Package 'dggridR' reference manual

Title:	Discrete Global Grids
Description:	Spatial analyses involving binning require that every bin have the same area, but this is impossible using a rectangular grid laid over the Earth or over any projection of the Earth. Discrete global grids use hexagons, triangles, and diamonds to overcome this issue, overlaying the Earth with equally-sized bins. This package provides utilities for working with discrete global grids, along with utilities to aid in plotting such data.
Authors:	Richard Barnes [aut], Kevin Sahr [aut, cph], Gerald Evenden [cph], Angus Johnson [cph], Frank Warmerdam [cph], Even Rouault [cph], Lian Song [ctb], Sebastian Krantz [ctb, cre]
Maintainer:	Sebastian Krantz <[email protected]>
License:	AGPL (>= 3)
Version:	3.1.0
Built:	2024-10-30 06:46:39 UTC
Source:	https://github.com/SebKrantz/dggridR

Determine an appropriate grid resolution based on input data.

Description

This is a generic function that is used to determine an appropriate resolution given an area, cell spacing, or correlated length scale. It does so by extracting the appropriate length/area column and searching it for a value close to the input.

Usage

dg_closest_res(
  dggs,
  col,
  val,
  round = "nearest",
  show_info = TRUE,
  metric = TRUE
)
dg_closest_res(
  dggs,
  col,
  val,
  round = "nearest",
  show_info = TRUE,
  metric = TRUE
)

Arguments

`dggs`	A dggs object from dgconstruct()
`col`	Column in which to search for a close value. Should be: area_km, spacing_km, or cls_km.
`val`	The value to search for
`round`	What direction to search in. Must be nearest, up, or down.
`show_info`	Print the area, spacing, and CLS of the chosen resolution.
`metric`	Whether input and output should be in metric (TRUE) or imperial (FALSE)

Value

A number representing the grid resolution

Examples

library(dggridR)
dggs <- dgconstruct(res=20)
res  <- dg_closest_res(dggs,'area_km',1)
dggs <- dgsetres(dggs,res)
library(dggridR)
dggs <- dgconstruct(res=20)
res  <- dg_closest_res(dggs,'area_km',1)
dggs <- dgsetres(dggs,res)

Determine resolution based on desired area

Description

Determine an appropriate grid resolution based on a desired cell area.

Usage

dg_closest_res_to_area(
  dggs,
  area,
  round = "nearest",
  show_info = TRUE,
  metric = TRUE
)
dg_closest_res_to_area(
  dggs,
  area,
  round = "nearest",
  show_info = TRUE,
  metric = TRUE
)

Arguments

`dggs`	A dggs object from dgconstruct()
`area`	The desired area of the grid's cells
`round`	What direction to search in. Must be nearest, up, or down.
`show_info`	Print the area, spacing, and CLS of the chosen resolution.
`metric`	Whether input and output should be in metric (TRUE) or imperial (FALSE)

Value

A number representing the grid resolution

Examples

library(dggridR)
dggs <- dgconstruct(res=20)
res  <- dg_closest_res_to_area(dggs,1)
dggs <- dgsetres(dggs,res)
library(dggridR)
dggs <- dgconstruct(res=20)
res  <- dg_closest_res_to_area(dggs,1)
dggs <- dgsetres(dggs,res)

Determine an appropriate grid resolution based on a desired characteristic length scale of the cells.

Description

The characteristic length scale (CLS) is the diameter of a spherical cap of the same area as a cell of the specified resolution.

Usage

dg_closest_res_to_cls(
  dggs,
  cls,
  round = "nearest",
  show_info = TRUE,
  metric = TRUE
)
dg_closest_res_to_cls(
  dggs,
  cls,
  round = "nearest",
  show_info = TRUE,
  metric = TRUE
)

Arguments

`dggs`	A dggs object from dgconstruct()
`cls`	The desired CLS of the cells.
`round`	What direction to search in. Must be nearest, up, or down.
`show_info`	Print the area, spacing, and CLS of the chosen resolution.
`metric`	Whether input and output should be in metric (TRUE) or imperial (FALSE)

Value

A number representing the grid resolution

Examples

library(dggridR)
dggs <- dgconstruct(res=20)
res  <- dg_closest_res_to_cls(dggs,1)
dggs <- dgsetres(dggs,res)
library(dggridR)
dggs <- dgconstruct(res=20)
res  <- dg_closest_res_to_cls(dggs,1)
dggs <- dgsetres(dggs,res)

Determine grid resolution from desired spacing.

Description

Determine an appropriate grid resolution based on a desired spacing between the center of adjacent cells.

