Validate Coords or Waypoints

Validate objects of class "coords" or "waypoints" as geographic locations.

Usage

validate(x, ...)

# S3 method for class 'coords'
validate(x, ..., force = TRUE)

# S3 method for class 'waypoints'
validate(x, ..., force = TRUE)

Arguments

x: object of class "coords" created by function as_coords(), or class "waypoints" created by function as_waypoints().
...: further arguments passed to or from other methods.
force: logical signifying whether, if TRUE, to perform full de novo revalidation or, if FALSE, simply check existing "valid" attribute in the case of a "coords" object, or "validlat" and "validlon" attributes in the case of a "waypoints" object and only revalidate if any of these are missing; default TRUE.

Value

validate() returns its argument with logical vector attribute "valid", or attributes "validlat" and "validlon" updated as appropriate for "coords" and' "waypoints" objects respectively.

Details

Individual coordinate values within "coords" or "waypoints" objects are checked to ensure they represent valid geographic locations.

To be valid, the absolute values of coordinates in degrees must not exceed 180°, or 90° if degrees of latitude and, similarly, the absolute values of the minutes and seconds components, where given, must not exceed 60. Otherwise, a warning will be issued and the "valid" attribute in the case of a "coords" object, or "validlat" and "validlon" attributes in the case of a "waypoints" object will be set to FALSE for any non-compliant coordinate values.

Argument force is primarily intended for use by the print() methods for classes "coords" and "waypoints" and should otherwise left as the default value TRUE.

Examples

## Continuing example from `as_coords()`...

## Validate "coords" object in degrees and minutes
validate(dm)
#> Nelson's Column                          51°30.4659′ N
#> Ostravice                                49°32.7726′ N
#> Tally Ho                                 48°06.4339′ N
#> Washington Monument                      38°53.3696′ N
#> Null Island                               0°00.0000′ N
#> Tristan da Cunha                         37°06.7044′ S
#> Mawson Peak                              53°06.2869′ S
#> Silvio Pettirossi International Airport  25°14.4093′ S
#> Nelson's Column                           0°07.6754′ W
#> Ostravice                                18°23.9137′ E
#> Tally Ho                                122°46.7203′ W
#> Washington Monument                      77°02.1145′ W
#> Null Island                               0°00.0000′ E
#> Tristan da Cunha                         12°17.3178′ W
#> Mawson Peak                              73°31.0370′ E
#> Silvio Pettirossi International Airport  57°31.1536′ W

## Deliberately change the first coordinate to a value greater
## than 60 minutes using the `[<-(<coords>)` replacement operator,
## which itself invokes `validate(dm)` -- see help(`[<-.coords`)
dm[1] <- 5160.4659
#> Warning: Invalid coords!

dm
#> Warning: Invalid coords!
#> Nelson's Column                          51°60.4659′ N
#> Ostravice                                49°32.7726′ N
#> Tally Ho                                 48°06.4339′ N
#> Washington Monument                      38°53.3696′ N
#> Null Island                               0°00.0000′ N
#> Tristan da Cunha                         37°06.7044′ S
#> Mawson Peak                              53°06.2869′ S
#> Silvio Pettirossi International Airport  25°14.4093′ S
#> Nelson's Column                           0°07.6754′ W
#> Ostravice                                18°23.9137′ E
#> Tally Ho                                122°46.7203′ W
#> Washington Monument                      77°02.1145′ W
#> Null Island                               0°00.0000′ E
#> Tristan da Cunha                         12°17.3178′ W
#> Mawson Peak                              73°31.0370′ E
#> Silvio Pettirossi International Airport  57°31.1536′ W

## Examine "valid" attribute of dm
attr(dm, "valid")
#>  [1] FALSE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE
#> [13]  TRUE  TRUE  TRUE  TRUE

###
## Continuing second example from `as_waypoints()`...

## Validate "waypoints" object in decimal degrees

validate(wp)
#>                                            Latitude     Longitude
#>                                          ___________  ____________
#> Nelson's Column                           51.507765°    -0.127924°
#> Ostravice                                 49.546210°    18.398562°
#> Tally Ho                                  48.107232°  -122.778671°
#> Washington Monument                       38.889494°   -77.035242°
#> Null Island                                0.000000°     0.000000°
#> Tristan da Cunha                         -37.111740°   -12.288630°
#> Mawson Peak                              -53.104781°    73.517283°
#> Silvio Pettirossi International Airport  -25.240156°   -57.519227°

## Deliberately change the penultimate latitude to an absolute
## value greater than 90 degrees, using the usual base package
## replacement `[<-` operator, which does not invoke `validate(dm)`
## -- we must do so ourselves
wp$lat[7] <- -93.104781

validate(wp)
#> Warning: Invalid latitude!
#> Warning: Invalid latitude!
#>                                            Latitude     Longitude
#>                                          ___________  ____________
#> Nelson's Column                           51.507765°    -0.127924°
#> Ostravice                                 49.546210°    18.398562°
#> Tally Ho                                  48.107232°  -122.778671°
#> Washington Monument                       38.889494°   -77.035242°
#> Null Island                                0.000000°     0.000000°
#> Tristan da Cunha                         -37.111740°   -12.288630°
#> Mawson Peak                              -93.104781°    73.517283°
#> Silvio Pettirossi International Airport  -25.240156°   -57.519227°

## Examine "validlat" attribute of wp
attr(wp, "validlat")
#> [1]  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE  TRUE

rm(dm, wp)

Usage

Arguments

Value

Details

See also

Examples