News Flash

SLAMM-View now presents two types of predictions from studies of sea-level rise on coastal wetlands: "regional" and "site-specific". Up to this point in time, only SLAMM output from regional simulations have been available: for the Chesapeake, Georgia / South Carloina, and Puget Sound / Northwest Coast study regions. Recently, site-specific results for the Chincoteague National Wildlife Refuge and surrounding area have been made available through SLAMM-View. Note that although the entire Chincoteague study site lies within the Chesapeake study region, the results from the site-specific study originate from completely separate model runs. We anticipate additional site-specific results to be available later this year. To see the new Chincoteague results, go to http://www.slammview.org/chincoteagueVA/.

Background

Efficiently and effectively presenting the large volume of geospatially-referenced, gridded data output from the Sea Level Affects Marshes Model (SLAMM) for each sea-level rise (SLR) scenario time-series is a challenge. For most studies, an output file is produced for each of 5 different dates in a time-series (i.e., Base Year, 2025, 2050, 2075, and 2100) for each different scenario of sea level rise (e.g., IPCC A1B Mean, IPCC A1B Max, and 1m). When examining these outputs, interested parties logically most often want to view two types of combinations of these 15 different data layers: "same scenario, different date", and "same date, different scenario", which in sum result in 45 unique pairs of simulation output.

While summary tables provide the means to present SLAMM output in a condensed form, the spatial context of where the changes occur is lost. Maps of the entire study region displayed at a resolution sufficient to examine local impacts are large and unwieldy to place side by side for comparison, especially in digital format. Making the raw, gridded output data publicly-available is not a viable solution for the researcher or layperson lacking GIS skills, GIS software, or persons with those resources but lacking time.

Image Matters LLC developed the initial version of the "SLAMM-View" web-mapping application to solve this geospatial accessibility problem. SLAMM-View portrays pairs of simulation results in conjunction with other thematic layers which provide context. SLAMM-View allows the user to choose one of the 45 output pairs in a dual "live" map display: either from the same year (e.g., 2100) but from different scenarios (e.g., a 0.5 m SLR and a 1 m SLR), or from different years within the same scenario (e.g., base year 2000 and year 2100, both under a 1 m SLR). The zooming and panning tools allow the user to focus the inquiry on their particular locality of interest, be it a large region encompassing the entire Georgia coastline, or a small barrier island. One unique aspect of this web-mapping tool, vital to facilitating a comparison between the selected pair of simulation results, is that the dual maps are geographically-linked: zooming or panning in one map causes an identical action in the other map.

SLAMM-View is a browser-based application that utilizes a combination of server and client software (Java and Java-script) based on Image Matters' userSmarts® technology. The ACSII formatted output was converted to PNG (Portable Network Graphics), an extensible file format for the lossless, portable, well-compressed storage of raster images. This provides for fast rendering of the large gridded maps over the Internet without any reduction in the detail when viewed at local scales. The application accesses contextual layers such as state and county boundaries, roads, and NWI wetlands via web mapping services (OGC WMS), with adjustable layer transparency and a layer control view that allows users to order and turn these ancillary layers on and off. SLAMM-View was developed to support Firefox, as well as both Internet Explorer 6 and 7 browsers. SLAMM-View is currently at Version 1.1.

U. S. Fish and Wildlife Service is supporting SLAMM-View's current availability and its future enhancements. Development of the initial version of SLAMM-View was funded by an EPA STAR grant that examined the Effect of Sea Level Rise and Climate Variability on Ecosystem Services of Tidal Marshes on the Georgia / South Carolina coast.

SLAMM-View presently provides access to the digital geospatial data results from SLAMM simulations run for three projects:

• Georgia / South Carolina project
• Chesapeake project
• Puget Sound project

Note that the "base year" or initial condition for the model runs as defined by the US Fish and Wildlife Service's National Wetland Inventory maps (NWI) is 1999 for the Georgia / South Carolina project, 1996 for the Chesapeake project, and range from 1977 to 1990 for the 11 Puget Sound sites. In this implementation of SLAMM-View, simulation results from three sea level rise (SLR) scenarios are presented:

• "Scenario 1" or "S1" = Intergovernmental Panel on Climate Change (IPCC) Scenario A1B Mean; 39 cm of global average SLR, adjusted for local conditions.
• "Scenario 2" or "S2" = IPCC Scenario A1B Maximum; 69 cm of global average SLR, adjusted for local conditions.
• "Scenario 3" or "S3" = a global 1-meter eustatic SLR, adjusted for local conditions.

