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Add Column using ECQL expressions

KNIME Spatial Processing Nodes version 1.2.2.v201911131528 by EIFER (European Institute for Energy Research)

Add to WKT (Well-known Text) geometries a column computed using the Contextual Query Language

When your expression returns a numeric, Boolean or String result, you have to define the type of the column into which this results will be stored and the name of this column. If your expression returns a geometry, you can either process it as a geometry, and replace the original geometry; or store it as a String into a novel column.

Examples of queries:

  • compute the area: "area(the_geom)"
  • compute a centroid: "centroid(the_geom)"
  • compute a buffer: "buffer(the_geom, 10)"
  • compute the distance to a point defined by flow two Double flow variables x and y: "distance(the_geom,$${Dx}}$,$${Dy}}$)"
More examples can be found here: Geoserver ECQL Tutorial

Note that the units used in the query depend on the Coordinate Reference System.

The actual processing is done by the awesome geotools library.

Options

query
The query in Contextual Query Language
type
The type of the column to create. Ensure it is consistent with the result of the query
name
The name of the column to create

Input Ports

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Entities with spatial features

Output Ports

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The entities with the computation result

Best Friends (Incoming)

Best Friends (Outgoing)

Workflows

Installation

To use this node in KNIME, install KNIME Spatial Processing Nodes from the following update site:

KNIME 4.3

A zipped version of the software site can be downloaded here.

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