Abstract This article surveys measurements of celestial (chiefly solar) altitudes documented from twelfth- and thirteenth-century Latin Europe. It consists four main parts providing (i) an overview the instruments available for altitude described in contemporary sources, viz. astrolabes, quadrants, shadow sticks, torquetum; (ii) a survey role played by determination geographic latitude, which t...

Speed-up techniques that exploit given node coordinates have proven useful for shortest-path computations in transportation networks and geographic information systems. To facilitate the use of such techniques when coordinates are missing from some, or even all, of the nodes in a network we generate artificial coordinates using methods from graph drawing. Experiments on a large set of German tr...

Population counts and longitude and latitude coordinates were estimated for the 50 largest cities in the United States by computational linguistic techniques and by human participants. The mathematical technique Latent Semantic Analysis applied to newspaper texts produced similarity ratings between the 50 cities that allowed for a multidimensional scaling (MDS) of these cities. MDS coordinates ...

In recent years there has been a growing interest in the application of geographic information systems (GIS) for the development of spatial decision support systems (SDSS). The current paper presents the development of a GISbased SDSS for precision management of tree crops. The SDSS is being developed within the framework of the '3D-Mosaic' project which aims at optimizing water consumption in ...

BACKGROUND AND AIMS Allowing for dispersal limitation, a species' geographic distribution should reflect its environmental requirements. Comparisons among closely related species should reveal adaptive differentiation in species characteristics that are consistent with their differences in geographic distribution. This expectation was tested by comparing characteristics of seedlings of spruce s...

Polyploidy and symbiotic Epichloë fungal endophytes are common and heritable characteristics that can facilitate environmental range expansion in grasses. Here we examined geographic patterns of polyploidy and the frequency of fungal endophyte colonized plants in 29 Festuca rubra L. populations from eight geographic sites across latitudes from Spain to northernmost Finland and Greenland. Ploidy...

Anopheles (Cellia) maculatus Theobald is a major malaria vector in southern Thailand and peninsular Malaysia, and previous population genetic studies suggested that mountain ranges act as barriers to gene flow. In this study, we examine the genetic variance among 12 collections of natural populations in southern Thailand by analyzing 7 microsatellite loci. Based on analysis of molecular varianc...