NCL Website header

Lat/lon functions

add90LatX Adds two fake pole points (90S and 90N) to the rightmost dimension of the given data.
add90LatY Adds two fake pole points (90S and 90N) to the leftmost dimension of the given data.
area_poly_sphere Calculates the area enclosed by an arbitrary polygon on the sphere.
bin_avg Calculates gridded binned averages and counts on a rectilinear grid using randomly spaced data.
bin_sum Calculates binned sums and counts over multiple invocations of the procedure on a rectilinear grid.
gaus Computes Gaussian latitudes and weights.
gaus_lobat Computes Gaussian latitudes and weights using Gauss-Lobatto quadrature.
gaus_lobat_wgt Computes Gauss-Lobatto weights given a one-dimensional array of Gauss-Lobatto latitudes.
gc_aangle Finds the acute angle between two great circles on the globe.
gc_clkwise Tests clockwise/counterclockwise ordering of points on spherical polygon.
gc_dangle Finds the directed angle between two great circles having a specified intersection point.
gc_inout Determines if a list of lat/lon specified points are inside or outside of spherical lat/lon polygon(s).
gc_latlon Finds the great circle distance (true surface distance) between two points on the globe and interpolates points along the great circle.
gc_onarc Determines if a point on the globe lies on a specified great circle arc.
gc_pnt2gc Finds the angular distance from a point to a great circle.
gc_qarea Finds the area of a quadrilateral patch on the unit sphere.
gc_tarea Finds the area of a triangular patch on the unit sphere.
getind_latlon2d Returns the indices (subscripts) of two-dimensional latitude/longitude arrays closest to a user-specified latitude/longitude coordinate pair.
landsea_mask Returns a grid that contains a land/sea mask given any latitude and longitude array.
latGau Generates gaussian latitudes and associated metadata.
latGauWgt Generates gaussian weights and associated metadata.
latGlobeF Generates latitudes and associated metadata for a global fixed grid.
latGlobeFo Generates latitudes and associated metadata for a global fixed offset grid.
latlon2utm Converts from lat/lon to UTM using a specified datum.
latRegWgt Generates [sin(lat+dlat/2)-sin(lat-dlat/2)] weights for equally spaced (regular) global grids that will sum to 2.0.
lonFlip Reorders a global rectilinear array about the central longitude coordinate variable.
lonGlobeF Generates longitudes and associated metadata for a global fixed grid.
lonGlobeFo Generates longitudes and associated metadata for a global fixed offset grid.
lonPivot Pivots an array about a user-specified longitude (rectilinear grids only).
nggcog Calculates the latitudes and longitudes of a set of points approximating a circle at a given point on the surface of the globe.
niceLatLon2D Check two-dimensional map coordinates to see if they have a "nice" structure.
NormCosWgtGlobe Create normalized cosine weights that sum to 2.0.
plt_pdfxy Creates a nice plot of the joint probability array created by the pdfxy function.
region_ind Returns the indices (subscripts) of two-dimensional latitude/longitude arrays that span user specified latitude/longitude boundaries.
utm2latlon Converts from UTM to lat/lon using a specified datum.
wrf_ij_to_ll Finds the nearest longitude, latitude locations to the specified model grid indices (i,j).
wrf_latlon_to_ij Finds the nearest model grid indices (i,j) to the specific location(s) in latitude and longitude (deprecated).
wrf_ll_to_ij Finds the nearest model grid indices (i,j) to the specified location(s) in longitude and latitude.
wrf_user_ij_to_ll Finds the nearest longitude, latitude locations to the specified model grid indices (i,j).
wrf_user_ll_to_ij Finds the nearest model grid indices (i,j) to the specified location(s) in longitude and latitude.