File listing

ESRI ArcInfo Coverage Files

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ESRI ArcInfo coverage files are also known simply as coverages and, less commonly, as ADF files.

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 filesystem tools), the coverage folder and the INFO folder must both be copied. The INFO folder holds some catalog 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 isn't built into MapServer.

• The path to the coverage folder name is required.

• The layer number is used to specify what type of features to draw (as per the layer number from ogrinfo, but minus one).

ogrinfo examples

• The directory is the data source.

• Layers are found within the directory.

Here's an example that uses ogrinfo on a coverage directory:

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

Here's an example that uses ogrinfo to examine the structure of a layer:

     > ogrinfo -summary /data/coverage/brazil PAL     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, 3"       CLASS         NAME "Brazil Admin Areas"         OUTLINECOLOR 153 102 0         SIZE 2       END     END