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OpenDragon Functional Description

OpenDragon provides a robust suite of image processing operations, via an intuitive, responsive, multi-window graphical user interface.

Software functionality includes full-color display, annotation, enhancement, measurement, supervised and unsupervised classification, georeferencing, on-screen vector capture, and a broad range of other capabilities to support image processing education and research. OpenDragon can access image and data files created by earlier releases of commercial Dragon, can run scripts created for other versions, and is backward compatible in its organization and navigation.

OpenDragon uses an innovative client-server architecture and is based on platform-independent industry standards including Java, XML and HTML. The OpenDragon architecture supports new levels of user extensibility and will eventually allow the software to execute on Windows, Linux, Mac OS/X, and Solaris and other Unix variants.

Platform Requirements

OpenDragon requires a computer running Windows XP, Windows 7 or higher. We recommend at least 256 MBytes of RAM and at least 200 MBytes of available hard disk space. A full-color graphics board and a pointing device (mouse, trackball, etc.) are also required.

OpenDragon Capabilities


  • Examine data from satellites, aerial photography and Geographic Informations Systems in full color, in pseudo-color, or in gray. Compare images across multiple windows. Zoom images to view them in greater detail, or scroll to examine hidden areas. Annotate images with internationalized (Unicode) text and color-patch legends. Create color schemes for classification displays or density-slicing.


  • Transform digital images to highlight information or to suppress noise. Apply linear or non-linear contrast adjustment. Compute standard arithmetic combinations (sum, difference, and ratio). Perform filtering, vegetation assessment and classification post-processing. Apply a mask to restrict processing to specific study areas or regions of interest. Transform images bands to make them more independent.


  • Assign each point in a digital image to the appropriate category of ground cover, land use or other surface characteristics using maximum likelihood, minimum distance to mean, or boxcar supervised classification. Alternatively, assign image points to classes based on the structure inherent in the image data ("unsupervised classification"). Select samples to define each supervised classification category, directly or by reference to GIS or other ancillary raster data set. Display and edit sample histograms and statistics. Recode classified or other images based on simple or complex rules. Evaluate classification accuracy by creating confusion matrices.

Register Images

  • Identify and evaluate control points. Rectify or geometrically correct images, registering them to maps, other images, or standard coordinate systems.

Measure and Analyze

  • Interactively display data values and radiometric profiles. Measure lengths, perimeters and areas. Display histograms, scatterplots, and image statistics. Create and analyze polygon overlays. Import, export, or rasterize vector data files. Extract irregular subareas to exclude irrelevant data or create a mask.

Build GIS Models

  • Calculate slope and aspect from elevation data. Define fixed width buffers around features of interest. Combine image data and raster GIS layers according to logical rules to produce new information and support decision making.

Communicate across Applications

  • Load a subset of an image file, or save processing results in a new image file. Exchange OpenDragon results with other image processing and GIS packages. Capture annotated images as graphics files for use with desktop publishing packages. Save reports as HTML for importing into web or other documents.

Teach and Learn

  • Access the full user manual interactively from within OpenDragon to obtain descriptions of and details on the current OpenDragon operation. Create scripts to automate common functions and provide student examples. Provide common datasets for teaching via a networked file server.

OpenDragon Speaks Your Language

  • OpenDragon is fully internationalized, and supports multiple languages including English, Thai, Chinese (Traditional), Turkish, Indonesian, Spanish, French, Portuguese, Russian and Czech. In addition, a Polish version is under development.