The goal of localgrid is to make it easy to define coordinate
reference systems in the Oblique Mercator projection for new or existing
arbitrary floating grids.
You can install localgrid from Github with:
# install.packages("remotes")
remotes::install_github("crowcanyon/localgrid")library(localgrid)
#> Loading required package: magrittr
# Define a floating CRS for a new grid
define_new_grid(
pt_0_geo = c(-108.51, 37.385),
pt_0_grid = c(500, 500),
name = "Great New Grid"
)
#> Coordinate Reference System:
#> User input: +proj=omerc +lat_0=37.385 +lonc=-108.51 +alpha=0 +gamma=0 +k_0=1 +x_0=500 +y_0=500
#> wkt:
#> PROJCRS["Great New Grid",
#> BASEGEOGCRS["Great New Grid",
#> DATUM["World Geodetic System 1984",
#> ELLIPSOID["WGS 84",6378137,298.257223563,
#> LENGTHUNIT["metre",1]],
#> ID["EPSG",6326]],
#> PRIMEM["Greenwich",0,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8901]]],
#> CONVERSION["Great New Grid",
#> METHOD["Hotine Oblique Mercator (variant B)",
#> ID["EPSG",9815]],
#> PARAMETER["Latitude of projection centre",37.385,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8811]],
#> PARAMETER["Longitude of projection centre",-108.51,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8812]],
#> PARAMETER["Azimuth of initial line",0,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8813]],
#> PARAMETER["Angle from Rectified to Skew Grid",0,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8814]],
#> PARAMETER["Scale factor on initial line",1,
#> SCALEUNIT["unity",1],
#> ID["EPSG",8815]],
#> PARAMETER["Easting at projection centre",500,
#> LENGTHUNIT["metre",1],
#> ID["EPSG",8816]],
#> PARAMETER["Northing at projection centre",500,
#> LENGTHUNIT["metre",1],
#> ID["EPSG",8817]]],
#> CS[Cartesian,2],
#> AXIS["(E)",east,
#> ORDER[1],
#> LENGTHUNIT["metre",1,
#> ID["EPSG",9001]]],
#> AXIS["(N)",north,
#> ORDER[2],
#> LENGTHUNIT["metre",1,
#> ID["EPSG",9001]]]]
# Or, define a floating CRS for a legacy grid
define_legacy_grid(
pt_0_geo = c(-108.51, 37.385),
pt_0_grid = c(500, 500),
pt_1_geo = c(-108.511, 37.384),
pt_1_grid = c(360, 380),
name = "Screwy Legacy Grid"
)
#> Coordinate Reference System:
#> User input: +proj=omerc +lat_0=37.385 +lonc=-108.51 +alpha=-10.8099400559583 +gamma=0 +k_0=1.29863131831123 +x_0=500 +y_0=500
#> wkt:
#> PROJCRS["Screwy Legacy Grid",
#> BASEGEOGCRS["Screwy Legacy Grid",
#> DATUM["World Geodetic System 1984",
#> ELLIPSOID["WGS 84",6378137,298.257223563,
#> LENGTHUNIT["metre",1]],
#> ID["EPSG",6326]],
#> PRIMEM["Greenwich",0,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8901]]],
#> CONVERSION["Screwy Legacy Grid",
#> METHOD["Hotine Oblique Mercator (variant B)",
#> ID["EPSG",9815]],
#> PARAMETER["Latitude of projection centre",37.385,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8811]],
#> PARAMETER["Longitude of projection centre",-108.51,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8812]],
#> PARAMETER["Azimuth of initial line",-10.8099400559583,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8813]],
#> PARAMETER["Angle from Rectified to Skew Grid",0,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8814]],
#> PARAMETER["Scale factor on initial line",1.29863131831123,
#> SCALEUNIT["unity",1],
#> ID["EPSG",8815]],
#> PARAMETER["Easting at projection centre",500,
#> LENGTHUNIT["metre",1],
#> ID["EPSG",8816]],
#> PARAMETER["Northing at projection centre",500,
#> LENGTHUNIT["metre",1],
#> ID["EPSG",8817]]],
#> CS[Cartesian,2],
#> AXIS["(E)",east,
#> ORDER[1],
#> LENGTHUNIT["metre",1,
#> ID["EPSG",9001]]],
#> AXIS["(N)",north,
#> ORDER[2],
#> LENGTHUNIT["metre",1,
#> ID["EPSG",9001]]]]
# You can also use projected geographic points
define_legacy_grid(
pt_0_geo = c(720446.8, 4140492.5),
pt_0_grid = c(500, 500),
pt_1_geo = c(720361.2, 4140379.2),
pt_1_grid = c(360, 380),
geo_crs = 6341,
name = "Great New Grid"
)
#> Coordinate Reference System:
#> User input: +proj=omerc +lat_0=37.384999622921 +lonc=-108.509999731967 +alpha=-10.8146235871119 +gamma=0 +k_0=1.29877699316682 +x_0=500 +y_0=500
#> wkt:
#> PROJCRS["Great New Grid",
#> BASEGEOGCRS["Great New Grid",
#> DATUM["World Geodetic System 1984",
#> ELLIPSOID["WGS 84",6378137,298.257223563,
#> LENGTHUNIT["metre",1]],
#> ID["EPSG",6326]],
#> PRIMEM["Greenwich",0,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8901]]],
#> CONVERSION["Great New Grid",
#> METHOD["Hotine Oblique Mercator (variant B)",
#> ID["EPSG",9815]],
#> PARAMETER["Latitude of projection centre",37.384999622921,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8811]],
#> PARAMETER["Longitude of projection centre",-108.509999731967,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8812]],
#> PARAMETER["Azimuth of initial line",-10.8146235871119,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8813]],
#> PARAMETER["Angle from Rectified to Skew Grid",0,
#> ANGLEUNIT["degree",0.0174532925199433],
#> ID["EPSG",8814]],
#> PARAMETER["Scale factor on initial line",1.29877699316682,
#> SCALEUNIT["unity",1],
#> ID["EPSG",8815]],
#> PARAMETER["Easting at projection centre",500,
#> LENGTHUNIT["metre",1],
#> ID["EPSG",8816]],
#> PARAMETER["Northing at projection centre",500,
#> LENGTHUNIT["metre",1],
#> ID["EPSG",8817]]],
#> CS[Cartesian,2],
#> AXIS["(E)",east,
#> ORDER[1],
#> LENGTHUNIT["metre",1,
#> ID["EPSG",9001]]],
#> AXIS["(N)",north,
#> ORDER[2],
#> LENGTHUNIT["metre",1,
#> ID["EPSG",9001]]]]Please note that the localgrid project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.