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# ArcInfo

ESRI ArcInfo Coverage Files are also known as simply as Coverages and less commonly as ADF files.

## File listing

Coverages are made up of a set of files within a folder. The folder itself is the coverage name. The files roughly represent different layers, usually representing different types of topology or feature types.

    > ls /data/coverage/brazil
    aat.adf  arc.adf  arx.adf  bnd.adf  lab.adf  prj.adf  tic.adf  tol.adf

A folder with the name INFO is also part of the coverage. It sits at the same hierarchical level as the coverage folder itself. Therefore, to copy a coverage (using regular file system tools) the coverage folder and the INFO folder must both be copied. The INFO folder holds some catalogue information about the coverage.

    > ls /data/coverage/info
    arc0000.dat  arc0001.dat  arc0002.dat  arc.dir
    arc0000.nit  arc0001.nit  arc0002.nit

## Data Access / Connection Method

- CONNECTIONTYPE OGR must be used. The ability to use coverages is not built into MapServer.

- The path to the coverage folder name is required.

- The layer name (feature type) is specified in the DATA parameter

### OGRINFO Examples

The directory is the data source. Layers are found within the directory. Using ogrinfo on a coverage directory:

    > ogrinfo /data/coverage/brazil -summary
    INFO: Open of `brazil'
    using driver `AVCBin' successful.
    1: ARC (Line String)
    2: CNT (Point)
    3: LAB (Point)
    4: PAL (Polygon)

Using ogrinfo to examine the structure of a layer:

    > ogrinfo /data/coverage/brazil PAL -summary
    Had to open data source read-only.
    INFO: Open of `brazil'
    using driver `AVCBin' successful.

    Layer name: PAL
    Geometry: Polygon
    Feature Count: 1
    Extent: (1272793.274958, 795381.617050) - (1287078.382785, 807302.747284)
    Layer SRS WKT:
    (unknown)
    ArcIds: IntegerList (0.0)
    AREA: Real (18.5)
    PERIMETER: Real (18.5)
    F_OPER#: Integer (5.0)
    F_OPER-ID: Integer (5.0)
    OPER: String (2.0)
    FCODE: String (10.0)

Map File Example:

    LAYER
      NAME Brazil_bounds
      TYPE POLYGON
      STATUS DEFAULT
      CONNECTIONTYPE OGR
      CONNECTION "/data/coverage/brazil"
      DATA "PAL"
      CLASS
        NAME "Brazil Admin Areas"
        STYLE
          OUTLINECOLOR 153 102 0
          SIZE 2
        END
      END
    END