Depth-contours are an essential part of any hydrographic chart—a map of a waterbody intended for safe ship navigation. Traditionally these were manually drawn by skilled hydrographers from a limited set of surveyed depth measurements. Nowadays this process of map making is shifted towards the digital domain, not in the last place because of the sheer size of the point clouds that result from mo...

This paper compares the performance of topographic analysis and binary analysis for recognition of digits in hydrographic maps. The performance of each method was measured by the correct classification rate of the final symbol recognition step when processing a complete hydrographic map of size 0.45× 0.6m with about 35,000 digits. The experimental results indicated that binary analysis had a be...

This paper compares the performance of topographic analysis and binary analysis for recognition of digits in hydrographic maps. Each of the methods processed the input image by extracting binary print components, recognizing long lines, splitting touching digits, and, finally, recognizing individual symbol candidates. The topographic analysis extracted the information by computing topographic l...

A wide variety of climate and terrain conditions exist in the United States and optimal cartographic generalization techniques for one area of the country may not be suitable for another, particularly when working with surface hydrographic data. This paper presents generalization and data modelling to produce reduced scale versions of hydrographic data for a multi-resolution national data set, ...

In this paper, the El-Hames empirical method was used to determine the peak runoff flow in Iranshahr catchment. The El-Hames method is based on morphological parameters and SCS Curve Number of the studied area. The implementing was processed by collecting the required data including soil type and vegetation cover, land use maps, digital elevation model and satellite images from the associated i...

Vegetation coverage can be inappropriately used, especially in the absence of proper planning, and can result in a reduction of the occupied area. Demographic and economic alterations are factors that contribute to the degradation of vegetation coverage in landscape units. In addition, because vegetation is essential for protection of recharge areas in aquifers, the fragmentation of habitats in...

Variability of hydrographic conditions and primary and secondary productivity between cold and warm climatic regimes in the Bering Sea has been the subject of much study in recent years, while interannual variability within a single regime and across multiple trophic levels has been less well-documented. Measurements from an instrumented mooring on the southeastern shelf of the Bering Sea were ...