Usage

dg_closest_res_to_spacing(
  dggs,
  spacing,
  round = "nearest",
  show_info = TRUE,
  metric = TRUE
)
dg_closest_res_to_spacing(
  dggs,
  spacing,
  round = "nearest",
  show_info = TRUE,
  metric = TRUE
)

Arguments

`dggs`	A dggs object from dgconstruct()
`spacing`	The desired spacing between the center of adjacent cells
`round`	What direction to search in. Must be nearest, up, or down.
`show_info`	Print the area, spacing, and CLS of the chosen resolution.
`metric`	Whether input and output should be in metric (TRUE) or imperial (FALSE)

Value

A number representing the grid resolution

Examples

library(dggridR)
dggs <- dgconstruct(res=20)
res  <- dg_closest_res_to_spacing(dggs,1)
dggs <- dgsetres(dggs,res)
library(dggridR)
dggs <- dgconstruct(res=20)
res  <- dg_closest_res_to_spacing(dggs,1)
dggs <- dgsetres(dggs,res)

Control global aspects of the dggridR package

Description

This environment is used to control global features of the dggridR package. At the moment the only option is 'dg_debug' which, when set to TRUE provides extensive outputs useful for tracking down bugs.

Usage

dg_env
dg_env

Format

An object of class environment of length 1.

Load a KML file

Description

Convert data from internal dggrid functions into something useful: an sp object or a data frame

Usage

dg_process_polydata(polydata)
dg_process_polydata(polydata)

Arguments

polydata

Polygons generated by dggrid. These will be converted.

Value

Returns an sf object.

National border of South Africa

Description

This variable points to a shapefile containing the national border of South Africa

Usage

dg_shpfname_south_africa()
dg_shpfname_south_africa()

Value

A filename of a shapefile containing the national border of South Africa

Return boundary coordinates for specified cells

Description

Returns the coordinates constituting the boundary of a specified set of cells. Duplicates are eliminated to reduce processing and storage requirements.

Usage

dgcellstogrid(dggs, cells, savegrid = NA, return_sf = TRUE)
dgcellstogrid(dggs, cells, savegrid = NA, return_sf = TRUE)

Arguments

`dggs`	A dggs object from dgconstruct()
`cells`	The cells to get the boundaries of
`savegrid`	If savegrid is set to a file path, then a shapefile containing the grid is written to that path and the filename is returned. No other manipulations are done. Default: NA (do not save grid, return it)
`return_sf`	logical. If `FALSE`, a long-format data frame giving the coordinates of the vertices of each cell is returned. This is is considerably faster and more memory efficient than creating an sf data frame.

Value

Returns an sf object. If !is.na(savegrid), returns a filename.

Examples

library(dggridR)
data(dgquakes)

#Construct a grid with cells about ~1000 miles wide
dggs          <- dgconstruct(spacing=1000,metric=FALSE)
dgquakes$cell <- dgGEO_to_SEQNUM(dggs,dgquakes$lat,dgquakes$lon)$seqnum

#Get grid cells for the earthquakes identified
grid          <- dgcellstogrid(dggs, dgquakes$cell)
library(dggridR)
data(dgquakes)

#Construct a grid with cells about ~1000 miles wide
dggs          <- dgconstruct(spacing=1000,metric=FALSE)
dgquakes$cell <- dgGEO_to_SEQNUM(dggs,dgquakes$lat,dgquakes$lon)$seqnum

#Get grid cells for the earthquakes identified
grid          <- dgcellstogrid(dggs, dgquakes$cell)

Construct a discrete global grid system (dggs) object

Description

Construct a discrete global grid system (dggs) object

Usage

dgconstruct(
  projection = "ISEA",
  aperture = 3,
  topology = "HEXAGON",
  res = NA,
  precision = 7,
  area = NA,
  spacing = NA,
  cls = NA,
  resround = "nearest",
  metric = TRUE,
  show_info = TRUE,
  azimuth_deg = 0,
  pole_lat_deg = 58.28252559,
  pole_lon_deg = 11.25
)
dgconstruct(
  projection = "ISEA",
  aperture = 3,
  topology = "HEXAGON",
  res = NA,
  precision = 7,
  area = NA,
  spacing = NA,
  cls = NA,
  resround = "nearest",
  metric = TRUE,
  show_info = TRUE,
  azimuth_deg = 0,
  pole_lat_deg = 58.28252559,
  pole_lon_deg = 11.25
)

