From the size of a mountain to the size of a 50 cents coin
Since the launch of the first Earth observation satellite in 1959, the world has witnessed incredible developments in terms of platform and sensors to observe the Earth. It is now possible to see virtually any part of our planet and distinguish objects the size of a mountain up to the size of a coin.
The spatial resolution of an image can vary from a few kilometres up to a few millimetres depending on the platform and sensor used to capture an area. From continent size monitoring of the earth surface to ultra-precise engineering survey applications, possibilities to exploit these Earth observation mapping technologies are almost infinite.
The pictures below show how Adelaide looks like through the eyes of some of the most popular Earth observation sensors still operational.
GOES satellites: 4km Spatial resolution
These geosynchronous satellites orbit at about 36,000km above the Earth and provide continuous weather observation and monitoring.
NOAA Satellites: 1.1km Spatial resolution
These polar-orbiting satellites are used for long-term forecasting and provide land and oceanic information among other services.
MODIS: 250m Spatial resolution
MODIS is a key instrument aboard Terra and Aqua satellites and provide information to understand global dynamics and processes occurring on the land, in the oceans and in the lower atmosphere.
Landsat-5: 25m Spatial resolution
As part of the Landsat program to provide resources for land applications, this old Earth observation satellite has significantly exceeded its designed life expectancy by over 22 years.
SPOT-4: 10m Spatial resolution
This Earth observation satellite part of the SPOT family (built by the French) provides capabilities for geological reconnaissance vegetation surveys and survey of snow cover. It even got a mention in the cyberpunk classic “Snow Crash“.
SPOT-5: 2.5m Spatial resolution
The big brother of SPOT-4 can provide multispectral data as well as stereopair images to map relief
Ikonos: 1m Spatial resolution
Ikonos was the first satellite to collect publicly available high resolution imagery at 1m resolution.
Worldview-2: 0.5m Spatial resolution
This satellite currently provides images with the highest resolution possible available to the public. It is between 1m to 0.5m resolution that aerial and satellite imagery overlap in term of capability and depending on the application, one technology will be more suitable than the other.
UltraCam-D digital aerial: 20cm Spatial resolution
Microsoft UltraCam has a well-earned reputation for technical excellence and produce high quality large format cameras systems.
UltraCam-X digital aerial: 25mm Spatial resolution
High quality aerial imaging systems make the acquisition of ultra-high resolution information possible and are currently used for engineering survey application.
The progress of sensor technology over time gives a distinct “Powers of Ten” feel to the navel gazing performed by humanity. We are finding a higher and higher perch to look closer and closer at ourselves.