Geospatial data resampling and resolution effects on watershed modeling: A case study using the agricultural non-point source pollution model

E. Lynn Usery, Michael P. Finn, Douglas J. Scheidt, Sheila Ruhl, Thomas Beard, Morgan Bearden

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)

Abstract

Researchers have been coupling geographic information systems (GIS) data handling and processing capability to watershed and waterquality models for many years. This capability is suited for the development of databases appropriate for water modeling. However, it is rare for GIS to provide direct inputs to the models. To demonstrate the logical procedure of coupling GIS for model parameter extraction, we selected the Agricultural Non-Point Source (AGNPS) pollution model. Investigators can generate data layers at various resolutions and resample to pixel sizes to support models at particular scales. We developed databases of elevation, land cover, and soils at various resolutions in four watersheds. The ability to use multiresolution databases for the generation of model parameters is problematic for grid-based models. We used database development procedures and observed the effects of resolution and resampling on GIS input datasets and parameters generated from those inputs for AGNPS. Results indicate that elevation values at specific points compare favorably between 3- and 30-m raster datasets. Categorical data analysis indicates that land cover classes vary significantly. Derived parameters parallel the results of the base GIS datasets. Analysis of data resampled from 30-m to 60-, 120-, 210-, 240-, 480-, 960-, and 1920-m pixels indicates a general degradation of both elevation and land cover correlations as resolution decreases. Initial evaluation of model output values for soluble nitrogen and phosphorous indicates similar degradation with resolution.

Original languageEnglish
Pages (from-to)289-306
Number of pages18
JournalJournal of Geographical Systems
Volume6
Issue number3
DOIs
Publication statusPublished - Oct 2004
Externally publishedYes

ASJC Scopus Subject Areas

  • Geography, Planning and Development
  • Earth-Surface Processes

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