Vegetation Height Model NFI

Countrywide **vegetation height models (VHM)** were generated for Switzerland based on **stereo aerial images**, acquired by the Federal Office of Topography swisstopo. From the ADS-80/100 sensor data, first a digital surface model (DSM) with a spatial resolution of 1 × 1 m is processed. This DSM is then normalized using the digital terrain model (DTM) swissALTI3D (swisstopo). Buildings and other artificial objects are masked out from the nomalized DSM (nDSM) using information from the topogrphic landscape model - TLM (swisstopo) to obtain the actual vegetation height model (VHM). These VHM's are produced in the framework of the Swiss National forest Inventory (NFI). Each year about 1/6 of Switzerland's surface is updated using the leaf-on aerial images acquired by swisstopo (may - october). Further information on the creation of the VHM NFI can be found in the paper Ginzler and Hobi (2015, https://doi.org/10.3390/rs70404343).瑞士联邦地形局（swisstopo）通过采集的立体航空影像，为瑞士全境生成了植被高度模型（Vegetation Height Models, VHM）。研究基于ADS-80/100传感器的影像数据，首先处理得到空间分辨率为1×1米的数字表面模型（Digital Surface Model, DSM）。随后，借助瑞士联邦地形局发布的数字地形模型（Digital Terrain Model, DTM）swissALTI3D对该数字表面模型进行归一化处理。研究人员进一步利用瑞士联邦地形局提供的地形景观模型（Topographic Landscape Model, TLM）的相关信息，从归一化数字表面模型（normalized DSM, nDSM）中掩膜剔除建筑物及其他人工地物，从而得到最终的真实植被高度模型（VHM）。上述植被高度模型是在瑞士国家森林清查（Swiss National Forest Inventory, NFI）的框架下生成的。每年，瑞士联邦地形局都会利用5月至10月获取的有叶期航空影像，更新该国约1/6国土面积的植被高度模型数据。关于该植被高度模型生成方法的更多详细信息，可参阅Ginzler与Hobi于2015年发表的论文（https://doi.org/10.3390/rs70404343）。