[gdal-dev] How to read catalog file

[Frank Warmerdam]

On 12-11-19 09:29 PM, Nikhil Sai Parupalli wrote:
> Hi All,
>
> I have developed an application on VB.Net with GDAL as interface to read S57
> dataset.
> Everything is fine , here I have to read some information form S57 catalog file .
> I have tried using stream reader in VB.net, but unable to fetch the values
> correctly.
> Can any one help me out in reading S57 catalog file using GDAL and vb.net .

Nikhil,

The catalog files are relatively simple ISO8211 format files.  My
8211view utility (mainline in gdal/frmts/iso8211) shows the following.
Unfortunately, the low level ISO8211 data access is not currently
provided through the public GDAL API (as an OGR dataset for instance).
So I'm not sure how you would be able to access it from VB.net
easily.

Possiblilities include:
  1) you provide your own callout to C++ and from there call the 8211
     library in GDAL (see http://home.gdal.org/projects/iso8211/index.html)
  2) Run the 8211view.exe exectable and parse the result - messy!
  3) someone writes a small OGR driver for generic ISO8211 files. I
     already once did something similar for FME but the feature model
     there is much more flexible.

warmerda at gdal65[374]% 8211view CATALOG.030
Record 1 (87 bytes)
     Field 0001: ISO 8211 Record Identifier
     Field CATD: Catalog Directory field
         RCNM = `CD'
         RCID = 1
         FILE = `CATALOG.030'
         LFIL = `'
         VOLM = `V01X01'
         IMPL = `ASC'
         SLAT = 0.000000
         WLON = 0.000000
         NLAT = 0.000000
         ELON = 0.000000
         CRCS = `'
         COMT = `Exchange Set Catalog file...'
Record 2 (110 bytes)
     Field 0001: ISO 8211 Record Identifier
     Field CATD: Catalog Directory field
         RCNM = `CD'
         RCID = 2
         FILE = `No410810.000'
         LFIL = `'
         VOLM = `V01X01'
         IMPL = `BIN'
         SLAT = 59.000005
         WLON = 4.999996
         NLAT = 59.500003
         ELON = 5.499997
         CRCS = `555C3AD4'
         COMT = `'
Record 3 (58 bytes)
     Field 0001: ISO 8211 Record Identifier
     Field CATD: Catalog Directory field
         RCNM = `CD'
         RCID = 3
         FILE = `README.TXT'
         LFIL = `'
         VOLM = `V01X01'
         IMPL = `ASC'
         SLAT = 0.000000
         WLON = 0.000000
         NLAT = 0.000000
         ELON = 0.000000
         CRCS = `'
         COMT = `'

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