Calculation Method of water body density index and vegetation coverage index

The meteorological Evaluation Standard for ecological quality (Trial) issued by the China Meteorological Administration stipulates:

 

The water body density index refers to the proportion of the water area in the evaluated area to the area in the evaluated area. The water area includes the area of rivers, lakes, and reservoirs; vegetation Coverage index refers to the proportion of forest land, grassland and farmland in the evaluated area. The specific calculation method is as follows:
Water Body density index = water area/area.

The water area uses the average water area during the evaluation period, including the water area of rivers, lakes, and reservoirs.
Vegetation Coverage Index = (0 · 5 × forest area × growth period + 0 · 3 × grassland area × growth period + 0 · 2 × farmland area × growth period)/area.

The growth period is the percentage of growth time (d) to 365 D of the year. If it is evaluated quarterly, the growth period is the percentage of growth time (d) to the quarter time (d.

 

There is also the vegetation index:

Normalized Difference Vegetation Index: the calculation of the reflectivity of the two bands (NIR-R)/(NIR + r.
1. Application of the platform to detect vegetation growth status, vegetation coverage, and elimination of some radiation errors;
2.-1 <= SVD <= 1. A negative value indicates that the ground is covered with clouds, water, and snow, and High Reflection on visible light. 0 indicates that there are rocks or bare soil, nir and R are approximately the same. positive values indicate vegetation coverage and increase with the increase of coverage;
3. the limitations of the Gini difference are that the contrast of the reflectivity of the NIR and R is enhanced by nonlinear stretching. For the same image, when finding The RVI and the SVD respectively, it is found that the increase rate of The RVI value is higher than the increase rate of the SVD value, that is, the latter has a lower sensitivity to the high vegetation area;
4. The background Effects of the Plant Canopy can be reflected by the difference between the vegetation coverage and soil, wet ground, learning, dead leaves, and roughness.

 

 

These indicators are also available in ecological analysis and ecological planning.