select_stations

Section: WIN SYSTEM (1W)
Updated: 2004.1.29
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NAME

select_stations - Selects observation point of arbitrary zone from file in channel table format  

SYNOPSIS

select_stations ch_file polygon_file

 

DESCRIPTION

Select_stations selects a line (channel) of observation point positioned inside a polygonal zone specified by  polygon_file from a file of channel table format  ch_file, and writes in the standard output. However, the channels of which latitude and longitude are omitted in  ch_file are bypassed. Refer to win(1) for format of channel table file.
Format of  polygon_file is as follows: Coordinates (latitude and longitude in degree are delimited by blank or tab) of vertices of a polygon are arranged in order of clock-wise with one point per line. It is necessary to close the polygon by making the last vertex coincide with the first one. It is allowed that vertices of a polygon are concave.

Select_stations checks each side of a polygon showing the zone in order of clock-wise, and when a point is found to the right (viewed from start point to end point) of the side closest to the point, it determines the point exists inside the polygon.

When select_stations is initiated without argument, brief usage is displayed.  

OPTIONS

None.
 

SOURCE

select_stations.c
 

SEE ALSO

win(1W)  

BUG

Serious bug found in the early program (Nov. 9, 1999 Version) was corrected in Jan. 28, 2004 Version.


 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
SOURCE
SEE ALSO
BUG

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Time: 00:23:51 GMT, September 20, 2017