Changeset 547 in ntrip for trunk/ntripclient


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Timestamp:
Oct 23, 2007, 12:54:01 PM (12 years ago)
Author:
stuerze
Message:

source table filter description added

File:
1 edited

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  • trunk/ntripclient/README

    r497 r547  
    3333of RTCM via Internet Protocol' (Ntrip). This is an application-level
    3434protocol streaming Global Navigation Satellite System (GNSS) data over
    35 the Internet. Ntrip is a generic, stateless protocol based on the
    36 Hypertext Transfer Protocol HTTP/1.1. The HTTP objects are enhanced
    37 to GNSS data streams.
     35the Internet. Ntrip Version 1.0 is a generic, stateless protocol based
     36on the Hypertext Transfer Protocol HTTP/1.1. The HTTP objects are
     37enhanced to GNSS data streams.
     38
     39The primary motivation for Ntrip Version 2.0 is to develop a fully
     40HTTP-compatible Internet protocol standard that would work with proxy
     41servers and to add an optional data transport via UDP. Hence, one
     42Ntrip Version 2.0 transport approach is still based on HTTP1.1 on top
     43of TCP. The second Ntrip Version 2.0 transport approach is based on
     44both, the Internet Standard Protocol RTSP (Real Time Streaming Protocol)
     45for stream control on top of TCP and the Internet Standard Protocol RTP
     46(Real Time Transport Protocol) for data transport on top of
     47connectionless UDP.
    3848
    3949Ntrip is designed for disseminating differential correction data
     
    6272
    6373ntripclient -s server -u user ...
    64  -d --data      the requested data set
     74 -d --data      the requested data set or criteria for sourcetable filtering
    6575 -s --server    the server name or address
    6676 -p --password  the login password
     
    8393The argument '-h' will cause a HELP on the screen.
    8494Without any argument ntripclient will provide the a table of
    85 available resources (source table).
     95available resources (sourcetable).
     96
     97Sourcetable filtering
     98----------------------
     99A missing argument '-d' leads to the output of the complete broadcaster
     100sourcetable. This may comprise hundreds of lines in case of large
     101networks. To limit the output, the sourcetable contents can be filtered
     102through entering the argument '-d' followed by a sequence of query strings,
     103one for each sourcetable data field. Only those sourcetable lines are
     104returned from the broadcaster whoes data fields match the corresponding
     105query strings. A sequence of query strings has to be initiated by a '?'
     106and a semicolon is acting as query string delimiter in analogy to the
     107sourcetable data field delimiter.
     108
     109Note that for fully understanding the sourcetable filtering option
     110you have to make yourself familiar with the details of the sourcetable
     111contents. In general, search criterias can be applied on each sourcetable
     112data field.
     113
     114The following query string operators are available for integer and
     115floating-point numbers in the sourcetable lines:
     116
     117- Equation operators: <, >, >=, <=, =, != (not equal)
     118- Approximation operator: ~n (find value with minimal distance to n)
     119
     120The following query string operators are available for alphanumeric
     121strings in the sourcetable lines:
     122
     123- Wildcard operator: '*' means any number of characters
     124- Alternation operator: expression|expression
     125- Grouping operator: (expression)
     126- Any character matching for strings (case insensitivity)
     127
     128The following operators are available for both text as well as integer
     129and floating-point numbers in the sourcetable lines:
     130
     131- Logical operators: ! (NOT), & (AND), | (OR)
     132- Grouping operator: [!] (Expression)
     133
     134Examples:
     135
     136- Searching in a sourcetable for streams in Germany would require
     137  entering the '-d' argument followed by
     138  the query string:
     139  ?STR;;;;;;DEU
     140
     141- Searching in a sourcetable for free streams fom the EUREF network and
     142  coming from the Frankfurt area would require entering the '-d' argument
     143  followed by the query string:
     144  ?STR;;;;;;;EUREF;;=>50&<=51;=>8.1&<8.6;;;;;N
    86145
    87146Compilation/Installation
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