MARPLOT Software

On this sample MARPLOT map, a point object (a hospital) has been drawn on the map and a tricolored ALOHA threat zone estimate is also displayed. The Google Streets basemap is the background image of the map.

MARPLOT is the mapping program for the CAMEO software suite, which is used widely to plan for and respond to chemical emergencies.  Learn more about the CAMEO software suite.

MARPLOT’s easy-to-use GIS interface allows you to add objects to a map, as well as view and edit data associated with the objects.  You can choose between several background basemap images, and you can customize your map further with annotations and online layers from Web Mapping Services. You can also interact with the map in other ways, such as getting population estimates within an area.  MARPLOT can be run by itself as a general mapping program.  It can also be used interactively with programs in the CAMEO suite to display ALOHA threat zone estimates on the map or to link map objects to database records in CAMEOfm.

Downloading MARPLOT

  • Download MARPLOT Installer for Windows (Version 5.0.1, Mar 2015, 178 MB EXE)
    Use the full installer if you are a new MARPLOT user, or if you are using a version prior to 5.0.
  • Download MARPLOT Updater for Windows (Version 5.0.1, Mar 2015, 1.3 MB EXE)
    Use the updater if you are using MARPLOT 5.0, and you want to update to the new version and keep your current data.
  • Download MARPLOT for Mac  (Version 5.0.1, Mar 2015, 391 MB DMG); see instructions for latest Max OS X versions

    Note: The Mac version is only available as a full installer.  If you are already running MARPLOT 5.0, you need to be careful when installing version 5.0.1 so that you don't lose your current data.  Before installing, rename your existing MARPLOT folder (typically inside the Applications folder) to a different name.  Then, install version 5.0.1.  Finally, open the new MARPLOT folder, delete the MARPLOT Data folder that is inside, and copy in your old MARPLOT Data folder as a replacement.  Then you can start your new MARPLOT 5.0.1 version, and it will have all of your current data.

The Windows version can be run on Windows XP, Vista, 7, and 8 operating systems.  The Macintosh version can be run on Lion (10.7.x), Mountain Lion (10.8.x), Mavericks (10.9.x) and Yosemite (10.10.x) operating systems.  Operating systems not listed here have not been tested and are not supported. 

Important Note for Current MARPLOT 4.x and 3.x Users: Read the instructions for upgrading to MARPLOT 5.x to ensure that your data is successfully transferred to the new version.

Learning More About MARPLOT

For a brief summary of the MARPLOT program and its capabilities, download the MARPLOT fact sheet (PDF). (2 pp, 712 KB, About PDF

The MARPLOT 5 series includes four U.S. boundaries layers and some online Web Mapping Service (WMS) layers. You can add additional object-based layers, WMS layers, and raster map images from other sources; refer to this list of national geospatial data sources for some examples. 

What is new in latest versions of MARPLOT (5.0 and 5.0.1)?

  • Completely redesigned program (v 5.0)
  • Expanded basemap options with global map coverage (v 5.0)
  • Enhanced GIS capabilities with new data management options in the program and data fields now included during import (v 5.0)
  • Added auto-plot feature to easily create linked MARPLOT objects for CAMEO records with latitude/longitude values (v 5.0)
  • Added U.S. National Grid coordinates (in addition to latitude/longitude coordinates) (v 5.0)
  • Added ability to add custom symbols (v 5.0)
  • Re-established support for the Mac operating system, so that both Mac and Windows users can run the latest version (v 5.0)
  • Fixed bug where MARPLOT files could get out of sync when a user had a layer with objects in individual graphics mode, then switched the layer to common graphics mode and added an object.  This bug would result in several error messages appearing in MARPLOT.  The fix prevents this issue from happening to layers in 5.0.1, and it also fixes the problem on any out-of-sync layer (from 5.0) the next time an object is added to the layer. (v 5.0.1)
  • Fixed bug where images for object and layer popup notes were not included in MPZ export files. (v 5.0.1)
  • Fixed bug where taking screenshots did not work on the Lion operating system. (v 5.0.1)
  • Fixed several other small bugs and made minor program improvements, primarily to the way files are imported. (v 5.0.1)

Note: We recommend upgrading to MARPLOT 5.0.1.  However, MARPLOT 4.2.5 for Windows will continue to be available for download for a few months during the transition to the new MARPLOT 5 series.

Getting Help

You can report software bugs or obtain additional assistance by emailing the RMP Reporting Center (, or by calling the CAMEO help desk at (703) 227-7650 on weekdays from 8 AM to 4:30 PM, Eastern Time.

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