> Problems in the clipper where the line being clipped passed exactly through a vertex in the clipping boundary were corrected.