Back to top

Setting Up GNOME for Your Region

When you run the GNOME spill trajectory model in its Standard Mode, you need to use a Location File. Location Files contain generalized information about the tides, currents, and shorelines for a particular place. If a Location File is not available for your region of interest, you can make your own file to set up GNOME for your region. (However, be forewarned that creating these files requires regional physical oceanographic expertise.) Most people who make these files generally use GNOME's Diagnostic Mode to make a Diagnostic "Save File," rather than a Location File. (Unless you plan to market a Location File, you can put all the same physics in a Save File without having to construct the Wizard expert system or the dialog boxes.) Once you have created the Save File, you can then use this file to model potential spills in your area. To build the Save File, you'll need the following components:

  • a vector map of the shoreline.
  • a hydrodynamic model output for the currents.
  • an estimate of the eddy mixing.
  • a wind forecast.
Getting the "Goods"

We've created an online tool called GOODS (GNOME Online Oceanographic Data Server) that helps you access publicly available base maps, ocean currents, and winds from various models and data sources. You can then download the files in appropriate formats that can be read directly into GNOME.

In GOODS, the world shoreline is available; however, the wind and current data are more limited. You can get the latest input/output data formats and the GNOME format documentation on the GNOME Technical Documentation page.

Example data files are discussed in the documentation and are available for both Windows and Mac operating systems. Once you've unzipped the data files, look for the folder, Data Files in Format Document, on your desktop. You can then open the files in a text editor or in GNOME. MOSS file format information is available in the following NOAA HAZMAT Report: Digital Distribution Standard for NOAA Trajectory Analysis Information [PDF, 225.5 KB]. See Appendix A of the report for the MOSS standard input file format.

Getting a Shoreline Map

In GOODS, in the Base Maps section, click the link, Custom map generator. On this page, you will extract coastline data from the GSHHS Database and convert them to GNOME compatible (BNA) format. Enter decimal lat/long boundaries for your region (or use the Google Maps rectangle selector tool), choose a resolution, then click Get Map. Save the shoreline file to a selected folder/directory to load into GNOME.

Getting Currents

GOODS offers currents from global and regional ocean current models, as well as measured currents from several sources. After you've selected which global or regional model covers your area of interest, you'll be able to subset the model output to fit your needs. Enter decimal lat/long boundaries for your region (or use the Google Maps rectangle selector tool) and choose a time range. Click the button, Update dimensions, to see the size of the dataset you will be downloading. When you are satisfied with your selection, click the button, Get Data. Save the currents file to a selected folder/directory to load into GNOME.

Getting Winds

GOODS offers wind observations from the NOAA National Data Buoy Center (the prior 45 days) and gridded forecasts from several models. To determine the station ids for any buoys in your area of interest, visit the National Data Buoy Center website. If you choose to use gridded forecasts, you'll be able to subset the model output to fit your needs. Enter decimal lat/long boundaries for your region (or use the Google Maps rectangle selector tool) and choose a time range. Click the button, Update dimensions, to see the size of the dataset you will be downloading. When you are satisfied with your selection, click the button, Get Data. Save the winds file to a selected folder/directory to load into GNOME.

Loading the "Goods" into GNOME

First, you'll need to change to GNOME's Diagnostic Mode. Under the File menu, choose Preferences. On the Mode tab, under Model Mode, select Diagnostic.

Loading your Shoreline Map

In GNOME, in the Summary List to the left of the map, double-click Map. In the dialog box that opens, click Load and select the file you saved in GOODS. If the map doesn't display properly at first, try zooming until the map appears.

Adding Currents as a Mover

In GNOME, in the Summary List to the left of the map, double-click Universal Movers. In the dialog box that opens, select Currents from the drop-down menu. Click Load, then select the file you saved in GOODS.

Adding Winds as a Mover

In GNOME, in the Summary List to the left of the map, double-click Universal Movers. In the dialog box that opens, select either Winds-Variable or Winds-Constant from the drop-down menu. Click Load, then select the file you saved in GOODS.

More Information about Setting Up GNOME

GNOME References: Find references for some of GNOME's methods and uses.

Questions: Contact the GNOME Wizard with your questions: A reply may not be immediate due to spill response and other duties taking precedence.

Last updated Friday, July 31, 2020 11:36am PDT