Poor accuracy of the boundaries

Home › Forums › General › Announcements & General Questions › Poor accuracy of the boundaries

Tagged: 

Viewing 3 posts - 1 through 3 (of 3 total)
  • Author
    Posts
  • June 30, 2011 at 3:12 pm #3447

    Beanz
    Participant

    I’ve downloaded 10m_admin_0_countries containig country borders.

    Then I converted it to KML by shp2kml (http://www.zonums.com/shp2kml.html) and compared

    with satellite.

    http://imageshack.us/photo/my-images/15/offsetyn.jpg/

    As you can see at the image – there are little offset between google and Natural Earth data. What is the reason? maybe datum?

    June 30, 2011 at 5:46 pm #4186

    Nathaniel
    Keymaster

    Natural Earth is 99% accurate for the low-precession it aspires to. This is meant to be a general world dataset. When you zoom into country boundaries in Google Earth you’re going 100x the intended display resolution of this dataset.

    July 1, 2011 at 11:28 am #4187

    Beanz
    Participant

    At the screenshot the blue filled polygon is NaturalEarth data. The Yellow line is Google Earth, the Light blue line is Wikimapia.

    I want to say that all (almost all) polygons from NaturalEarth are shifted to the west at about 3km, and to the south at about 1km.

    I think that this inaccuracy comes not from zoom, but from datum. It must be a WGS84.

  • Author
    Posts
Viewing 3 posts - 1 through 3 (of 3 total)

You must be logged in to reply to this topic.