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SWATOnline Web-based Decision Support Tool

​SWATOnline is a web application developed for hydroclimatic application to leverage data sharing capabilities employing current web technologies.  The SWATOnline web app can be duplicated, installed, and hosted anywhere.  The work presented in this web app represents an effort to lower technical barriers for the Soil and Water Assessment Tool (SWAT) model through using open source web development, web services, and cloud storage technologies.

Figure 1.  The SWATonline data viewer home view excerpted from (McDonald et al., 2019)§. The SWATonline uses the SWAT model shapefiles (e.g., stream network, sub-basin) along with the Microsoft® Bing™ Maps Platform APIs for enhanced querying and visualizing the SWAT model input and output data products.  The lower Mekong River Basin SWAT model data (Mohammed et al., 2018)* has been used here as an input to elucidate the SWATonline web app capabilities.  The SWATonline related source code and documentation is available online at


§McDonald, S., Mohammed, I.N., Bolten, J.D., Pulla, S., Meechaiya, C., Markert, A., Nelson, E.J., Srinivasan, R., Lakshmi, V.

Web-based decision support system tools: The Soil and Water Assessment Tool Online visualization and analyses (SWATOnline) and NASA earth observation data downloading and reformatting tool (NASAaccess)

Environmental Modelling and Software, Volume 120, October 2019


*I.N. Mohammed, J. Bolten, R. Srinivasan, V. Lakshmi

Improved hydrological decision support system for the Lower Mekong River Basin using satellite-based earth observations

Remote Sens., 10 (2018), p. 885

NASAaccess: Downloading and reformatting tool for NASA Earth observation data products


NASAaccess is a software application in the form of a R package ( and a web application.  The NASAaccess software tool streamlines the retrieval and processing of the global National Aeronautics and Space Administration (NASA) earth observation data products (e.g., GPM and GLDAS) for use in hydrological models.  Tne NASAaccess software can generate gridded ascii tables of climate (CIMP5) and weather data (GPM, TRMM, GLDAS) needed to drive various hydrological models (e.g., SWAT, VIC, RHESSys, ...etc.).  

The NASAaccess web application has been developed to lower the technical barrier that was keeping interested parties from accessing the powerful capabilities of the NASAaccess package and, ultimately, the information available in the NASA observation datasets. The NASAaccess web interface frees users from needing any technical background in R package or earth observation data processing, yet still allows them to process large amounts of data into small, more manageable data files.


Figure 2.  The NASAaccess web app user interface excerpted from (McDonald et al., 2019)§.

Figure 3.  NASAaccess R package index page.  The NASAaccess R package is an open source software package under NASA Open Source Agreement v1.3 ( and can be downloaded from Github at  More details on installing the package can be accessed at