Getting Started

SLAMM-View can be accessed at http://www.slammview.org/slamm-view/.

The SLAMM-View GUI, displayed below, is composed of 6 component "views":

• Compare View - contains dual, geographically-linked map views and map tools for examining the different paired SLAMM output combinations.
• Comparisons View - displays a list of all available SLAMM output pairs, and describes the type of comparison for each pair. By clicking on the output pair of interest (a row in the table), that pair is selected and then portrayed in the maps in the Compare View.
• Layers View - displays a list of all layers available for portrayal on the dual maps in the Compare View, with checkbox controls for turning layer visibility on and off. Layers are selected by clicking on the layer of interest (a row in the table). Once a layer is selected, its order can be changed using the controls available in pulldown menu accessed through the icon found in the upper right corner of the view.
• Regions View - provides a hierarchy of project regions which may be used to quickly focus the map to a specific region's extent. To zoom to a region, click on the region of interest and press the "Zoom" button. Note: the "Zoom" button is only active for regions and not region folders.
• Legend View - a color key to the standard SLAMM cover categories portrayed on the maps, with the capability to open the legend image in a separate popup window.
• Selected Layer View - describes the selected layer, and provides transparency control by clicking at the desired point along the 0 to 1 opacity continuum line.

Note that the Comparison View is co-located with the Layers View, and the Regions, Legend, and Selected Layer Views are co-located. You can toggle between co-located views by clicking the names in the headers.

HELP is found by clicking the Help icon in the Map Toolbar, or the labeled icon in upper right corner of the GUI.

There are two simple steps in getting started with SLAMM-View:

1) Select a Comparison of interest by clicking on the row in the list in the Comparison View.

There are 45 unique combinations, or pairs, from 3 different scenarios each with 5 different dates:

• 15 combinations of same date, different scenario
• 30 combinations of same scenario, different date

When selected (as appears above):

1. A combination (the selected row in the list) will be highlighted in blue, and
2. Two sets of SLAMM output data from the selected pair will populate the Map Views.

2) Zoom to your area of interest using the Regions View, and then Pan and Zoom using the Map Tools in the Map View header.

1. Click to highlight a Project Area, Coastal Barrier Resources Act (CBRA) Unit, or National Wildlife Refuge.
2. Zoom to the selected region of interest by clicking on the Zoom button, as shown below:

3. Then Pan and Zoom by clicking to "depress" the tool button of choice to activate the tool, then use the tool. Note that a tool stays active until you deactivate it or activate another tool.

To view the map legend:

1. Switch to the Legend View.

2. Open the legend in a new window (as shown below) by clicking on the Popup button (visible above).

To turn contextual layers on or off, or change the order of layers in the Map View, use the controls available from within the Layers View:

1. Click on the Layers View header to switch from the Comparison View.
2. Select the layer by clicking on the row in the list presented in the Layers View (as shown below)
3. Check (or uncheck) the leftmost "Viz" box to turn on (or off) the selected layer.
4. To access the list of layer controls, click on the menubar toggle , as shown in the image below.

NOTE: Any SLAMM comparison that you select (e.g., S3 Base vs S3 2100) from the Comparisons View, becomes a configurable layer named “SLAMM Layers” that appears at the bottom of the list in the Layers View.

To change the opacity setting for a layer in the Selected Layer View:

1. Select the layer as in step 2, above.
2. Click on the Selected Layer View header to switch from the Legend View.
3. Click on and drag the Opacity Level Bar to change from the 1.00 default value to the desired opacity level.

Bibliography

The SLAMM-View bibliography can be accessed here.

Feedback

We would appreciate your feedback about the SLAMM-View web mapping application: