windfarmGA (version 2.2.3)

grid_area: Make a grid from a Polygon

Description

Create a grid from a given polygon and with a certain resolution and proportionality. The center points of each grid cell represent possible locations for wind turbines.

Usage

grid_area(shape, resol = 500, prop = 1, plotGrid = FALSE)

Arguments

shape

Shape file of the considered area

resol

The resolution of the grid in meters. Default is 500

prop

A factor used for grid calculation. Determines the percentage a grid has to overlay the considered area to be represented as grid cell. Default is 1.

plotGrid

Logical value indicating whether resulting grid should be plotted or not. Default is FALSE.

Value

Returns a list with 2 elements. List element 1 will have the grid cell IDS, and the X and Y coordinates of the centers of each grid cell. List element 2 is the grid as SpatialPolygons, which is used for plotting purposes.

References

http://rfunctions.blogspot.co.at/2014/12/gridfilter-intersect-grid-with-shape.html

See Also

Other Helper Functions: dup_coords, getDEM, getISO3, get_grids, hexa_area, isSpatial, permutations, readintegerSel, readinteger, splitAt, tess2SPdf, windata_format

Examples

# NOT RUN {
library(sp)
library(raster)
library(rgeos)

## Exemplary input Polygon with 2km x 2km:
Polygon1 <- Polygon(rbind(c(0, 0), c(0, 2000),
c(2000, 2000), c(2000, 0)))
Polygon1 <- Polygons(list(Polygon1),1);
Polygon1 <- SpatialPolygons(list(Polygon1))
Projection <- "+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000
+ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs"
proj4string(Polygon1) <- CRS(Projection)

## Create a Grid
grid_area(Polygon1,200,1,TRUE)
grid_area(Polygon1,400,1,TRUE)


## Examplary irregular input Polygon
Polygon1 <- Polygon(rbind(c(0, 20), c(0, 200),
                          c(2000, 2000), c(3000, 0)))
Polygon1 <- Polygons(list(Polygon1),1);
Polygon1 <- SpatialPolygons(list(Polygon1))
Projection <- "+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000
+ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs"
proj4string(Polygon1) <- CRS(Projection)

## Create a Grid
grid_area(Polygon1,200,1,TRUE)
grid_area(Polygon1,200,0.5,TRUE)
grid_area(Polygon1,200,0.1,TRUE)
grid_area(Polygon1,400,1,TRUE)
grid_area(Polygon1,400,0.5,TRUE)
grid_area(Polygon1,400,0.1,TRUE)

# }