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.