Computer modeling of line-track with in-situ sample data in the application of remote sensing technology

Reliable in-situ sample data is essential to run the remotely sensed (RS) model and to check the RS result. Existing in-situ data collection methods are ruler measurement by manual work or tracking the parcel by high-accuracy Global Position System (GPS). The former is time-consuming and lacks spatial information, while the latter is costly and the GPS signal is not stable. On account of this, the paper develops a new approach named line-track to get reliable in-situ sample data. The main idea can be described as follows: first, we locate the sample by high-accuracy GPS; then we lay sample lines at certain intervals both horizontally and vertically and obtain the percentage of certain objective on each sample line. In the end we calculate the percentage of objective in the sample. This idea is similar to the line transect in ecology, which is used to estimate wildlife densities. By computer modeling, this paper sets up an accuracy assessing model of line-track, and analyzes the variation of the accuracy of line-track under different conditions, such as distribution of objective, the actual percentage of objective in a sample, and the distance of two sample lines. The modeling of line-track demonstrates that the total accuracy of covering of certain objective at the middle percentage, that is from 15% to 85%, is about 97% when the distance of two sample lines is less than twelve meters, and it would be about 95% at high or low percentage when the distance is less than twenty meters. Such results suggest that line-track is reliable to obtain accurate in-situ data due to less dependence on time and cost. The development of the line-track will strongly support the collection of in-situ sample in the application of RS technology.