[Qgis-user] S-57 Support

[Brent Wood]

--- Chris H <chris123 at magma.ca> wrote:

> Greets:
> 
> Im still stuck on trying to understand the issues with S-57 data files. From 
> discussions on IRC it seems that GQIS is hard coded to read only one layer at
> a time, not multiple layers which makes this file format not supported at 
> this time. 
> 
> First off, is this assumption correct? Secondly if it is, is there a 
> workaround as I would like to use QGIS for a project Im planing. Finally if 
> S-57 is not supported at this time, would it be possible to be file an 
> enhancement request?

Hi Chris,

I believe QGIS uses GDAL/OGR to access S-57 datasets. These data include a
range of attributes not supported by common GIS formats, such as shapefiles,
and the OGR support is (unfortunately) read only. Any issues with QGIS and S-57
access are probably better addressed in GDAL/OGR forums.

One workaround would perhaps be to implement a PostGIS database essentially
replicating your S-57 data, generated automatically or manually from the S-57
files, and use this to provide the data to be plotted by QGIS. 

I assume the issues with an S-57 writer is that many of the fields in this
format are not easily derived from many other GIS formats, so a straightforward
conversion is often not possible, thus a generic writer has not been
implemented, making it difficult to move the PostGIS data back to S-57.

Information about the support for S-57 provided by GDAL/OGR is at:
http://www.gdal.org/ogr/drv_s57.html
http://home.gdal.org/projects/s57/index.html

I'm not a great fan of managing data in shapefiles, but they are a useful
format for transferring data between applications. An application like the new
CARIS S-57 composer, which can import shapefiles to generate S-57 files, might
be useful, but is commercial software. Knowing Caris & GIS generally, it
probably ain't cheap. 

An approach building & managing your data in PostGIS, then exporting to
shapefile to build S-57 charts with the Caris software might be viable, and
still much cheaper that a totally commercial solution. This would allow QGIS &
most other FOSS GIS tools to interact with the data, for viweing, editing &
managing it.

http://www.caris.com/news/story.cfm?id=41


HTH,

  Brent Wood



> 
> I rather new to this so apologies in advance if the assumptions are
> incorrect. 
> Basically I just looking for some input on how to handle these file formats 
> with QGIS. 
> 
> Many thanks
> 
> -- 
> /ch
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