A geostatistical approach for modelling and combining spatial data with different support

The paper proposes a geostatistical framework to solve the issues of heterogeneous support for spatial estimation. Apparent soil electrical conductivity (ECa) was measured in a field cropped with San Marzano tomato using a multiple frequency electromagnetic profiler with 6 operating frequencies. Mixed support kriging was used to estimate ECa taking into account the change of support. The method includes punctual kriging with the error being the dispersion variance associated with each frequency. The individual ECa maps were weighted by the dispersion variance to obtain a map which was used for field partition in management zones.

GEOSTATISTICAL MODELING OF TIMBER VOLUME SPATIAL VARIABILITY FOR Tectona grandis L. F. PRECISION FORESTRY

ABSTRACT Considering the hypothesis that the wood volumes present spatial dependence, whose knowledge contributes for the precision forestry, the aim of this work was to estimate the volume spatial variability for timber assortments and identify their spatial patterns on Tectona grandis stands. A dataset of 1,038 trees was used to fit taper models and estimate the total stem, sawlog, and firewood volumes in 273 plots allocated on T. grandis stands at eight years old, which represents the second thinning that enables commercial volumes. Semivariograms models was applied to fit the spatial dependence, and punctual kriging was used to compose volume maps. Geostatistical modeling allowed us to estimate the T. grandis spatial variability and develop timber volume maps. Thus, silvicultural treatments, such as thinning and pruning, as well as for planning spatial interventions, are possible to be recommended for aimed wood products.

APLIKASI KONSEP KRIGING PADA DATA SIMULASI GANGGUAN GEOMAGNET LOKAL

Makalah ini membahas aplikasi konsep Kriging pada data simulasi gangguan geomagnet lokal dari 3 (tiga) stasion geomagnet (SG). Konsep ini asal mulanya dari geostatistik dan sekarang digunakan secara luas dalam analisis spasial. Metode ini juga dikenal sebagai regresi proses Gauss, prediksi Kolmogorov-Wiener atau prediksi ketakbiasan linier terbaik. Tujuan penulisan makalah ini adalah untuk melakukan estimasi atau interpolasi gangguan geomagnet di sekitar tiga stasion geomagnet (lokasi observasi) tersebut. Untuk merealisasikan tujuan di atas ini mengunakan metode punctual kriging. Kontribusi hasil estimasi atau interpolasi gangguan geomagnet ini nantinya digunakan sebagai dasar pembuatan peta atau kontur gangguan geomagnet di sekitar ketiga lokasi observasi tersebut. Dengan demikian informasi gangguan geomagnet akan berguna dalam survei geologi di sekitar lokasi pengamatan. Kata kunci : Konsep kriging, data simulasi, gangguan geomagnet lokal This paper discuss about the application of Kriging concept on simulation data of local geomagnetic disturbance at three geomagnet stations (SG). This concept was derived from geostatistic and now it is widely used in spatial analysis. This method is also well known as Gaussian process regression, Kolmogorov-Wiener prediction or Best Linear Unbiased Prediction. The aim of this paper is to estimate or interpolate the geomagnetic disturbances at three observation locations. In order to realize the above purpose, it uses punctual kriging method. The contribution of estimation result of this geomagnetic disturbances will be used as a basic for contour mapping of geomagnetic disturbance around these three observation locations. Hence, the information of these geomagnetic disturbances will be useful for geological survey around observation locations. Keywords: Kriging concept, simulation data, local geomagnetic disturbance

Land suitability assessment in the Namoi Valley of Australia, using a continuous model

In an agricultural context, land evaluation is assessment for a specified kind of land utilisation. The final result of agricultural evaluation is a map, which partitions the landscapes into suitable and unsuitable areas for a particular land-use of interest. However, this approach may not represent the continuity of land. Land suitability could be better expressed by a fuzzy approach. In this paper a fuzzy methodology is used to evaluate land suitability in the Edgeroi district for various crops including barley, dryland cotton, oats, pasture, soybean, sorghum, sunflower, and wheat. This is achieved using a membership function to derive a land-suitability membership score ranging from non-suitable (i.e. 0) to suitable (i.e. 1). We express this as continuous land suitability maps using punctual kriging. An expression for overall land suitability (i.e. its versatility) and its capacity with respect to suitability to particular rotations is introduced to highlight the most productive units of soil.