| 1. | This method has four parts : data acquisition , image processing , pixel number extraction and coverage calculation . , based on the precision assessment , the error is very small , and it has advantages such as objectivity , consistency and high precision , compared with visual estimation methods 精度评价表明,该方法测定的绿色植被盖度误差很小,与目视估测方法比较,它具有客观、一致和精度高的优点。 |