to identify critical sediment sources in large catchments, using easily available terrain information at a regionalscale, a methodology was developed to obtain a qualitative assessment necessary for environmental management.fargas et al method was employed in the research. the study was carried out in one of the sub-basins of hableh roodbasin called dehnamak in the arid and semiarid climate of ...

With rapid new technological development during the past 50 years, aerial photos have been increasingly and commonly used not only in geographic information systems but also in various spatially related applications. Many municipalities and government agencies have constructed aerial photo databases all over the world. Keeping these databases up to date is the most important part of making them...

Historic aerial photos are typically very popular, sought-after collections in library archives. Their ability to be used in GIS is limited, however, by the laborious and painstaking georeferencing process. A method is presented for automating the georeferencing of historic aerial photography. In this method, the Harris Corner Detector is used to detect corner points in already-georeferenced an...

gully erosion is one of the most complicated and destructive forms of water erosion. in order to prevent this erosion, the important factors advancing gully head must be recognized. nowadays, several models have been proposed in measuring gully head advancement and identifying the severity of erosion. these models must be calibrated for each country to see whether they are applicable or not. so...

LiDAR has become important data sources in urban modelling. Traditional methods of LiDAR data processing for building detection require high spatial resolution data and sophisticated methods. The aerial photos, on the other hand, provide continuous spectral information of buildings. But the segmentation of the aerial photos cannot distinguish between the road surfaces and the building roof. Thi...

Building models are conventionally reconstructed by measuring their vertices point-by-point in a digital photogrammetric workstation (DPW), which is time and labor consuming process. Although aerial photos implicitly provide 3D information of buildings, LiDAR systems directly provide high density and accurate point cloud coordinates. However, LiDAR data cannot accurately represent the building ...

Aerial photos are the best support to detect changes in the landscape over the time, particularly when associated with GIS based analyses. Since all metrics calculated on a landscape (from area coverage by vegetation classes to patches shape and size) are sensible to geometric distortions, the geometric correction of aerial photos is due to allow a realistic multi-temporal study. In this paper ...

The Ministry of agriculture of the Czech Republic has defined a pilot project to summarize possible information that can be automatically evaluated from black and white aerial photos. This information should serve as input data into the large forest database or as signal data for forest state management organizations. These data were derived in traditional and modern ways. The traditional one u...

abstract recognition of effective factors on landslide occurrence and so high and low hazard region is one of the most important and necessary works for mitigation of landslide damages. in this study, from all of the effective factors on landslide occurrence, land use changes and road construction, into a parts of tadjan watershed with area about 708.08 square kilometers in south of sari, was s...

Image maps generated using satellite images and aerial photos are extremely useful. The map can provide detailed topographic, land-use and land-cover information on earth. With the growing number of satellite and aerial photo data, a technique which can generate/update maps automatically from satellite images and aerial photos is necessary. This paper presents a technique developed at PCI Geoma...