aRTlayer {aRT} | R Documentation

## Class aRTlayer

### Description

Class that represents a layer of information in the database. It can insert geometries into the database, process them and create/open `aRTtable`, `aRTtheme` and `aRTquerier` objects. TerraLib layers can stores various geometries in a layer, but in aRT, for simplify, each layer stores only one type of geometry.

### Objects from the Class

Objects can be created by calls of the form `new("aRTlayer", aRTdb, layername, proj)`. Examples:
`obj = new("aRTlayer", aRTdb, layername, create=T)`
`obj = new("aRTlayer",db,l="llatlong",proj="+proj=latlong +datum=NAD83",c=T)`

To avoid creating objects this way, there are two functions of class `aRTdb`: `createLayer` and `openLayer`.

### Arguments

aRTdb
  Object of aRTdb class.
layername
  Name of the layer.
proj
  Projection in proj.4 format. Some projections are not supported by TerraLib.
create
  Can the layer be created if it does not exist?

### Extends

Class `aRTcomponent`, directly.

### Methods

addLines:
  Insert lines in the layer.
addPoints:
  Insert points in the layer.
addPolygons:
  Insert polygons (rings) in the layer.
createTheme:
  Create a new theme and returns it.
getAttributes:
  Return the stored attributes.
getGeometry:
  Return the geometries stored in the layer.
getMetric:
  Return a metric operations (buffer, length, area, convex hull).
getNN:
  Nearest Neighbors (not implemented yet).
getRelation:
  Look for spatial relations as contains, crosses, touches.
getSetMetric:
  Calculate a set operation (union, difference, intersection, xor).
openTheme:
  Open an existent theme.
plot:
  Plots the data.
showTables:
  Show all information tables in the layer.

### Author(s)

Marcos Aurelio Carrero, Pedro Ribeiro de Andrade Neto

### See Also

See `aRTlayer-METHOD` for a method of this class or `CLASSNAME-class` for links to other classes. Package spproj for conversion of projections.

[Package aRT version 0.4-0 Index]