Content-type: text/html Man page of SMFILTER

SMFILTER

Section: SMfilter User's Manual (1)
Updated: 2011-09-09
Index Return to Main Contents

NAME

smfilter - Seamark filter reads an OSM/XML file and preprocesses nodes with the tag 'seamark:type=*'.

SYNOPSIS

smfilter [OPTIONS] [< inputfile] [> outputfile]

DESCRIPTION

smfilter is a tool which is part of the OpenSeamap rendering process. It is a preprocessor run before the actual task of rendering. smfilter reads an OSM file from stdin, processes sectored lights, and outputs the result in OSM format to stdout again. The output contains all the input data plus additional nodes, ways and tags which are generated for the sectors of lights. This simplifies the rendering process and reduces data within the OSM database.

smfilter is written in C and is based on libhpxml which is included in the package. Libhpxml is a high preformance XML stream parsing library. Thus, smfilter is suitable to parse huge OSM files, for example the planet file ;).

Sectors of lights are defined by several tags. This is defined in the OpenSeamap lights data model. Start and end of sectors are defined by seamark:light:#:sector_start=* and seamark:light:#:sector_end=*. The values are given in degrees from 0° to 360°. Please note that these are bearings from observer to the light which means that they are rotated by 180 degrees. This definition is common to mariners. smfilter reads and parses this sector data and adds two radial ways and the sector arc in form of OSM nodes and ways to the OSM file. This can then be simply rendered by the renderer through applying style sheets to these ways.

The radial ways and arcs are tagged with information required by the renderer to complete the process. The tags for the radial ways are seamark:light_radial=<n> and seamark:light:object=<type> being n the number of the sector and type the type of the light as defined by the seamark:type=<type> of the seamark node.

The arc ways are tagged with seamark:light:sector_nr=<n>, seamark:light:object=<type>, and seamark:arc_style=<style>; style is one of "solid", "suppress", "dashed", "taper_1", "taper_2", "taper_3", "taper_4", "taper_5", "taper_6", or "taper_7". The default of smfilter is to choose "solid". The behavior of smfilter can be influenced by the map editor with the tag seamark:light:#:radius=* (see below).

Note that these ways and their tags form private, virtual data and are not used within the OSM database. They only have a transient existence, between the output of smfilter and the input of Osmarender.

RADIUS TAG

seamark:light:#:radius=* (see OSM-Wiki:Rendering Sector Arcs) is an optional tag for influencing the behavior of smfilter. It defines the radius of the sector and other information to change rendering on the map. Please note that this does not have any relevance for navigation.

The value of seamark:light:#:radius=* is defined as follows:

seamark:light:#:radius = <arcdef>[;<arcdef>][;...]
<arcdef> ::= [<radius>][:<secdef>]
<secdef> ::= <segment>[:<style>] | <style>[:<segment>]
<radius> ::= Radius in nautical miles.
<segment> ::= Angle of the arc segment in degrees relative to sector_start.
<style> ::= 'solid' | 'dashed' | 'suppress' | 'taper_up' | 'taper_down'

<segment> may also be given as a negative number. In that case it is measured backwards starting at sector_end. This is only valid if it is used in the last <arcdef>. If just a single <arcdef> is defined, a virtual solid arc segment is inserted before (see sector 3 of example below).

<radius> and <segment> must be any sole fractional number without units (they would simply be ignored). Negative values of <radius> would result in a default value being used.

If the sum of angles of all segments is not equal to the range of the sector, smfilter will squeeze or enlarge them to fit the actual range of the sector (see sector 2 of example below). There is always is a mapping error and will probably result in a rendering which was not desired by the mapper. In case of using a negative value for <segment> in the last <arcdef>, smfilter will stretch the previous <arcdef> appropriately, if it does not have a <segment> defined (see sectors 1 and 5 of example below).

EXAMPLE OF LIGHT DEFINITION

<?xml version='1.0' encoding='UTF-8'?> <osm version='0.6' generator='Bernhard R. Fischer'>
   <node id='1' version='1' visible='true' timestamp='2008-07-25T11:12:13Z' lat='38.3' lon='25.1'>
      <tag k='seamark:name' v='smfilter test object' />
      <tag k='seamark:type' v='light_minor' />
      <tag k='seamark:light:character' v='Fl' />
      <tag k='seamark:light:period' v='8' />
      <tag k='seamark:light:orientation' v='230' />
      <tag k='seamark:light:category' v='directional' />
      <tag k='seamark:light:radius' v='1.2' />
      <tag k='seamark:light:1:sector_start' v='40'/>
      <tag k='seamark:light:1:sector_end' v='70'/>
      <tag k='seamark:light:1:colour' v='white'/>
      <tag k='seamark:light:1:radius' v='1:10;:dashed;:solid:-10'/>
      <tag k='seamark:light:2:sector_start' v='120'/>
      <tag k='seamark:light:2:sector_end' v='190'/>
      <tag k='seamark:light:2:colour' v='red'/>
      <tag k='seamark:light:2:radius' v='.5:20;:10:suppress;:10:dashed;0.7:10:solid'/>
      <tag k='seamark:light:3:sector_start' v='300'/>
      <tag k='seamark:light:3:sector_end' v='20'/>
      <tag k='seamark:light:3:colour' v='green'/>
      <tag k='seamark:light:3:radius' v='.3:-25:suppress'/>
      <tag k='seamark:light:4:sector_start' v='25'/>
      <tag k='seamark:light:4:sector_end' v='35'/>
      <tag k='seamark:light:4:colour' v='red'/>
      <tag k='seamark:light:4:radius' v='1.5'/>
      <tag k='seamark:light:5:sector_start' v='250'/>
      <tag k='seamark:light:5:sector_end' v='300'/>
      <tag k='seamark:light:5:colour' v='red'/>
      <tag k='seamark:light:5:radius' v='1:15:taper_up;:solid;:-15:taper_down'/>
   </node> </osm>

OPTIONS

-a dist: This sets the maximum distance of arc nodes. Basically, the distance is scaled with the radius; the smaller the radius the smaller the distance and vice versa. With large radii the distance of nodes is limited to dist. The value is given in nautical miles.
-b deg: Leading and directional lights are rendered with a bearing line and a small arc at its end. deg sets the angle of this arc to one side which means it is drawn def degrees clockwise and def degress counterclockwise from the bearing line.
-d div: This defines the arc divisor which is used to determine the distance of the arc nodes. Thus, the node distance equals the radius divided by div. (see also option -a).
-h: Display short usage message and shows options.
-H: In the past, the OpenSeamap lights data model used a special tag to give a hint to the renderer in the format seamark:light:#=<col>:<start>:<end>:<r>. This optional enables smfilter to parse this tag also. Please note that this tag is deprecated, hence, smfilter ignores it by default.
-l logfile: smfilter may encouter some errors during the parsing process. Such errors are output to the file named logfile.
-r radius: I light may not have any radius specified since the tag is optional. In such cases smfilter picks radius as default value.

NOTES

This man page is still not finished...

AUTHOR

Concepts, software, and man page written by Bernhard R. Fischer, 2048R/5C5FFD47 <bf@abenteuerland.at>.

COPYRIGHT

Smfilter is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 3 of the License.

Smfilter is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with smfilter. If not, see <http://www.gnu.org/licenses/>.

Index

NAME

SYNOPSIS

DESCRIPTION

RADIUS TAG
EXAMPLE OF LIGHT DEFINITION
OPTIONS

This document was created by man2html, using the manual pages.
Time: 18:36:16 GMT, September 09, 2011