Arguments

`projection`	Type of grid to use. Options are: ISEA and FULLER. Default: ISEA3H
`aperture`	How finely subsequent resolution levels divide the grid. Options are: 3, 4. Not all options work with all projections and topologies. Default: 3
`topology`	Shape of cell. Options are: HEXAGON, DIAMOND, TRIANGLE. Default: HEXAGON
`res`	Resolution. Must be in the range [0,30]. Larger values represent finer resolutions. Appropriate resolutions can be found with dg_closest_res_to_area(), dg_closest_res_to_spacing(), and dg_closest_res_to_cls(). Default is 9, which corresponds to a cell area of ~2600 sq km and a cell spacing of ~50 km. Only one of res, area, length, or cls should be used.
`precision`	Round output to this number of decimal places. Must be in the range [0,30]. Default: 7.
`area`	The desired area of the grid's cells. Only one of res, area, length, or cls should be used.
`spacing`	The desired spacing between the center of adjacent cells. Only one of res, area, length, or cls should be used.
`cls`	The desired CLS of the cells. Only one of res, area, length, or cls should be used.
`resround`	What direction to search in. Must be nearest, up, or down.
`metric`	Whether input and output should be in metric (TRUE) or imperial (FALSE)
`show_info`	Print the area, spacing, and CLS of the chosen resolution.
`azimuth_deg`	Rotation in degrees of grid about its pole, value in [0,360]. Default=0.
`pole_lat_deg`	Latitude in degrees of the pole, value in [-90,90]. Default=58.28252559.
`pole_lon_deg`	Longitude in degrees of the pole, value in [-180,180]. Default=11.25.

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

library(dggridR)
dggs <- dgconstruct(res=20)

dggs <- dgconstruct(area=5,metric=FALSE)
library(dggridR)
dggs <- dgconstruct(res=20)

dggs <- dgconstruct(area=5,metric=FALSE)

Return the coordinates constituting the boundary of cells for the entire Earth

Description

Note: If you have a high-resolution grid this may take a very long time to execute.

Usage

dgearthgrid(dggs, savegrid = NA, return_sf = TRUE)
dgearthgrid(dggs, savegrid = NA, return_sf = TRUE)

Arguments

`dggs`	A dggs object from dgconstruct().
`savegrid`	If savegrid is set to a file path, then a shapefile containing the grid is written to that path and the filename is returned. No other manipulations are done. Default: NA (do not save grid, return it)
`return_sf`	logical. If `FALSE`, a long-format data frame giving the coordinates of the vertices of each cell is returned. This is is considerably faster and more memory efficient than creating an sf data frame.

Value

Returns an sf object. If !is.na(savegrid), returns a filename.

Examples


library(dggridR)
dggs         <- dgconstruct(res=20)
res          <- dg_closest_res_to_spacing(dggs,spacing=1000,round='down',metric=FALSE)
dggs         <- dgsetres(dggs,res)
gridfilename <- dgearthgrid(dggs,savegrid=tempfile(fileext=".shp")) #Save directly to a file

library(dggridR)
dggs         <- dgconstruct(res=20)
res          <- dg_closest_res_to_spacing(dggs,spacing=1000,round='down',metric=FALSE)
dggs         <- dgsetres(dggs,res)
gridfilename <- dgearthgrid(dggs,savegrid=tempfile(fileext=".shp")) #Save directly to a file

Convert from GEO to GEO

Description

Uses a discrete global grid system to convert between GEO and GEO (see vignette for details)

Usage

dgGEO_to_GEO(dggs, in_lon_deg, in_lat_deg)
dgGEO_to_GEO(dggs, in_lon_deg, in_lat_deg)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_lon_deg`	Vector of longitude, in degrees
`in_lat_deg`	Vector of latitude, in degrees

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_GEO(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_GEO(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

Convert from GEO to PLANE

Description

Uses a discrete global grid system to convert between GEO and PLANE (see vignette for details)

Usage

dgGEO_to_PLANE(dggs, in_lon_deg, in_lat_deg)
dgGEO_to_PLANE(dggs, in_lon_deg, in_lat_deg)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_lon_deg`	Vector of longitude, in degrees
`in_lat_deg`	Vector of latitude, in degrees

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_PLANE(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_PLANE(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

Convert from GEO to PROJTRI

Description

Uses a discrete global grid system to convert between GEO and PROJTRI (see vignette for details)

Usage

dgGEO_to_PROJTRI(dggs, in_lon_deg, in_lat_deg)
dgGEO_to_PROJTRI(dggs, in_lon_deg, in_lat_deg)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_lon_deg`	Vector of longitude, in degrees
`in_lat_deg`	Vector of latitude, in degrees

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_PROJTRI(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_PROJTRI(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

Convert from GEO to Q2DD

Description

Uses a discrete global grid system to convert between GEO and Q2DD (see vignette for details)

