qgis_fieldcalculator: QGIS algorithm - Field calculator

In JanCaha/r_package_qgis: An extension of package "qgisprocess" providing direct R functions for QGIS functions

QGIS algorithm - Field calculator

Description

QGIS Algorithm provided by QGIS (native c++) Field calculator (native:fieldcalculator). This algorithm computes a new vector layer with the same features of the input layer, but either overwriting an existing attribute or adding an additional attribute. The values of this field are computed from each feature using an expression, based on the properties and attributes of the feature. Note that if "Field name" is an existing field in the layer then all the rest of the field settings are ignored.

Usage

qgis_fieldcalculator(
  INPUT = qgisprocess:::qgis_default_value(),
  FIELD_NAME = qgisprocess:::qgis_default_value(),
  FIELD_TYPE = qgisprocess:::qgis_default_value(),
  FIELD_LENGTH = qgisprocess:::qgis_default_value(),
  FIELD_PRECISION = qgisprocess:::qgis_default_value(),
  FORMULA = qgisprocess:::qgis_default_value(),
  OUTPUT = qgisprocess:::qgis_default_value(),
  ...,
  .complete_output = .complete_output_option(),
  .quiet = .quiet_option(),
  .messages = .message_option()
)

Arguments

INPUT	source - Input layer. Path to a vector layer.
FIELD_NAME	string - Field name. String value. field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field. expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression.
FIELD_TYPE	enum of ⁠("Decimal (double)", "Integer (32 bit)", "Text (string)", "Date", "Time", "Date & Time", "Boolean", "Binary Object (BLOB)", "String List", "Integer List", "Decimal (double) List")⁠ - Result field type. Number of selected option, e.g. '1'. Comma separated list of options, e.g. '1,3'.
FIELD_LENGTH	number - Result field length. A numeric value. field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field. expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression.
FIELD_PRECISION	number - Result field precision. A numeric value. field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field. expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression.
FORMULA	expression - Formula. A valid QGIS expression string, e.g "road_name" = 'MAIN RD'.
OUTPUT	sink - Calculated. Path for new vector layer.
...	further parameters passed to qgisprocess::qgis_run_algorithm()
.complete_output	logical specifying if complete out of qgisprocess::qgis_run_algorithm() should be used (TRUE) or first output (most likely the main) should read (FALSE). Default value is TRUE.
.quiet	logical specifying if parameter .quiet for qgisprocess::qgis_run_algorithm() Default value is TRUE.
.messages	logical specifying if messages from qgisprocess::qgis_run_algorithm() should be printed (TRUE) or not (FALSE). Default value is FALSE.

Details

Outputs description

• OUTPUT - outputVector - Calculated

JanCaha/r_package_qgis documentation built on Nov. 3, 2024, 5:25 p.m.