This paper examines the effects of database generalization on the area which is determined to be visible in GIs analysis. Many different methods of generalization are possible, but here, for any cell at the target resolution, elevations are determined from: the arithmetic mean, the maximum, the minimum, and the maximum difference from the mean of the cells within the kernel, and all possible co...

Flow characteristics are a prominent factor determining body shapes in aquatic organisms, and correlations between body shape and ambient flow regimes have been established for many fish species. In this study, we investigated the potential for a brief period of extreme flow to exert selection on the body shape of juvenile climbing Hawaiian gobiid fishes. Because of an amphidromous life history...

The viewshed of a topographic dataset is the region around a given observation point that is visible from that location. Most GIS packages allow its computation. It has many uses, such as in urban environment planning, or in analysing archaeological site data. The viewshed is used here as a data enhancement tool to aid in the interpretation of geophysical potential field data. The fraction of t...

, where E(x=La) is the erosion rate at the upstream end of the flow acceleration zone above a waterfall, Fr is the Froude number at this setting, and n ranges between 0.5–1.7. This amplification expression suggests that erosion at the lip could be as much as 2–5 times higher relative to erosion at a normal setting with identical hydraulic geometry. Utilizing this erosion amplification expressio...

For rivers or streams with waterfalls, water withdrawal for multiple uses can lead to potential conflicts of interest. The question arises what extent impairs the appearance and acoustics waterfalls. A data set was analyzed 15 waterfalls different morphological types in Switzerland, Austria, Norway. It comprises discharge measurements as well photo imaging sound level measurements. variations w...

Nowadays, there is a huge volume of data about terrains available and generally, these data do not fit in the internal memory. So, many GIS applications require efficient algorithms to manipulate the data externally. One of these applications is the viewshed computation that consists in obtain the visible points from a given point p. In this paper, we present an efficient algorithm to compute t...

This study was conducted to investigate the seasonal variation of water qualities for drinking and conservation aquatic organisms from river, lake waterfalls in Chattogram Hill Tracts Bangladesh during pre-monsoon, monsoon post-monsoon seasons period March 2021 February 2022. Water samples were collected four sampling locations analysed research laboratory Department Environmental Science Resou...