[gdal-dev] OGR about s_57

Frank Warmerdam warmerdam at pobox.com
Tue Sep 1 13:46:56 EDT 2009

Randy wrote:
> Hi, everyone,
>    I=A1=AFm now interesting in displaying ENCs.
>    I know the OGR can support the s57 format files and it can get some=20
> data like point=A1=A2line=A1=A2polygon. But it cannot support the style=
s as Mr=20
> Frank Warmerdam told me. Now, I have such questions:
> 1.       Where can I know what OGR does support and does not support=20
> about s57 ? Does it get the symbols(no, right?)?


OGR does not read the actual graphical symbols.  For instance,
we might have a feature from the WRECKS layer like below with
various valuable attributes, but actual wreck symbol.

  RCID (Integer) =3D 2164
  PRIM (Integer) =3D 1
  GRUP (Integer) =3D 2
  OBJL (Integer) =3D 159
  RVER (Integer) =3D 1
  AGEN (Integer) =3D 540
  FIDN (Integer) =3D 2135161787
  FIDS (Integer) =3D 688
  LNAM (String) =3D 021C7F43FBBB02B0
  NAME_RCNM (IntegerList) =3D (1:110)
  NAME_RCID (IntegerList) =3D (1:517)
  ORNT (IntegerList) =3D (1:255)
  USAG (IntegerList) =3D (1:255)
  MASK (IntegerList) =3D (1:255)
  CATWRK (Integer) =3D 1
  QUASOU (String) =3D 2
  WATLEV (Integer) =3D 3
  POINT (61.1031909 -32.4450159)

> 2.       If I have got the color and symbols, How could I know which=20
> kind of color the line(or polygon or something else which I get with th=
> help of OGR) should match with?

You would normally read the S52 specification and use it to
determine appropriate coloring, styling and symbolization
from the attributes of a feature.   I haven't actually reviewed
the S52 specification, but I imagine it has rules for how
to draw wrecks that might indicate different symbols depending
on the CATWRK (Category of Wreck) and WATLEV (Water level
effect) attributes of the feature.

> 3.       Has anyone done such things, can you help me something?

I know lots of people have made various levels of effort in
following the S52 specification based on OGR as a feature
reader.  Perhaps some of them will speak up and volunteer
additional information.

> 4.       I know the file =A1=B0IHO ECDIS Presentation Library=A1=B1 can=
 help me=20
> but I don=A1=AFt know how to get it, can you?

Normally the IHO web site should have instructions on ordering.

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox=
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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