Search results for "Variogram"
showing 3 items of 13 documents
On the orientational analysis of planar fibre systems from digital images
2002
The orientational characteristics of fibres in digital images are studied. The fibres are modelled by a planar Boolean model whose typical grain is a thick (coloured) fibre. The aim is to make stereological inference on the rose of directions of the unobservable central fibres from observations made on a digital image of the thick fibres. For central fibres, the relation between the rose of directions and the point intensity, observed on a sampling line, is known. We derive, under regularity conditions, the relation between the unobservable point intensity and the scaled variogram observed on the line in a binary and a greyscale image. Using such a relation, it is possible to draw inference…
Telpiskās statistikas metodes programmā R
2015
Bakalaura darbā aplūkota programmas R veiktspēja apstrādāt, analizēt un attēlot telpiska veida datus. Aprakstīti telpisko datu veidi, kā arī to struktūra programmā R. Veikts ieskatas telpiskajos punktu modeļos, kā arī telpiskajā autokorelācijā un interpolācijā. Paņemti dati no Latvijas meteroloģijas centra par relatīvo mitrumu vairākās stacijās. Izpētīta to autokorelācija ar variogrammas palīdzību. Meklēts labākais modelis empīriskajai variogrammai, kā arī veikta interpolācija pēc vairākām metodēm (Tīsena poligonu, inversā attāluma un parastā kriginga) lai iegūtu vērtības vietās, kur mērījumi netika veikti. Tika secināts, ka programma R ir ļoti kompetenta darbībai ar telpiskajiem datiem, re…
Geostatistics for Mapping Leaf Area Index over a Cropland Landscape: Efficiency Sampling Assessment
2010
This paper evaluates the performance of spatial methods to estimate leaf area index (LAI) fields from ground-based measurements at high-spatial resolution over a cropland landscape. Three geostatistical model variants of the kriging technique, the ordinary kriging (OK), the collocated cokriging (CKC) and kriging with an external drift (KED) are used. The study focused on the influence of the spatial sampling protocol, auxiliary information, and spatial resolution in the estimates. The main advantage of these models lies in the possibility of considering the spatial dependence of the data and, in the case of the KED and CKC, the auxiliary information for each location used for prediction pur…