Métodos de orlado para la evaluación de la exactitud altimétrica en modelos digitales de elevaciones del terreno

Resumo

Traditionally, the altimetric accuracy assessment of digital elevation models (DEM) has been carried out using standards (e.g., National Standard for Spatial Data Accuracy) based on sampling of points in the reference model (S1) and in the model to be assessed (S2). These standards have two drawbacks: 1) the points are scarce compared to the total surface of a DEM and therefore they leave a large ground area not assessed, 2) the surface assessment is carried out comparing points, when it seems more suitable to assess by surfaces comparison. Both drawbacks can be overcome by surface buffer methods. This work presents for the first time in the altimetric assessment field the methods of single buffer (MOS) and double buffer (MOD) on surfaces. The study has been carried out on synthetic data. It has been proved that both methods allow the detection of outliers and biases when assessed S2. In addition, observed distribution functions can be elaborated, which eliminate the need to consider normality hypotheses about the discrepancies and allow applying some quality control techniques through tolerances.