Google Earth News & Map Data Sources

I’ve been using Google Earth version 5.2.1.1329 (beta) for some time and I find the measurement tab of the path properties dialog very useful. Another very handy feature appears when you right click on a path, the Show Elevation Profile option creates a nice interactive elevation chart.


I stumbled upon a good resource for free online historical maps the other day, Maps ETC from the University of South Florida. In addition to the nice maps they also provide some good basic tutorial videos for Google Earth.


While I was updating some of my Blackstone Valley places files I discovered the Map of all coordinates from Google link on a Wikipedia National Register of Historic Places list article. Clicking the link plots all the sites in Google Maps, but if you click the show link over to the right you get more mapping options. One of the options, Export all coordinates as KML, lets you load the place locations directly into Google Earth.

I decided to load up all the Wikipedia data for Massachusetts and Rhode Island, wow, there are a lot of sites. So I made a version limiting the places to those that fall within the boundary of the Blackstone River Valley National Heritage Corridor.

Most of the sites are not positioned precisely so, I’m tweaking the positions as I work on exploring the BRVNHC. During a recent editing session I found that the National Register of Historic Places provides Google Earth files with some locations updated with more accurate TeleAtlas data. Loading these files along with my my custom file helps in locating the historic sites.

One feature I’m editing into the files I have not found a way to do through GE itself. This is setting the placemark style variations for normal versus highlighted. I’ve set the style so that normally there is no label but when you point to the placemark the label appears and the icon grows. You get this effect by setting up the style block like this:

<StyleMap id="msn_star">
    <Pair>
        <key>normal</key>
        <styleUrl>#sn_star</styleUrl>
    </Pair>
    <Pair>
        <key>highlight</key>
        <styleUrl>#sh_star</styleUrl>
    </Pair>
</StyleMap>
<Style id="sn_star">
    <IconStyle>
        <Icon>
            <href>http://maps.google.com/mapfiles/kml/shapes/star.png</href>
        </Icon>
    </IconStyle>
    <LabelStyle>
        <scale>0</scale>
    </LabelStyle>
</Style>
<Style id="sh_star">
    <IconStyle>
        <scale>1.2</scale>
        <Icon>
            <href>http://maps.google.com/mapfiles/kml/shapes/star.png</href>
        </Icon>
    </IconStyle>
</Style>

With no scale parameter specified for an IconStyle the default value is 1, and with no LabelStyle parameter the label scale defaults to 1.