Tornado damage assessment near Gera, Germany
Around 20 ha of an urban forest area covered with approx. 80% conifers and 20% deciduous trees was affected by this event.
In consultation with the EUFODOS User ThüringenForst, GAF AG used the opportunity to demonstrate the usability of the Forest Downstream Service “Non-Rush-Damage Assessment”, where damaged forest areas with a minimum area of 0,3 ha have to be assessed.
The Service uses EO and HR Forest CORE datasets as the basis for reference mapping. High resolution satellite data (RapidEye) has been acquired after the Tornado in order to facilitate the damage assessment.
The overall workflow to derive potentially damaged areas included a segmentation based change classification algorithm between Core EO data and EO data after the Tornado.
Additionally, the Tree Cover Density product (part of the High Resolution Forest Core Layers) has been used to further minimize potential classification errors.
The animation below includes the High Resolution Core EO Data set from IRS acquired in 2009 (Image A), the Tree Cover Density map derived from IRS (Image B), the RapidEye Image acquired after the Tornado (Image C) and as a result the classified damaged forest areas as an overlay (Image D) to the RapidEye data.
© RapidEye (2012); Antrix Corporation Limited 2009 - distribution by Euromap GmbH, Germany, all rights reserved. Provided under EC/ESA GSC-DA.