[mapserver-users] S57 Marine Charts on mapserver?

[Lars Schylberg]

I can just agree what Daniel said.  It can be done and I even know about 
three groups that have done it.  I am in one of those groups and have 
worked on nautical S52 presentation done with Mapserver configurations 
for a little more than one year.  My experience is that it can be done 
as good or even better than the big commercial GIS vendors.  Our goal 
has not been to produce a nautical map for navigation.  It has been done 
for planning purposes and as a base map.  I am still working on this 
project and I will see next year what parts we could release as open.  
At least I think that we could contribute to the Mapserver documentation 
around these issues.

Back to the S52 symbology standard.  The standard describes point 
symbols, line symbology and area patterns in a file that has the 
extension:   “.dai”.  It uses the pen plotter style of description, ie 
pen up, pen down, move to, to describe around 150 – 200 different 
symbols, lines types and patterns. The syntax in the .dai file is the 
old graphic standard HPGL.   It is of course very precise but You have 
to interpret it and turn it into something useful for the mapfile syntax.

There are different ways to do this.  The opencpn project and some 
others have used the code in opencpn and made bitmaps of the symbols 
that easily could be used in mapserver.

Others have converted the .dai files to svg.  This is the way IHO seems 
to be going also with the upcoming new S102 standardization. They will 
replace .dai files with svg files and other xml constructions to 
describe lines and patterns. There is currently a limitation in 
mapserver to go this way, that I have mentioned in mapserver-dev 
questions earlier this year.

http://osgeo-org.1560.x6.nabble.com/svg-symbols-setting-color-outline-width-outline-color-td5231065.html

This is of course if You want to implement all different color modes.

The approach we have used, is a mix of true type symbols and native 
mapserver symbology.  Actually I prefer the native mapserver symbology.  
This is more or less the same as HPGL line to xy, line to xy and -99 for 
pen up.  So I have made some of the point and line symbols into native 
mapserver symbology symbols.  These have been edited by hand based on 
the stroke descriptions in the dai or svg files.  Then You could set 
color and width in the mapfile.

I did write a little about  s57 data handling in a mapserver-users entry 
back in September

https://lists.osgeo.org/pipermail/mapserver-users/2015-September/078251.html

One group that has shown how to convert S57 to postgis and display it 
with mapserver for one single chart is this Russian group:

https://github.com/nextgis/navi2pg

You can find a lot inspiration how the mapfiles are written.  They have 
used bitmap symbols.

Even if I don’t speak or read Russian, I think You could grasp most of 
it anyway.  Google translate can also help for specific words.

Personally I would prefer to have an end state with a spatialite 
database (or geopackage with symbology included) for the S57 databases 
but right now I am using shapefiles.

Good luck

Lars Schylberg