I can take a stab at this.
Are we talking about user submitted images of key spots to Google Maps which includes both flat and spherical images, icons? Will this also include all the images shot by 360′ street view, and user submitted photos (both flat and spherical)? I’ll assume, yes.
Calculating type of assets and file sizes –
1. Assets used –
a. Flat Photos – A 12 Megapixel photo is anywhere from 5-20 MB based on compression. We can go with 5MB assuming there are some compression algorithms.
b. Spherical Photos ( 360 ) – Google Maps now has street view 360 maps on many roads in N. America. But these are limited to roadways, key landmarks & national parks. Possibly around 15MB each
c. Icons, Text – average around 5KB
Calculating Google Maps coverage –
Google Maps has maps covering most of the world both urban & rural. So I would start by calculating the habitable area in the world.
We know that radius of earth is 6500 km’s. Surface area of earth would then be 4 x Pi x r (squared) ~ 500 Million sq. km’s. Earth is about 25% land, so land area is 125 Million sq. km’s. Assuming about 40% of this is habitable, we end up with 50 Million sq. km’s.
Now let’s assume Google has covered at least 70% of this habitable area = 35 M sq. km’s.
Calculating volume of assets –
1. Per 10 sq. km we can assume there are an average of at least 50 points of interest (gas stations, restaurants, parks, homes, etc.) which demand image assets.
2. Total number of national parks and landmarks in the world, let’s assume about 100,000 that have some sort of spherical media uploaded.
3. Assuming MAU’s on Google Maps is around 1 Billions users. Let’s assume about 10% upload at least 20 images to Maps. This gives us 2 Billion images uploaded
4. Per 10 sq. km we can assume there are an average of about 10 roads and 20 homes which demand icons or copy assets
a. Assuming 70% of roads have spherical media
With math above we arrive at these numbers on approximate number of assets stored in the cloud –
1. Points of Interest Images = 50 * 35 M sq. km/10 sq. km = 175 M images
2. 100,000 Landmarks with 100 spherical images each = 10 M spherical images
3. 2 Billion images uploaded by users
4. Roads & Homes
a. 70% * 35/10 * 10 = 25M spherical images
b. 35/10 * 20 = 7M images
5. Icons & Copy – assuming this as a total of all the above (points of interest + uploaded images + landmarks roads) = 2.875 B
Flat images – 2.875 B * 5 MB = 14,375 TB
Spherical images – 35 M * 15 MB = 525 TB
Icons & Copy – 2.875B * 0.005 MB = 14.3 TB
Total storage = ~15K TB or 15 PB