Polygons identifying map sections (collections of 16 sheets) for Index Map. Each section is further divided into 4 quadrants, NW, NE, SW and SE. Sections are again broken into
16 map sheets, each being 1500 feet by 1000 feet in size, and numbered 1
through 16, numbered across 4 rows within each section. These sheets are
generally identified by a combination of section number and sheet number,
such as 44-11.