Accounting for and Predicting the Influence of Spatial Autocorrelation in Water Quality Modeling

Several studies in the hydrology field have reported differences in outcomes between models in which spatial autocorrelation (SAC) is accounted for and those in which SAC is not. However, the capacity to predict the magnitude of such differences is still ambiguous. In this study, we hypothesized tha...

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Main Authors: Lorrayne Miralha, Daehyun Kim
Format: Article
Language:English
Published: MDPI AG 2018-02-01
Series:ISPRS International Journal of Geo-Information
Subjects:
Online Access:http://www.mdpi.com/2220-9964/7/2/64
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author Lorrayne Miralha
Daehyun Kim
author_facet Lorrayne Miralha
Daehyun Kim
author_sort Lorrayne Miralha
collection DOAJ
description Several studies in the hydrology field have reported differences in outcomes between models in which spatial autocorrelation (SAC) is accounted for and those in which SAC is not. However, the capacity to predict the magnitude of such differences is still ambiguous. In this study, we hypothesized that SAC, inherently possessed by a response variable, influences spatial modeling outcomes. We selected ten watersheds in the USA and analyzed if water quality variables with higher Moran’s I values undergo greater increases in the coefficient of determination (R2) and greater decreases in residual SAC (rSAC). We compared non-spatial ordinary least squares to two spatial regression approaches, namely, spatial lag and error models. The predictors were the principal components of topographic, land cover, and soil group variables. The results revealed that water quality variables with higher inherent SAC showed more substantial increases in R2 and decreases in rSAC after performing spatial regressions. In this study, we found a generally linear relationship between the spatial model outcomes (R2 and rSAC) and the degree of SAC in each water quality variable. We suggest that the inherent level of SAC in response variables can predict improvements in models before spatial regression is performed.
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spelling doaj.art-69b2099f95ac4489a564862eece3470b2022-12-22T03:51:55ZengMDPI AGISPRS International Journal of Geo-Information2220-99642018-02-01726410.3390/ijgi7020064ijgi7020064Accounting for and Predicting the Influence of Spatial Autocorrelation in Water Quality ModelingLorrayne Miralha0Daehyun Kim1Department of Geography, University of Kentucky, Lexington, KY 40508, USADepartment of Geography, Seoul National University, Seoul 08826, KoreaSeveral studies in the hydrology field have reported differences in outcomes between models in which spatial autocorrelation (SAC) is accounted for and those in which SAC is not. However, the capacity to predict the magnitude of such differences is still ambiguous. In this study, we hypothesized that SAC, inherently possessed by a response variable, influences spatial modeling outcomes. We selected ten watersheds in the USA and analyzed if water quality variables with higher Moran’s I values undergo greater increases in the coefficient of determination (R2) and greater decreases in residual SAC (rSAC). We compared non-spatial ordinary least squares to two spatial regression approaches, namely, spatial lag and error models. The predictors were the principal components of topographic, land cover, and soil group variables. The results revealed that water quality variables with higher inherent SAC showed more substantial increases in R2 and decreases in rSAC after performing spatial regressions. In this study, we found a generally linear relationship between the spatial model outcomes (R2 and rSAC) and the degree of SAC in each water quality variable. We suggest that the inherent level of SAC in response variables can predict improvements in models before spatial regression is performed.http://www.mdpi.com/2220-9964/7/2/64spatial autocorrelationwater qualityspatial modelingcoefficient of determinationresidual autocorrelation
spellingShingle Lorrayne Miralha
Daehyun Kim
Accounting for and Predicting the Influence of Spatial Autocorrelation in Water Quality Modeling
ISPRS International Journal of Geo-Information
spatial autocorrelation
water quality
spatial modeling
coefficient of determination
residual autocorrelation
title Accounting for and Predicting the Influence of Spatial Autocorrelation in Water Quality Modeling
title_full Accounting for and Predicting the Influence of Spatial Autocorrelation in Water Quality Modeling
title_fullStr Accounting for and Predicting the Influence of Spatial Autocorrelation in Water Quality Modeling
title_full_unstemmed Accounting for and Predicting the Influence of Spatial Autocorrelation in Water Quality Modeling
title_short Accounting for and Predicting the Influence of Spatial Autocorrelation in Water Quality Modeling
title_sort accounting for and predicting the influence of spatial autocorrelation in water quality modeling
topic spatial autocorrelation
water quality
spatial modeling
coefficient of determination
residual autocorrelation
url http://www.mdpi.com/2220-9964/7/2/64
work_keys_str_mv AT lorraynemiralha accountingforandpredictingtheinfluenceofspatialautocorrelationinwaterqualitymodeling
AT daehyunkim accountingforandpredictingtheinfluenceofspatialautocorrelationinwaterqualitymodeling