Usage

dgGEO_to_Q2DD(dggs, in_lon_deg, in_lat_deg)
dgGEO_to_Q2DD(dggs, in_lon_deg, in_lat_deg)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_lon_deg`	Vector of longitude, in degrees
`in_lat_deg`	Vector of latitude, in degrees

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_Q2DD(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_Q2DD(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

Convert from GEO to Q2DI

Description

Uses a discrete global grid system to convert between GEO and Q2DI (see vignette for details)

Usage

dgGEO_to_Q2DI(dggs, in_lon_deg, in_lat_deg)
dgGEO_to_Q2DI(dggs, in_lon_deg, in_lat_deg)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_lon_deg`	Vector of longitude, in degrees
`in_lat_deg`	Vector of latitude, in degrees

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_Q2DI(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_Q2DI(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

Convert from GEO to SEQNUM

Description

Uses a discrete global grid system to convert between GEO and SEQNUM (see vignette for details)

Usage

dgGEO_to_SEQNUM(dggs, in_lon_deg, in_lat_deg)
dgGEO_to_SEQNUM(dggs, in_lon_deg, in_lat_deg)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_lon_deg`	Vector of longitude, in degrees
`in_lat_deg`	Vector of latitude, in degrees

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_SEQNUM(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgGEO_to_SEQNUM(dggs, in_lon_deg, in_lat_deg)

## End(Not run)

Get table of grid resolution information

Description

Gets a grid's resolution and cell property info as a data frame.

Usage

dggetres(dggs)
dggetres(dggs)

Arguments

dggs

A dggs object from dgconstruct()

Value

A data frame containing the resolution levels, number of cells, area of those cells, intercell spacing, and characteristic length scale of the cells. All values are in kilometres.

Examples

library(dggridR)
dggs <- dgconstruct(res=20)
dggetres(dggs)
library(dggridR)
dggs <- dgconstruct(res=20)
dggetres(dggs)

Print info about a dggs object to the screen

Description

dggs objects have many settings. This returns all of them, along with info about the grid being specified.

Usage

dginfo(dggs)
dginfo(dggs)

Arguments

dggs

A dggs object from dgconstruct()

Value

No return. All info is printed to the screen.

Examples

library(dggridR)
dggs <- dgconstruct(res=20)
dginfo(dggs)
library(dggridR)
dggs <- dgconstruct(res=20)
dginfo(dggs)

Get largest cell id for a dggs

Description

Cells are labeled 1-N. This function returns N. This is useful if you want to choose cells from the dggs randomly.

Usage

dgmaxcell(dggs, res = NA)
dgmaxcell(dggs, res = NA)

Arguments

`dggs`	A dggs object from dgconstruct()
`res`	If NA, use the resolution specified by the dggs. Otherwise, override the resolution.

Value

The maximum cell id.

Examples

#Choose a set of cells randomly distributed over the Earth
library(dggridR)
dggs    <- dgconstruct(spacing=1000, metric=FALSE, resround='down')
N       <- 100                                 #Number of cells
maxcell <- dgmaxcell(dggs)                     #Get maximum cell id
cells   <- sample(1:maxcell, N, replace=FALSE) #Choose random cells
grid    <- dgcellstogrid(dggs,cells) #Get grid
#Choose a set of cells randomly distributed over the Earth
library(dggridR)
dggs    <- dgconstruct(spacing=1000, metric=FALSE, resround='down')
N       <- 100                                 #Number of cells
maxcell <- dgmaxcell(dggs)                     #Get maximum cell id
cells   <- sample(1:maxcell, N, replace=FALSE) #Choose random cells
grid    <- dgcellstogrid(dggs,cells) #Get grid

Convert from PROJTRI to GEO

Description

Uses a discrete global grid system to convert between PROJTRI and GEO (see vignette for details)

Usage

dgPROJTRI_to_GEO(dggs, in_tnum, in_tx, in_ty)
dgPROJTRI_to_GEO(dggs, in_tnum, in_tx, in_ty)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_tnum`	Vector of triangle numbers
`in_tx`	Vector of triangle x values
`in_ty`	Vector of triangle y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_GEO(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_GEO(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

Convert from PROJTRI to PLANE

Description

Uses a discrete global grid system to convert between PROJTRI and PLANE (see vignette for details)

Usage

dgPROJTRI_to_PLANE(dggs, in_tnum, in_tx, in_ty)
dgPROJTRI_to_PLANE(dggs, in_tnum, in_tx, in_ty)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_tnum`	Vector of triangle numbers
`in_tx`	Vector of triangle x values
`in_ty`	Vector of triangle y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_PLANE(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_PLANE(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

