Polygon borders for 389 hexagonal grid cells covering Oregon, USA,
in polygon format.
data (oregon.grid)A data frame with 3112 rows and 2 columns (the components
"x" and "y").
The polygon format used for these grid cell boundaries is a slight
variation from the standard R/S format. Each cell polygon is
described by seven coordinate pairs, the last repeating the first.
Prior to the first coordinate pair of each cell is a row containing
NA in the "y" column and, in the "x" column, an
identifier for the cell. The identifiers are the same as the
row names in oregon.bird.dist and
oregon.env.vars. See map.groups for
how the linkage is made in mapping.
These grid cells are extracted from a larger set covering the conterminous United States and adjacent parts of Canada and Mexico, as described in White et al. (1992). Only cells with at least 50 percent of their area contained within the state of Oregon are included.
The map projection for the coordinates, as well as the point
coordinates in oregon.env.vars, is the Lambert
Conformal Conic with standard parallels at 33 and 45
degrees North latitude, with the longitude of the central
meridian at 120 degrees, 30 minutes West longitude,
and with the projection origin latitude at 41 degrees,
45 minutes North latitude.
White, D., Kimerling, A.J., Overton, W.S. (1992) Cartographic and geometric components of a global sampling design for environmental monitoring, Cartography and Geographic Information Systems, 19(1), 5-22.