Remotely sensed images are increasingly being used for collection of spatial information. A wide development in sensor systems has occurred during the last decades, resulting in improved spatial, temporal, and spectral resolution. The collection of data by remote sensing is generally more efficient and cheaper than by direct observation and measurement on the ground, although still of a varying quality. Data collected by sensors may be
affected by atmospheric factors between sensors and the values reflected on the earth's surface, local impurities on the earth's surface, technical deficiencies of sensors and other factors. In addition, only the reflection of the sensor's signal or of the sunlight on the earth's surface is being measured, and no direct measurements are made. Consequently, the quality of maps produced by remote sensing needs to be assessed