Convert from PROJTRI to PROJTRI

Description

Uses a discrete global grid system to convert between PROJTRI and PROJTRI (see vignette for details)

Usage

dgPROJTRI_to_PROJTRI(dggs, in_tnum, in_tx, in_ty)
dgPROJTRI_to_PROJTRI(dggs, in_tnum, in_tx, in_ty)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_tnum`	Vector of triangle numbers
`in_tx`	Vector of triangle x values
`in_ty`	Vector of triangle y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_PROJTRI(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_PROJTRI(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

Convert from PROJTRI to Q2DD

Description

Uses a discrete global grid system to convert between PROJTRI and Q2DD (see vignette for details)

Usage

dgPROJTRI_to_Q2DD(dggs, in_tnum, in_tx, in_ty)
dgPROJTRI_to_Q2DD(dggs, in_tnum, in_tx, in_ty)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_tnum`	Vector of triangle numbers
`in_tx`	Vector of triangle x values
`in_ty`	Vector of triangle y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_Q2DD(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_Q2DD(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

Convert from PROJTRI to Q2DI

Description

Uses a discrete global grid system to convert between PROJTRI and Q2DI (see vignette for details)

Usage

dgPROJTRI_to_Q2DI(dggs, in_tnum, in_tx, in_ty)
dgPROJTRI_to_Q2DI(dggs, in_tnum, in_tx, in_ty)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_tnum`	Vector of triangle numbers
`in_tx`	Vector of triangle x values
`in_ty`	Vector of triangle y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_Q2DI(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_Q2DI(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

Convert from PROJTRI to SEQNUM

Description

Uses a discrete global grid system to convert between PROJTRI and SEQNUM (see vignette for details)

Usage

dgPROJTRI_to_SEQNUM(dggs, in_tnum, in_tx, in_ty)
dgPROJTRI_to_SEQNUM(dggs, in_tnum, in_tx, in_ty)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_tnum`	Vector of triangle numbers
`in_tx`	Vector of triangle x values
`in_ty`	Vector of triangle y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_SEQNUM(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgPROJTRI_to_SEQNUM(dggs, in_tnum, in_tx, in_ty)

## End(Not run)

Convert from Q2DD to GEO

Description

Uses a discrete global grid system to convert between Q2DD and GEO (see vignette for details)

Usage

dgQ2DD_to_GEO(dggs, in_quad, in_qx, in_qy)
dgQ2DD_to_GEO(dggs, in_quad, in_qx, in_qy)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_qx`	Vector of quadrant x values
`in_qy`	Vector of quadrant y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_GEO(dggs, in_quad, in_qx, in_qy)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_GEO(dggs, in_quad, in_qx, in_qy)

## End(Not run)

Convert from Q2DD to PLANE

Description

Uses a discrete global grid system to convert between Q2DD and PLANE (see vignette for details)

Usage

dgQ2DD_to_PLANE(dggs, in_quad, in_qx, in_qy)
dgQ2DD_to_PLANE(dggs, in_quad, in_qx, in_qy)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_qx`	Vector of quadrant x values
`in_qy`	Vector of quadrant y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_PLANE(dggs, in_quad, in_qx, in_qy)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_PLANE(dggs, in_quad, in_qx, in_qy)

## End(Not run)

Convert from Q2DD to PROJTRI

Description

Uses a discrete global grid system to convert between Q2DD and PROJTRI (see vignette for details)

Usage

dgQ2DD_to_PROJTRI(dggs, in_quad, in_qx, in_qy)
dgQ2DD_to_PROJTRI(dggs, in_quad, in_qx, in_qy)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_qx`	Vector of quadrant x values
`in_qy`	Vector of quadrant y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_PROJTRI(dggs, in_quad, in_qx, in_qy)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_PROJTRI(dggs, in_quad, in_qx, in_qy)

## End(Not run)

Convert from Q2DD to Q2DD

Description

Uses a discrete global grid system to convert between Q2DD and Q2DD (see vignette for details)

Usage

dgQ2DD_to_Q2DD(dggs, in_quad, in_qx, in_qy)
dgQ2DD_to_Q2DD(dggs, in_quad, in_qx, in_qy)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_qx`	Vector of quadrant x values
`in_qy`	Vector of quadrant y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_Q2DD(dggs, in_quad, in_qx, in_qy)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_Q2DD(dggs, in_quad, in_qx, in_qy)

## End(Not run)

Convert from Q2DD to Q2DI

Description

Uses a discrete global grid system to convert between Q2DD and Q2DI (see vignette for details)

