Coordinates in KML slightly different from those shown in Google Earth

Question

When I open the KML file in Excel, The coordinates of the same placemark are different from those shown in Google Earth. For example, coordinate point of a placemark shown in Google Earth itself is 24.484138°, 54.400700° but in KML (when open in Excel) is 24.48586802, 54.40060011. Please help me how to correct it. Thanks.

Answer 1

The underlying KML may have many decimal places in the coordinates. This is what you'll see in Excel or if you view the KML file in a text editor.

Here is a KML placemark location with 10 decimal places:

<Placemark>
    <name>Google office</name>
    <description>This is the location of Google</description>
    <Point>
        <coordinates>-122.0123456789,37.0123456789</coordinates>
    </Point>
</Placemark>

Google Earth stores all the digits, but it only displays up to 6 coordinates. This is not a loss in precision or accuracy -- only a display issue.

But realize that 6 decimal places precision in coordinates is at a 10 cm resolution. Each .000001 difference in coordinate decimal degree is approximately 10 cm in length. The imagery of Google Earth is typically at the 1 meter resolution, and some places have the highest resolution of 1 inch per pixel. One meter resolution can be represented using 5 decimal places so more than 6 decimal places is not necessary.

Answer 2

It could be that Google Earth is storing the coordinates in a different coordinate system than it is displaying them. When I used to work in GIS,it was common to use multiple data sets which use different coordinate systems together. ArcGIS would do some of the basic transformation automatically to place all of the data into a common coordinate system. I'm not sure if Google Earth does something similar. You may get a better answer from gis.stackexchange.com.