With Google Earth providing high-resolution imagery to the everyday user, it is expected from Satellite imagery to be pf very high resolution. However, that is not the case in Remote Sensing. The use of high-resolution imagery is limited to very specific applications. High- resolution images are not easily available as they are expensive, need high processing power and time, and require relatively larger storage.

What is the Spatial Resolution of Satellite Imagery Data?

Spatial resolution refers to the size of one pixel on the ground or the maximum detail one can see from an image. A pixel is that smallest ‘dot’ that makes up an optical satellite image and basically determines how detailed a picture is. Sentinel-2 data, for example, has a 10m resolution in the optical bands, meaning each pixel stands for a 10m x 10m area on the ground. It’s considered a medium-resolution image, which can cover an entire city area alone, but the level of detail isn’t fine enough to distinguish individual objects like houses or cars.

Satellite Images & other Earth Observation datasets are divided into the following categories based on Resolution. They are as follows:

Several resampling methods can be used to upscale or downscale the resolution of satellite images. Resampling methods include Nearest Neighbour, Bilinear Interpolation, Cubic Convolution, etc. When we have high-resolution imagery, we can downscale it to any lower resolution. On the other hand, when upscaling low-resolution imagery to higher resolutions, it can be done only to an extent, after which it results in errors and noise. 

Advanced methods such as Super-Resolution Imaging can also be used to improve the details of the imagery. Super Resolution For details on Optical Super Resolution, see the use case here:

Other types of resolution include Spectral, Radiometric, and Temporal. Spectral Resolution is the ability of a satellite sensor to measure specific wavelengths of the electromagnetic spectrum (How many bands? How narrow/ wide are the bands?). Radiometric Resolution is how finely a satellite or sensor divides up the radiance it receives in each band ( the number of bits for each band). Temporal Resolution is the time between the acquisition of two subsequent images over the same area (revisit time).