Usage

dgQ2DD_to_Q2DI(dggs, in_quad, in_qx, in_qy)
dgQ2DD_to_Q2DI(dggs, in_quad, in_qx, in_qy)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_qx`	Vector of quadrant x values
`in_qy`	Vector of quadrant y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_Q2DI(dggs, in_quad, in_qx, in_qy)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_Q2DI(dggs, in_quad, in_qx, in_qy)

## End(Not run)

Convert from Q2DD to SEQNUM

Description

Uses a discrete global grid system to convert between Q2DD and SEQNUM (see vignette for details)

Usage

dgQ2DD_to_SEQNUM(dggs, in_quad, in_qx, in_qy)
dgQ2DD_to_SEQNUM(dggs, in_quad, in_qx, in_qy)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_qx`	Vector of quadrant x values
`in_qy`	Vector of quadrant y values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_SEQNUM(dggs, in_quad, in_qx, in_qy)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DD_to_SEQNUM(dggs, in_quad, in_qx, in_qy)

## End(Not run)

Convert from Q2DI to GEO

Description

Uses a discrete global grid system to convert between Q2DI and GEO (see vignette for details)

Usage

dgQ2DI_to_GEO(dggs, in_quad, in_i, in_j)
dgQ2DI_to_GEO(dggs, in_quad, in_i, in_j)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_i`	Vector of quadrant i values
`in_j`	Vector of quadrant j values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_GEO(dggs, in_quad, in_i, in_j)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_GEO(dggs, in_quad, in_i, in_j)

## End(Not run)

Convert from Q2DI to PLANE

Description

Uses a discrete global grid system to convert between Q2DI and PLANE (see vignette for details)

Usage

dgQ2DI_to_PLANE(dggs, in_quad, in_i, in_j)
dgQ2DI_to_PLANE(dggs, in_quad, in_i, in_j)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_i`	Vector of quadrant i values
`in_j`	Vector of quadrant j values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_PLANE(dggs, in_quad, in_i, in_j)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_PLANE(dggs, in_quad, in_i, in_j)

## End(Not run)

Convert from Q2DI to PROJTRI

Description

Uses a discrete global grid system to convert between Q2DI and PROJTRI (see vignette for details)

Usage

dgQ2DI_to_PROJTRI(dggs, in_quad, in_i, in_j)
dgQ2DI_to_PROJTRI(dggs, in_quad, in_i, in_j)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_i`	Vector of quadrant i values
`in_j`	Vector of quadrant j values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_PROJTRI(dggs, in_quad, in_i, in_j)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_PROJTRI(dggs, in_quad, in_i, in_j)

## End(Not run)

Convert from Q2DI to Q2DD

Description

Uses a discrete global grid system to convert between Q2DI and Q2DD (see vignette for details)

Usage

dgQ2DI_to_Q2DD(dggs, in_quad, in_i, in_j)
dgQ2DI_to_Q2DD(dggs, in_quad, in_i, in_j)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_i`	Vector of quadrant i values
`in_j`	Vector of quadrant j values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_Q2DD(dggs, in_quad, in_i, in_j)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_Q2DD(dggs, in_quad, in_i, in_j)

## End(Not run)

Convert from Q2DI to Q2DI

Description

Uses a discrete global grid system to convert between Q2DI and Q2DI (see vignette for details)

Usage

dgQ2DI_to_Q2DI(dggs, in_quad, in_i, in_j)
dgQ2DI_to_Q2DI(dggs, in_quad, in_i, in_j)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_i`	Vector of quadrant i values
`in_j`	Vector of quadrant j values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_Q2DI(dggs, in_quad, in_i, in_j)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_Q2DI(dggs, in_quad, in_i, in_j)

## End(Not run)

Convert from Q2DI to SEQNUM

Description

Uses a discrete global grid system to convert between Q2DI and SEQNUM (see vignette for details)

Usage

dgQ2DI_to_SEQNUM(dggs, in_quad, in_i, in_j)
dgQ2DI_to_SEQNUM(dggs, in_quad, in_i, in_j)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_quad`	Vector of quad numbers
`in_i`	Vector of quadrant i values
`in_j`	Vector of quadrant j values

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_SEQNUM(dggs, in_quad, in_i, in_j)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgQ2DI_to_SEQNUM(dggs, in_quad, in_i, in_j)

## End(Not run)

All earthquakes with magnitude >=3.0 earthquakes for 2015

Description

A data frame with 19914 observations on the following 4 variables.

time: Time of the quake. Example: 2015-12-31T23:39:28.940Z
lat: Latitude of the epicenter. Example: -7.0711
lon: Longitude of the epicenter. Example: -173.5178
mag: Magnitude of the quake. Example: 3.2

Usage

data(dgquakes)data(dgquakes)

Format

data frame

Source

The USGS Earthquake Hazards Program (https://earthquake.usgs.gov/earthquakes/search/).

