What does radiometric accuracy in raster data measure?

Radiometric accuracy in raster data refers to how accurately the cell values represent the actual conditions of the earth's surface at the time the data was gathered. This means that the focus is on the correctness of the pixel values, which can represent different characteristics such as reflectance values from satellite imagery or temperature readings.

The correct choice emphasizes the importance of ensuring that the pixel values correspond to real-world conditions, confirming that the data accurately reflects what was being measured during the specific time of data acquisition. If the cell values are not accurate, interpretations and analyses based on that raster data could lead to erroneous conclusions.

In contrast, distinguishing between various features pertains to the concept of spectral resolution rather than radiometric accuracy. This relates to how well different materials or land cover types can be identified from one another based on their unique spectral signatures. Overall accuracy in positioning refers to the geometric correctness of where the raster data is aligned, and the method of data collection would influence all types of accuracy but does not specifically define radiometric accuracy.