[Qgis-developer] S57 map files

Hamish hamish_b at yahoo.com
Mon Jan 19 19:11:58 EST 2009

Florian wrote:
> So here are my questions:
> - has anyone ever worked with S57 and OGR and/or Qgis?

Hi there,
I usually don't follow the qgis-dev list but I happened to notice your
post by chance.

FYI I have spent some time working with ENC/S-57 data, the S-52 rules for
rendering S-57 data, and access via ogr so it can be used in software
like qgis, grass, and gpsdrive. It is an ongoing/reoccurring requests for
S-57 display with GpsDrive (which already has similar live map generation
from OpenStreetMap PostGIS vector DBs).

some links:
  http://grass.osgeo.org/wiki/S-57_data  (see QGIS plugin section)


AFAIU OGR has access to the S-57 data well in-hand. But this gives you
access to a flood of cryptic data layers and for any sort of sane
rendering you will want to follow the S-52 rules. Rather than try and
do that manually (a nightmare), S52CS.c from libS52 is already there
waiting to be used. My idea was that as a start if a CLI wrapper tool
could be written around libS52 to export a table of active
"layer_name|RGB_values" for a given map scale & color scheme* those
layers could be automatically loaded/enabled with the given colors fed
into the QGIS layer Properties.

* (eg "bright day" or "night mode")

due to dynamic nature of S-52 display this would IMO best be done as a
qgis plugin with a few drop down menus to help you tune it to your needs.
(the rendering rules change with depth-of-ship [ground contours you can
collide with are more vibrantly colored], color scheme/brightness choice,
map scale [shows all layers at harbor-scales, hides some otherwise],
metadata layers interesting to map-makers but not end-users, etc)

AFAICT libS52 is near completion; I am in occasional contact with the
main devel, he's still interested.

As you can do serious physical damage if you trust this data too much,
and we propose to supply access to it free for anyone of any ability,
there is a bit more responsibility than normal to get things "right" and
support things like drop-in updates to keep it current.

off-topic but perhaps of interest:
- FWIW there is also some ongoing discussion over at GpsDrive wrt
rendering live AIS data via direct locally running parsing server or via
Gpsd (http://gpsd.berlios.de). [think modern air traffic control radar
screen but with data from large ships' transponders overlaid on the map]

- besides the new GDAL GRIB format driver, checkout the GPL'd "ZyGrib"
for real-time weather forecast downloads & mapping. (www.zygrib.org)


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