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       llsearch  -  Search a GNIS file for place names within a given block of


       llsearch   [-L]    |    [latitude_low    longitude_low    latitude_high


       The  U.S.  Geological  Survey  supports  sites  on  the  Internet  with
       Geographic Names Information System (GNIS) files.  These files  contain
       lists  of place names, complete with their latitude/longitude and other
       information.  There are separate files for each of the U.S. states, and
       each  file  contains  many, many, many place names.  If you want to use
       this data with drawmap, it is useful to reduce the  data  to  only  the
       items  that  you need.  Llsearch lets you filter a GNIS file and winnow
       out only those place names  that  fall  within  the  latitude/longitude
       boundaries  that you specify.  (You may want to specify boundaries that
       are a tiny bit  larger  than  what  you  are  interested  in,  so  that
       numerical  quantization  doesn’t eliminate locales that fall exactly on
       your boundaries.)

       Latitudes and longitudes are  positive  for  north  latitude  and  east
       longitude,   and  negative  for  south  latitude  and  west  longitude.
       Llsearch expects you to enter them in decimal degrees.  (The  latitudes
       and  longitudes in the GNIS file are in degrees-minutes-seconds format,
       followed by ’N’, ’S’, ’E’, or ’W’.  However, there  are  two  available
       file   formats,   and   one   of   the   formats   also   contains  the
       latitudes/longitudes in decimal degrees.)  Typical usage is as follows:

       gunzip    -c   california.gz   |   llsearch   33   -118   34   -117   >

       If  you  enter  the  "-L"  option,  the program will print some license
       information and exit.

       Once you have reduced the data to some  subset  of  interest,  you  can
       search  for  particular  items  via the grep or perl commands, or other
       search commands, or you can simply edit the results with your  favorite
       text  editor.   Search commands are useful in reducing the sheer volume
       of data to a more manageable size (by  extracting,  say,  all  mountain
       summits  or  all  streams),  but  you  will  probably ultimately end up
       looking through the remaining data manually.   The  individual  records
       contain  codes,  such  as  "ppl" for populated places, and "summit" for
       mountain tops, that can help you pick and choose.

       There is considerable redundancy in place names, and human intelligence
       is  useful  in  sorting  things  out.   While I was writing drawmap and
       llsearch, I frequently gazed out my office window, where I  could  spot
       at least two, and possibly three Baldy Mountains.  There are also quite
       a few Beaver Creeks, Bear Canyons, Saddle Buttes, and Springfields  out
       there.   By taking a close look at the information associated with each
       place name, you can find the particular locations that interest you.



                                 Jul 24, 2001