Document Type : Research Paper
Authors
1 Senior Research Expert of Watershed Management, Research Institude of Forest and Rangelands, AREEO
2 Research Associate, McGill University, Canada
3 Senior Expert in Remote Sensing of Forest, Range watershed Management Organization of Iran
Abstract
Aerial images are systematically utilized in most scientific contexts to undertake exploration and measurement operations. Image matching techniques for the acquisition of the ground truth in order to create thematic maps have always been facing difficulties and challenges. In this research, the LPS module from the ERDAS Imagine9.2 software was used to develop geomorphological landforms maps of the Harzand Chai watershed. The methodology used was based on analytical photogrammetric techniques (Two Dimension Affaine) using aerial photographs (1:40000). Harzand Chai watershed’sgeomorphological landforms maps were prepared using both traditional and photogrammetric methods. The map prepared by photogrammetric method was compared after field visit and matching the type of landforms with the acquisition of the ground truth, with the map prepared by conventional method that is used for creating thematic maps in our country. To perform a statistical test for evaluating the prepared map of the geomorphological landforms, 100 points were determined by the ERDAS Imagine9.2 software on the provided maps, and then about 62 points of them were taken using the GPS (Ground Positioning System) and the characteristics of each was written down. Statistical test was performed by Stratified random sampling method using ERDAS Imaginge9.2 software to examine two prepared maps.The resultant map was then matched with the real features and compared with the map developed by traditional methods used in the thematic mapping process in Iran. According to the findings of the statistical test, the percentage of the total accuracy for the geomorphological landforms map developed by the analytical photogrammetric technique was %95. The Kappa Index value for this map was estimated to be 0.9. These values for the geomorphological landforms map created by the conventional method were %84 and 0.76 respectively. Therefore, the geomorphological landforms map created by the analytical photogrammetric method was selected as the best representation of the geomorphological features of the Harzand Chai watershed.
Keywords
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