Improving the quality of borders in Google Earth and Maps

Tuesday, July 20, 2010 at 5:33 PM

At Google, we are constantly making improvements to all of our products, from Search to Gmail, Blogger to Chrome. When it comes to products like Google Earth and Google Maps, we work hard to improve our cartography and depict geopolitical features as accurately as possible. Last year, we discussed the ways we strive towards that accuracy, and today we are happy to announce some significant improvements to our borders for over 60 countries and regions (the updates are live in Maps and are coming to Google Earth shortly). To provide some background on this update, we thought we would take the opportunity to talk a bit more about our approach to mapping geopolitical features like borders.

Making Google's mapping tools as accurate as possible is a complex process, especially when a map's accuracy has both quantitative and qualitative aspects. We receive spatial data of all kinds - imagery, boundaries, place names, etc. - from a variety of sources worldwide, and we review them carefully before integrating them into the best representation of a given location in Google Earth and Maps.

In the case of geopolitical features on our maps, the depiction of borders is something upon which local authorities, governments and internationally recognized bodies often disagree. Our goal is to provide the most legible and accurate maps we can given the information available in these oft-changing areas of geopolitical disagreement. Like most maps, ours include symbology that makes borders and other geopolitical features clearer to users. For example, we employ various boundary styles in Google Earth and Maps to clarify the current status of boundary lines, viewable here in the Help Center.

Similar to satellite imagery, boundary data is available in varying levels of resolution; the higher the resolution, the better the boundaries will follow specific geographic features, such as rivers. While we always strive to display the on-the-ground reality of a boundary's position, in practice some boundary lines are not as accurate as we would like them to be due to the available resolution of our boundary data.

With these improvements, many borders will now more closely follow natural boundaries such as mountains and rivers. The pictures below show a portion of the border between Tajikistan and Kyrgyzstan, which follows the Pamir Mountain Range, near the Zervashan River. As you'll see, the new data follows the mountain ridgeline quite closely, even when zoomed in, which is a great improvement in positional accuracy.

before:

after:



In some areas we have improved our qualitative accuracy by changing the symbology of the boundary lines to reflect the updated status of a treaty or agreement based on political changes, new agreements or negotiations. This portion of the border between Ethiopia and Somalia changed from solid (yellow in Google Earth) - meaning "international" - to dashed (red in Google Earth) - meaning "disputed" - to reflect the ground-based reality that the two countries maintain an ongoing dispute in the Ogaden region.

before:
after:




In other cases our previous boundaries lacked key details and the new data provides more information. For example, we now show a disputed island near the borders of Brazil, Uruguay and Argentina:

before:



after:



There are many other examples of both quantitative and qualitative changes we've made to improve our maps and we invite you to explore them. We will certainly continue to update and improve upon the borders and other geopolitical features in Google Earth and Maps, keeping in mind that the dynamic nature of such areas presents a significant cartographic challenge. Mapping is a field where there is never total agreement, but we try to do our best and will continue to develop new ways to meet these challenges. As always, we are happy to hear from our users with any questions and concerns about our approach to these complex issues.