What is resolution?

When Earth scientists talk about different types of remotely sensed imagery, they often refer to a sensor's "resolution." Resolution refers to the spatial, spectral, radiometric, and temporal characteristics of the sensor and therefore of the data it collects.

Spatial resolution lets you know how large an object on the Earth must be to show up in the sensor's imagery. Put another way, a sensor's spatial resolution is the size of the smallest object that can be seen in the sensor's imagery.

Spectral resolution refers to the ability of the sensor to detect electromagnetic radiation at different wavelengths across the electromagnetic spectrum. In general terms, spectral resolution is the ability to detect different colors (i.e., wavelengths) of light.

Radiometric resolution is the ability of the sensor to quantify different amounts of energy at specific wavelengths. A sensor's ability to detect low to high amounts of detected energy is called the dynamic range of the sensor.

Temporal resolution refers to the frequency with which a sensor can collect imagery over the same spot on the Earth. Many satellite sensors have a repeat time in the range of 2 to 3 weeks.