R/create_grid_s3m.R
create_s3m_grid.RdCreate the rectangular S3M grid given a value of d of the farthest distance of a village from a sampling point.
create_s3m_grid(input, d, buffer, country, output = "points")
| input | A class SpatialPolygons or SpatialPolygonsDataFrame object of the area to be gridded. |
|---|---|
| d | A numeric value for length (in kilometres) of the maximum distance
of a village/community from a sampling point. This can be the output of
the function |
| buffer | A numeric value for distance (in kilometres) to expand the
borders of the given spatial object |
| country | Name of country where sampling area is located. This is used
to determine the appropriate UTM projection to transform |
| output | A character value specifying type of output required. Can be either of two options: "points" for a class SpatialPoints output of the sampling point locations based on the S3M grid or "lines" for a class SpatialLines output of the rectangular S3M grid. Default is "points". |
based on S3M sampling approach designed by Mark Myatt and Ernest Guevarra
Either a class SpatialLines object if output is "lines" or
a class SpatialPoints object if output is "points"
# S3M grid of Sennar state, Sudan based on a d of 12 kms create_s3m_grid(input = sudan01[sudan01$STATE == "Sennar", ], d = 12, buffer = 6, country = "Sudan", output = "lines")#> Warning: Discarded datum WGS_1984 in CRS definition, #> but +towgs84= values preserved#> Warning: Discarded datum Unknown based on WGS84 ellipsoid in CRS definition#> Warning: CRS object has comment, which is lost in output#> Warning: Discarded datum Unknown based on WGS84 ellipsoid in CRS definition, #> but +towgs84= values preserved#> Warning: Discarded datum Unknown based on Clarke 1880 mod. ellipsoid in CRS definition, #> but +towgs84= values preserved#> Warning: CRS object has comment, which is lost in output#> Warning: Discarded datum Unknown based on Clarke 1880 mod. ellipsoid in CRS definition, #> but +towgs84= values preserved#> Warning: Discarded datum WGS_1984 in CRS definition, #> but +towgs84= values preserved#> Warning: CRS object has comment, which is lost in output#> Warning: Discarded datum Unknown based on Clarke 1880 mod. ellipsoid in CRS definition, #> but +towgs84= values preserved#> Warning: Discarded datum WGS_1984 in CRS definition, #> but +towgs84= values preserved#> class : SpatialLines #> features : 47 #> extent : 32.80014, 35.83637, 11.61406, 14.21312 (xmin, xmax, ymin, ymax) #> crs : +proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs