U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2004-3111

October 2004

User Interface for ATLSS Models

Printed on recycled paper

The U.S. Geological Survey (USGS) Across Trophic Level 

System Simulation (ATLSS) Program model interface, developed through the assistance of the National Science Foundation 

(NSF), provides a convenient means for natural resource managers to use the ATLSS high-performance ecological modeling 

package on their individual personal computers. This product 

was developed to provide an intuitive interface for model 

modification, while removing the burden of model software and 

hardware management and acquisition.

The development of ecological models as useful tools in 

ecological restoration has increased during the last few decades. 

However, such models are not always effectively used at 

the resource manager level. This can be traced to the lack of 

training, time, and resources needed to implement and run the 

models. The ATLSS model interface is a means of removing 

some of these impediments and providing an intuitive interface 

to the resource manager. This will become a larger issue as 

models become more complex and the computational demands 

require more advanced computing resources. The ATLSS model 

interface is a software tool for addressing the growing need 

to supply high-performance computational models and the 

resources needed for their effective use by the decision-making 

community.

How Does the ATLSS Model Interface Work?

The ATLSS model interface needs to satisfy 

two main criteria in providing a flexible means 

of hosting high performance models. The first is 

to provide access to the computational resources 

needed to run each of the models in the ATLSS 

suite. This requires access to hardware, such as 

computing clusters and software resources. The 

second criterion is to provide an intuitive interface 

that is easily accessible.

The computational platform used in the model 

interface is the Scalable Intracampus Research 

Grid (SINRG) supported by the NSF. The SINRG 

project provides access to research clusters and 

computers for interdisciplinary research using the 

emerging national research grid. The NetSolve 

and Internet Backplane Protocol (IBP) were 

deployed on the SINRG research grid and used to 

provide the access needed to allow implementation of the ATLSS ecological models. NetSolve is 

a remote-procedure call-based package that allows 

users to access a wide variety of hardware and 

software resources through a controlled interface 

without the need for individual user privileges. 

This allows us to provide access to several research grids that 

would otherwise be cumbersome or impossible to access. 

Because the model runs are being performed remotely, a method 

to move and manage the large hydrologic input files and output 

data was required and realized through the use of IBP. Through 

the use of a small ASCII key called an exnode, terabytes of disk 

storage become available for the transfer and short-term storage 

of files and data. Combining these two resources (fig. 1) allows 

the ATLSS model interface to transport large input files to a 

remote computer, perform a model run, and return large output 

files in a manner that maintains a secure environment for the 

remote system.

Using the Model Interface on the Web

Various agencies expressed an interest in a single portal for 

access to the models with execution and data-retrieval capabilities. A web interface (the part of the model interface that the 

user sees and interacts with) is a natural means to provide a 

universal cross-platform interface. The web interface can act as 

a configurator for model runs and an initiator of the grid-based 

ATLSS model runs. The resulting output can then be tabulated 

and displayed so that initial and subsequent users can access the 

data. Upon retrieval of the model run data, a pre-existing Geographic Information System (GIS) visualization and analysis 

Figure 1. Architecture of the grid interface. The "grid" refers to the set of computer systems that are 

networked together to run and the several ATLSS models. The two "Model 1" boxes show different 

implementations of the same ATLSS model within the computer grid. Dedicated

Web Interface

Results

Repository

Job

Scheduler

Model 1

Model 2

Model 3

Model n

Simulation Moderator

Remote

User

Remote

User
• Allows for the sharing of model runs performed by other 

users, removing the need for duplication of runs, which 

save time and resources for the manager; and

• Provides flexibility in the platform upon which the models 

natively run. Microsoft Windows, Linux, OS X, and 

SOLARIS operating system models can be incorporated 

side by side in the interface, creating an all-inclusive 

modeling resource.

As grid computing resources become more sophisticated 

and the complexity of ecological models increases, the ATLSS 

model interface will be an invaluable tool in allowing complex 

ecological models to be used as a tool by resource managers.

Acknowledgments

This research has been supported by the National Science 

Foundation under grant No. DEB-0219269. Used were the 

resources of the Scalable Intracampus Research Grid (SInRG) 

Project at the University of Tennessee, supported by the 

National Science Foundation CISE Research Infrastructure 

Award EIA-9972889.

For further information:

Louis J Gross, Mark Palmer, and Eric Carr

The Institute for Environmental Modeling

University of Tennessee

Knoxville, Tennessee 37996

gross@tiem.utk.edu palmer@tiem.utk.edu 

carr@tiem.utk.edu

Donald L. DeAngelis

USGS Florida Integrated Science Center 

Water and Restoration Studies

University of Miami

Coral Gables, FL 33124

ddeangelis@umiami.ir.miami.edu

Figure 3. Output from the ATLSS Long-Legged Wading Bird Model.

tool, the ATLSS Data Viewer, can be used 

to examine the output data. A login control 

was implemented within the interface to 

maintain a level of appropriate use without 

the problems associated with a completely 

public system. This is critical for model 

runs that require extended time periods 

to perform and use multiple computer 

resources.

A typical utilization of the ATLSS web 

interface is shown in figure 2. A user logs 

into the interface and selects the desired 

model to be run. The hydrologic scenario is 

then chosen, and the configuration parameters are varied as needed for the model 

run. Upon initiating the run, a Run ID 

number is provided, and the user is informed by email when the 

run is complete. Most runs take at least 3 hours (some are much 

longer) depending on parameter settings. The email provides 

a link to the output page where a user can reference a run by 

the Run ID and also browse previously run scenarios. Each run 

of the model is referenced in a table that includes the hydrologic scenario and parameter fields associated with that model. 

Depending upon the model selected, various forms of output are 

supplied with formatted input files for the ATLSS data viewer 

(fig. 3). 

Advantages of the ATLSS Model Interface

In summary, the ATLSS model interface:

• Provides access to models for a wide range of resources 

for the manager in many locations;

• Removes the need for technical skills to install, manage, 

and run the model code, support files, and software;

• Removes the need for hardware capabilities to run the 

various models by using research grid computers, thereby 

providing a valuable resource that otherwise would be 

unusable by the resource manager;

Figure 2. ATLSS Model Interface.