Return the coordinates constituting the boundary of cells within a specified region

Description

Note: This may generate odd results for very large rectangles, because putting rectangles on spheres is weird... as you should know, if you're using this package.

Usage

dgrectgrid(
  dggs,
  minlat = -1,
  minlon = -1,
  maxlat = -1,
  maxlon = -1,
  cellsize = 0.1,
  ...
)
dgrectgrid(
  dggs,
  minlat = -1,
  minlon = -1,
  maxlat = -1,
  maxlon = -1,
  cellsize = 0.1,
  ...
)

Arguments

`dggs`	A dggs object from dgconstruct()
`minlat`	Minimum latitude of region of interest
`minlon`	Minimum longitude of region of interest
`maxlat`	Maximum latitude of region of interest
`maxlon`	Maximum longitude of region of interest
`cellsize`	Distance, in degrees, between the sample points used to generate the grid. Small values yield long generation times while large values may omit cells.
`...`	Further arguments passed to `dgcellstogrid`.

Value

Returns an sf object. If !is.na(savegrid), returns a filename.

Examples

library(dggridR)
dggs <- dgconstruct(spacing=1000,metric=FALSE,resround='down')

#Get grid cells for the conterminous United States
grid <- dgrectgrid(dggs,
               minlat=24.7433195, minlon=-124.7844079,
               maxlat=49.3457868, maxlon=-66.9513812)
library(dggridR)
dggs <- dgconstruct(spacing=1000,metric=FALSE,resround='down')

#Get grid cells for the conterminous United States
grid <- dgrectgrid(dggs,
               minlat=24.7433195, minlon=-124.7844079,
               maxlat=49.3457868, maxlon=-66.9513812)

Saves a generated grid to a shapefile

Description

Saves a generated grid to a shapefile

Usage

dgsavegrid(grid, shpfname)
dgsavegrid(grid, shpfname)

Arguments

`grid`	Grid to be saved
`shpfname`	File to save the grid to

Value

The filename the grid was saved to

Convert from SEQNUM to GEO

Description

Uses a discrete global grid system to convert between SEQNUM and GEO (see vignette for details)

Usage

dgSEQNUM_to_GEO(dggs, in_seqnum)
dgSEQNUM_to_GEO(dggs, in_seqnum)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_seqnum`	Globally unique number identifying the surface polygon

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_GEO(dggs, in_seqnum)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_GEO(dggs, in_seqnum)

## End(Not run)

Convert from SEQNUM to PLANE

Description

Uses a discrete global grid system to convert between SEQNUM and PLANE (see vignette for details)

Usage

dgSEQNUM_to_PLANE(dggs, in_seqnum)
dgSEQNUM_to_PLANE(dggs, in_seqnum)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_seqnum`	Globally unique number identifying the surface polygon

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_PLANE(dggs, in_seqnum)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_PLANE(dggs, in_seqnum)

## End(Not run)

Convert from SEQNUM to PROJTRI

Description

Uses a discrete global grid system to convert between SEQNUM and PROJTRI (see vignette for details)

Usage

dgSEQNUM_to_PROJTRI(dggs, in_seqnum)
dgSEQNUM_to_PROJTRI(dggs, in_seqnum)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_seqnum`	Globally unique number identifying the surface polygon

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_PROJTRI(dggs, in_seqnum)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_PROJTRI(dggs, in_seqnum)

## End(Not run)

Convert from SEQNUM to Q2DD

Description

Uses a discrete global grid system to convert between SEQNUM and Q2DD (see vignette for details)

Usage

dgSEQNUM_to_Q2DD(dggs, in_seqnum)
dgSEQNUM_to_Q2DD(dggs, in_seqnum)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_seqnum`	Globally unique number identifying the surface polygon

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_Q2DD(dggs, in_seqnum)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_Q2DD(dggs, in_seqnum)

## End(Not run)

Convert from SEQNUM to Q2DI

Description

Uses a discrete global grid system to convert between SEQNUM and Q2DI (see vignette for details)

Usage

dgSEQNUM_to_Q2DI(dggs, in_seqnum)
dgSEQNUM_to_Q2DI(dggs, in_seqnum)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_seqnum`	Globally unique number identifying the surface polygon

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_Q2DI(dggs, in_seqnum)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_Q2DI(dggs, in_seqnum)

## End(Not run)

Convert from SEQNUM to SEQNUM

Description

Uses a discrete global grid system to convert between SEQNUM and SEQNUM (see vignette for details)

