I have the following shapefile of a 10x10 degree latitude/longitude grid that I created in QGIS. I can read it into R using the rgdal package.
Grid<-readOGR(".","GridShapeFile")
It has the following attributes and structure.
summary(Grid)
Object of class SpatialPolygonsDataFrame
Coordinates:
min max
x -180 190
y -100 90
Is projected: FALSE
proj4string :
[+proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0]
Data attributes:
ID XMIN XMAX YMIN YMAX
Min. : 0.0 Min. :-180 Min. :-170 Min. :-100 Min. :-90
1st Qu.:175.5 1st Qu.: -90 1st Qu.: -80 1st Qu.: -60 1st Qu.:-50
Median :351.0 Median : 0 Median : 10 Median : -10 Median : 0
Mean :351.0 Mean : 0 Mean : 10 Mean : -10 Mean : 0
3rd Qu.:526.5 3rd Qu.: 90 3rd Qu.: 100 3rd Qu.: 40 3rd Qu.: 50
Max. :702.0 Max. : 180 Max. : 190 Max. : 80 Max. : 90
# An example row of the data
Grid[50,]
class : SpatialPolygonsDataFrame
features : 1
extent : -60, -50, 70, 80 (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84+towgs84=0,0,0
variables : 5
names : ID, XMIN, XMAX, YMIN, YMAX
min values : 49, -60, -50, 70, 80
max values : 49, -60, -50, 70, 80
I would like to learn how to create this same grid/shapefile entirely within R, rather than in QGIS, as well as grids of other sizes (1x1,5x5,etc.). The ultimate goal is to use over() in the sp package to overlay this grid onto another file of polygons and count the number of grids intersected by each polygon. I already know how to do this next step (I think), I just want to know how to generate the grid layer in R.