1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
/*
* =========================================================================
* llsearch - A program that extracts a subset of the data in a GNIS file.
* Copyright (c) 1997 Fred M. Erickson
*
* This program 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; either version 2, or (at your option)
* any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
* =========================================================================
*
*
* This is a filter to search a GNIS file for any entries within
* the specified latitude/longitude box.
*
* Each GNIS file is for a separate state, but some of the larger
* states span many degrees of latitude and longitude.
* It is convenient to be able to pull out just the data you need
* for a given map.
*
* The program reads from stdin and writes to stdout.
*/
#include <sys/types.h>
#include <stdlib.h>
#include <stdio.h>
ssize_t buf_read(int, void *, size_t);
ssize_t buf_write(int, const void *, size_t);
ssize_t get_a_line(int, void *, size_t);
double lat_conv(unsigned char *);
double lon_conv(unsigned char *);
main(int argc, char *argv[])
{
unsigned char buf[16384];
double latitude_low;
double latitude_high;
double longitude_low;
double longitude_high;
double latitude;
double longitude;
ssize_t ret_val;
if (argc != 5) {
fprintf(stderr, "Usage: %s latitude_low longitude_low latitude_high longitude_high\n", argv[0]);
fprintf(stderr, " (The latitude/longitude values are in decimal degrees.)\n", argv[0]);
exit(0);
}
latitude_low = strtod(argv[1], (char **)0); /* We assume that these are in decimal degrees */
longitude_low = strtod(argv[2], (char **)0); /* We assume that these are in decimal degrees */
latitude_high = strtod(argv[3], (char **)0); /* We assume that these are in decimal degrees */
longitude_high = strtod(argv[4], (char **)0); /* We assume that these are in decimal degrees */
if ((latitude_high < -90.0) || (latitude_high > 90.0) ||
(latitude_low < -90.0) || (latitude_low > 90.0) ||
(longitude_high < -180.0) || (longitude_high > 180.0) ||
(longitude_low < -180.0) || (longitude_low > 180.0)) {
fprintf(stderr, "Error: Parameters appear incorrect\n");
exit(0);
}
if ((latitude_high < latitude_low) || (longitude_high < longitude_low)) {
fprintf(stderr, "Error: Parameters appear incorrect\n");
exit(0);
}
while ((ret_val = get_a_line(0, buf, 16384)) > 0) {
/* These are in degree/min/sec format */
latitude = lat_conv(&buf[149]);
longitude = lon_conv(&buf[156]);
if ((latitude >= latitude_low) &&
(latitude <= latitude_high) &&
(longitude >= longitude_low) &&
(longitude <= longitude_high)) {
write(1, buf, ret_val);
}
}
}
|