Usage

dgSEQNUM_to_SEQNUM(dggs, in_seqnum)
dgSEQNUM_to_SEQNUM(dggs, in_seqnum)

Arguments

`dggs`	A dggs object from dgconstruct()
`in_seqnum`	Globally unique number identifying the surface polygon

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_SEQNUM(dggs, in_seqnum)

## End(Not run)

## Not run: 
library(dggridR)
dggs <- dgconstruct(res=20)

dgSEQNUM_to_SEQNUM(dggs, in_seqnum)

## End(Not run)

Set the resolution of a dggs object

Description

Set the resolution of a dggs object

Usage

dgsetres(dggs, res)
dgsetres(dggs, res)

Arguments

`dggs`	A dggs object from dgconstruct().
`res`	Resolution. Must be in the range [0,30]. Larger values represent finer resolutions. Appropriate resolutions can be found with dg_closest_res_to_area(), dg_closest_res_to_spacing(), and dg_closest_res_to_cls(). Default is 9, which corresponds to a cell area of ~2600 sq km and a cell spacing of ~50 km. Default: 9.

Value

Returns a dggs object which can be passed to other dggridR functions

Examples

library(dggridR)
dggs <- dgconstruct(res=20)
dggs <- dgsetres(dggs,10)
library(dggridR)
dggs <- dgconstruct(res=20)
dggs <- dgsetres(dggs,10)

Return boundary coordinates for cells intersecting a shapefile

Description

Returns the coordinates constituting the boundary of a set of cells which intersect or are contained by a polygon (or polygons) specified in a shapefile. Note that grid cells are also generated for holes in the shapefile's polygon(s).

Note that coordinates in the shapefile must be rounded to check polygon intersections. Currently this round preserves eight decimal digits of precision.

The eighth decimal place is worth up to 1.1 mm of precision: this is good for charting the motions of tectonic plates and the movements of volcanoes. Permanent, corrected, constantly-running GPS base stations might be able to achieve this level of accuracy.

In other words: you should be just fine with this level of precision.

Usage

dgshptogrid(dggs, shpfname, cellsize = 0.1, ...)
dgshptogrid(dggs, shpfname, cellsize = 0.1, ...)

Arguments

`dggs`	A dggs object from dgconstruct()
`shpfname`	Either a sf data frame or the file name of the shapefile. Filename should end with '.shp'.
`cellsize`	Distance, in degrees, between the sample points used to generate the grid. Small values yield long generation times while large values may omit cells.
`...`	Further arguments passed to `dgcellstogrid`.

Value

Returns an sf object. If !is.na(savegrid), returns a filename.

Examples

## Not run: 
library(dggridR)

dggs <- dgconstruct(spacing=25, metric=FALSE, resround='nearest')
south_africa_grid <- dgshptogrid(dggs,dg_shpfname_south_africa())

## End(Not run)
## Not run: 
library(dggridR)

dggs <- dgconstruct(spacing=25, metric=FALSE, resround='nearest')
south_africa_grid <- dgshptogrid(dggs,dg_shpfname_south_africa())

## End(Not run)

Verify that a dggs object has appropriate values

Description

Verify that a dggs object has appropriate values

Usage

dgverify(dggs)
dgverify(dggs)

Arguments

dggs

The dggs object to be verified

Value

The function has no return value. A stop signal is raised if the object is misspecified

Examples

library(dggridR)
dggs <- dgconstruct(res=20)
dgverify(dggs)
library(dggridR)
dggs <- dgconstruct(res=20)
dgverify(dggs)

Package 'dggridR'

Help Index

Determine an appropriate grid resolution based on input data.

Description

Usage

Arguments

Value

Examples

Determine resolution based on desired area

Description

Usage

Arguments

Value

Examples

Determine an appropriate grid resolution based on a desired characteristic length scale of the cells.

Description

Usage

Arguments

Value

Examples

Determine grid resolution from desired spacing.

Description

Usage

Arguments

Value

Examples

Control global aspects of the dggridR package

Description

Usage

Format

Load a KML file

Description

Usage

Arguments

Value

National border of South Africa

Description

Usage

Value

Return boundary coordinates for specified cells

Description

Usage

Arguments

Value

Examples

Construct a discrete global grid system (dggs) object

Description

Usage

Arguments

Value

Examples

Return the coordinates constituting the boundary of cells for the entire Earth

Description

Usage

Arguments

Value

Examples

Convert from GEO to GEO

Description

Usage

Arguments

Value

Examples

Convert from GEO to PLANE

Description

Usage

Arguments

Value

Examples

Convert from GEO to PROJTRI

Description

Usage

Arguments

Value

Examples

Convert from GEO to Q2DD

Description

Usage

Arguments

Value