Name
ESRI ArcInfo Coverage Files
Synopsis
ESRI ArcInfo coverage files are also known 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 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 ...
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