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California county lines in your GPS? you county listers can now have them

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  • Elias Elias
    Howdy CalBirders? I made an announcement a few days back regarding this topic on the County Birders listserv. I thought that the wider audience of CalBirds
    Message 1 of 1 , Dec 9, 2009
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      Howdy CalBirders?

      I made an announcement a few days back regarding this topic on the County
      Birders listserv. I thought that the wider audience of CalBirds may be
      interested as well.

      Joseph Morlan has been kind enough to host the file. The direct link is:
      http://fog.ccsf.edu/~jmorlan/CountyLines.htm

      California County Lines/Listing Boundaries file
      If you are a county lister and often ask "What county is that bird in?"
      then this file is for you.

      In this day of high-tech devices available to ordinary citizens, there is no
      reason why listing boundaries can't be precisely codified in map form so
      that when you are in the field you can know when you cross over the line.
      This is my first stab towards that end and I consider Phase 1 complete. In
      this file you will find county boundaries for all of California's counties
      and offshore islands out to 3nm. The data come from two sources. The first
      source was more precise and the second source drew the county lines to the
      3nm buffer. I really don't know the provenance of the first coverage but I
      got it from Pablo Herrera and it is more precise because it more closely
      follows the old thalweg of the rivers and creeks which defined the counties
      in the 1800's. It also follows the ridgelines more closely in those
      instances where ridges define the boundaries. The second source was
      downloaded from Tiger Line which is curated by the Census Bureau. I opted to
      use this for the coastal counties because it continued the county line
      offshore to the limit of what is county jurisdiction. Actually what I have
      done is retain both versions, so that is why you will find two shapes for
      all the coastal counties. Each island group also has their own shape. Note
      that the shapes in the Census Bureau dataset contain some errors. When you
      find errors, I would like these brought to my attention if you think they
      deviate more than 30 meters from reality. I am currently working on taking
      the county lines further off shore. My goal for Phase 2 is to take them all
      the way to the 200nm limit.

      This file is in GDB format. It is a format which you can use to load spatial
      data into Garmin's MapSource software and then into their GPSs. If a GDB
      file doesn't interface with your favored GPS interface program. I'd suggest
      downloading GPSBabel <http://www.gpsbabel.org/> which is a file type
      converter. It surely will have what you need for turning it into a format
      which you can use. Once the file is loaded to your GPS, these images (see
      webpage) are what you can expect.


      Best wishes

      Elias Elias
      Arcata CA
      707-633-8833
      559-433-7254 walkie-talkie


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