arc.open: Open dataset, table, or layer

In R-ArcGIS/r-bridge: Bindings for ArcGIS

Open dataset, table, or layer

Description

Open ArcGIS datasets, tables, rasters and layers. Returns a new arc.dataset-class object which contains details on both the spatial information and attribute information (data frame) contained within the dataset.

Usage

  arc.open(path)

Arguments

path	file path (character) or layer name (character)

Value

An arc.dataset-class object

Supported Formats

• Feature Class: A collection of geographic features with the same geometry type (i.e. point, line, polygon) and the same spatial reference, combined with an attribute table. Feature classes can be stored in a variety of formats, including: files (e.g. Shapefiles), Geodatabases, components of feature datasets, and as coverages. All of these types can be accessed using the full path of the relevant feature class (see note below on how to specify path names).

• Layer: A layer references a feature layer, but also includes additional information necessary to symbolize and label a dataset appropriately. arc.open supports active layers in the current ArcGIS session, which can be addressed simply by referencing the layer name as it is displayed within the application. Instead of referencing file layers on disk (i.e. .lyr and .lyrx files), the direct reference to the actual dataset should be used.

• Table: Tables are effectively the same as data frames, containing a collection of records (or observations) organized in rows, with columns storing different variables (or fields). Feature classes similarly contain a table, but include the additional information about geometries lacking in a standalone table. When a standalone table is queries for its spatial information, e.g. arc.shape(table), it will return NULL. Table data types include formats such as text files, Excel spreadsheets, dBASE tables, and INFO tables.

• rasters: Rasters represent continuous geographic data in cells, or pixels, of equal size (square or rectangular). Spatial data represented on this rasters are also known as grided data. In contrast to spatial data structures represented in feature classes, rasters contain information on spatially continuous data.

References

• What is the difference between a shapefile and a layer file?

• ArcGIS Help: What is a layer?

• ArcGIS Help: What are tables and attribute information?

Note

Paths must be properly quoted for the Windows platform. There are two styles of paths that work within R on Windows:

• Doubled backslashes, such as: C:\\Workspace\\archive.gdb\\feature_class.

• Forward-slashes such as: C:/Workspace/archive.gdb/feature_class.

Network paths can be accessed with a leading \\\\host\share or //host/share path. To access tables and data within a Feature Dataset, reference the full path to the dataset, which follows the structure: <directory>/<Geodatabase Name>/<feature dataset name>/<dataset name>. So for a table called table1 located in a feature dataset fdataset within a Geodatabase called data.gdb, the full path might be: C:/Workspace/data.gdb/fdataset/table1

See Also

arc.select, arc.raster, arc.write

Examples

## open feature
filename <- system.file("extdata", "ca_ozone_pts.shp",
                          package="arcgisbinding")
d <- arc.open(filename)
cat('all fields:', names(d@fields), fill = TRUE) # print all fields

## open raster

filename <- system.file("pictures", "logo.jpg", package="rgdal")
d <- arc.open(filename)
dim(d) # show raster dimension

R-ArcGIS/r-bridge documentation built on May 3, 2024, 9:47 a.m.