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Create point geometry for ATTAINS Assessment Units

Source: R/GeospatialFunctions.R
TADA_CreatePointAUGeometry.Rd

Creates point or multipoint geometry for ATTAINS Assessment Units using ATTAINS.AssessmentUnitIdentifier when available, otherwise TADA.MonitoringLocationIdentifier.

Usage

TADA_CreatePointAUGeometry(
  .data,
  target_crs = 4269,
  download_geo = FALSE,
  auid_prefix = NULL
)

Arguments

.data

A data frame containing:

  • TADA.LongitudeMeasure

  • TADA.LatitudeMeasure

  • HorizontalCoordinateReferenceSystemDatumName

And at least one of:

  • ATTAINS.AssessmentUnitIdentifier

  • TADA.MonitoringLocationIdentifier

target_crs

Numeric. Target EPSG code for the output CRS. If the input geometry is not the same as the target_crs, it is transformed to the target_crs. Default is 4269. If the input CRS and target_crs match, no CRS transformation occurs.

download_geo

Logical. If TRUE, write a shapefile to the user's Downloads folder.

auid_prefix

Character or NULL. If provided and non-empty, this prefix is applied only to newly created ATTAINS.AssessmentUnitIdentifier values when missing or blank.

Value

An sf containing:

  • ATTAINS.AssessmentUnitIdentifier

  • HorizontalCoordinateReferenceSystemDatumName

  • epsg

  • geometry

If download_geo = TRUE, a shapefile is written to the Downloads folder.

Details

  • Missing or blank ATTAINS.AssessmentUnitIdentifier values are replaced with TADA.MonitoringLocationIdentifier.

  • Duplicate coordinate rows are removed before geometry creation.

  • Input coordinates are assumed to be in EPSG:4269 before transformation.

  • Single-location groups retain POINT geometry.

  • Multi-location groups are written as MULTIPOINT.

See also

TADA_CreatePointAUs()

Examples

if (FALSE) { # \dontrun{
# Example 1: Build point geometry from package data
# The input must include longitude, latitude, datum, and at least one ID field.
df <- Data_TribalNations_Harmonized |>
  dplyr::filter(OrganizationFormalName == "Blackfeet Nation (Montana)")

au_points <- TADA_CreatePointAUGeometry(df)
unique(sf::st_geometry_type(au_points))

# Example 2: Demonstrate POINT vs MULTIPOINT output
# AU1 has two locations, so it becomes MULTIPOINT.
# AU2 has one location, so it remains POINT.
df2 <- data.frame(
  ATTAINS.AssessmentUnitIdentifier = c("AU1", "AU1", "AU2"),
  TADA.MonitoringLocationIdentifier = c("ML1", "ML1", "ML2"),
  TADA.LongitudeMeasure = c(-90, -90, -91),
  TADA.LatitudeMeasure = c(40, 41, 41),
  HorizontalCoordinateReferenceSystemDatumName = c("NAD83", "NAD83", "NAD83"),
  stringsAsFactors = FALSE
)

au_geoms <- TADA_CreatePointAUGeometry(df2)
unique(sf::st_geometry_type(au_geoms))
} # }