The Nasca lines or geoglyphs in southern Peru are known as one of archaeology's greatest mysteries. Since the 1980s, however, new approaches have helped to better understand their function and meaning. The recent photogrammetric recording of 1 500 geoglyphs in the vicinity ofPalpa enabled for the first time a GIS-based analysis. Geoglyph visibility is one of their most discussed traits. While m...

We present an approach to determine the credibility of content provided within a visual VGI source such as Flickr. We propose analysing the variability of selected user and photo metadata of geotagged Flickr photos with the location correctness of these images, which is our reference quality measure. These observed user and photo metadata can help to infer the credibility of contributors.

Premise The genetic structure between plant populations is facilitated by the spatial population arrangement and limited dispersal of seed pollen. Saxifraga acerifolia, a local endemic species in Japan, habitat specialist that confined to waterfalls riparian environments. Its sister species, fortunei, generalist widely distributed along riverbanks. Here, we examined sympatric two test whether d...

A new species of Dorstenia L. (Moraceae), Dorstenialuamensis M.E.Leal, is described from the Luama Wildlife Reserve, west of Lake Tanganyika and north of the town of Kalemie in the eastern part of the Democratic Republic of Congo (DRC). This species is endemic to the region and differs from any of the other species by its fernlike lithophytic habit and lack of latex. A description and illustrat...

The recent availability of detailed geographic data permits terrain applications to process large areas at high resolution. However the required massive data processing presents significant challenges, demanding algorithms optimized for both data movement and computation. One such application is viewshed computation, that is, to determine all the points visible from a given point p. In this pap...

The calculation of viewsheds is a routine operation in GIS and is used in a wide range of applications. Many of these involve the siting of features, such as radio masts, which are part of a network and yet the selection of sites is normally done separately for each feature. The selection of a series of locations which collectively maximise the visual coverage of an area is a combinatorial prob...