Spatial variability occurs when a quantity that is measured at different
spatial locations exhibits values that differ across the locations. Spatial variability can be assessed using
spatial descriptive statistics such as the
range
Range may refer to:
Geography
* Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra)
** Mountain range, a group of mountains bordered by lowlands
* Range, a term used to i ...
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Let us suppose that the Rev' z(x) is perfectly known at any point x within the field under study. Then the
uncertainty
Uncertainty refers to epistemic situations involving imperfect or unknown information. It applies to predictions of future events, to physical measurements that are already made, or to the unknown. Uncertainty arises in partially observable or ...
about z(x) is reduced to zero, whereas its spatial variability still exists. Uncertainty is closely related to the amount of spatial variability, but it is also strongly dependent upon sampling.
Geostatistical
Geostatistics is a branch of statistics focusing on spatial or spatiotemporal datasets. Developed originally to predict probability distributions of ore grades for mining operations, it is currently applied in diverse disciplines including petr ...
analyses have been strictly performed to study the spatial variability of pesticide sorption and degradation in the field. Webster and Oliver provided a description of geostatistical techniques. Describing uncertainty using geostatistics is not an activity exempt from uncertainty itself as
variogram
In spatial statistics the theoretical variogram 2\gamma(\mathbf_1,\mathbf_2) is a function describing the degree of spatial dependence of a spatial random field or stochastic process Z(\mathbf). The semivariogram \gamma(\mathbf_1,\mathbf_2) is ...
uncertainty may be large and
spatial interpolation
In numerical analysis, multivariate interpolation is interpolation on functions of more than one variable; when the variates are spatial coordinates, it is also known as spatial interpolation.
The function to be interpolated is known at given poi ...
may be undertaken using different techniques.
References
Literature
* Isaaks, E.H., Srivastava R.M.: Applied Geostatistics. 1989
* Fortin, Marie-Josee, Dale, Mark.: Spatial Analysis A Guide for Ecologists. 2005. Cambridge University Press, 365 pp.
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External links
* {{cite web , title=EPA Regional Vulnerability Assessment (ReVA) Environmental Decision Toolkit , website=amethyst.epa.gov , date=2006-10-01 , url=http://amethyst.epa.gov/revatoolkit/Definitions.jsp , archive-url=https://web.archive.org/web/20061001123614/http://amethyst.epa.gov/revatoolkit/Definitions.jsp , archive-date=2006-10-01 , url-status=dead , ref={{sfnref , amethyst.epa.gov , 2006 , access-date=2021-04-12
*http://gis.esri.com/library/userconf/proc05/papers/pap1184.pdf
*https://web.archive.org/web/20100110102738/http://willingtoncropservices.co.uk/case_study_GPS-soil-sampling-nutrient-mapping.htm Willington Crop Services shows spatial variability in action with Case Study on GPS soil sampling, GPS nutrient mapping and nutrient management.
Spatial analysis