We have recently been looking at our map created from the Google Maps API’s Maximum Zoom data:
Google Maps API Maximum Zoom – Part 1: Data collection
Google Maps API Maximum Zoom – Part 2: Overview
Google Maps API Maximum Zoom – Part 3: Starting on a more detailed look
Google Maps API Maximum Zoom – Part 4: Continuing the detailed look
Today we are continuing with the detailed look, this time at the Americas.
As we have seen with other areas, South America has two sets of background imagery. Low resolution Landsat imagery is used in the northern half of the continent and the southern countries of Central America. There is also a patch of Landsat imagery in the eastern part of Brazil
The rest of the continent uses Cnes/Spot Image as the background image.
High resolution satellite imagery largely matches the population density and is sparsest over the Amazon Rain Forest. We had expected to see a lack of imagery over the Andes due to snow cover, but in fact it seems the Andes have relatively good coverage. The approximate line of the Amazon River can also be seen to have better coverage than surrounding areas.
Spots of aerial imagery can be seen in a number of Brazilian cities and Cordoba, Argentina. In all the areas we checked, the imagery showed no attribution, suggesting it belongs to Google, probably gathered during its 3D imagery collection. Note that 3D imagery is not included in this data and South America does have quite a lot of 3D imagery.
Landsat imagery is used as the ‘background’ for northern Canada. The Great Lakes also show up as this resolution, but they have sea floor data (supplied by NOAA), not satellite imagery. Lake of the Woods, a lake in Northern Minnesota, has low resolution imagery attributed to Terrametrics, as is Lake Victoria in Africa.
Mexico and much of Canada use Cnes/Spot Image as the background imagery. Interestingly it seems to have a northernmost limit of about 60.3°N
High resolution satellite imagery coverage is poor over Canada, especially towards the North. Mexico has reasonably good satellite imagery coverage.
Canada and Mexico do have some small patches of aerial imagery. The US is notable for being entirely covered with aerial imagery. Even the lighter shades in the US are low resolution aerial imagery. Although a lot of the imagery was actually gathered by Google, the complete coverage can be attributed to government agencies, which gather aerial imagery and Google has obtained it from them.
The US has a number of extra dark red patches indicating extra high resolution aerial imagery.
Note that the US, Canada and Mexico all have significant 3D imagery that is not included in this data.