|
Dragon refers to any of several remote sensing image processing software packages. This software provides capabilities for displaying, analyzing, and interpreting digital images from earth satellites and raster data files that represent spatially distributed data. All the Dragon packages derive from code created by Goldin-Rudahl Systems, Incorporated, and focus on geography education: * ''OpenDragon'' is free to educational users. It was intended to be free worldwide, as well as open source (hence the name) but due to funding problems, is currently available only in Southeast Asia. * ''Dragon Academic'' is functionally identical to OpenDragon. * ''Dragon Professional'' is expanded to handle full-scene data sets from sensors such as Landsat TM, SPOT, and Aster. ==History== The initial version of Dragon was released in 1987 and ran on the MS-DOS operating system. Dragon was the first commercial remote sensing software package designed to use only the native capabilities of off-the-shelf personal computers. At the time Dragon was developed, other PC remote sensing products such as Erdas required expensive special purpose graphics devices. Dragon was intended to be used for education in geography, geology, forestry and other disciplines that use spatial information; thus it was very important to minimize the costs of required hardware. The first version of Dragon ran on a basic IBM-PC with two floppy disks and a four-color or gray-level graphics display. Alternatively, it could use any of several models of Japanese PC. The MS-DOS phase of Dragon development focused on trying to squeeze functionality into very limited disk and memory space, and to get full-color image display using rapidly changing graphics hardware with no standardized drivers. The VESA display standard was a turning point in making full-color display functionality available in MS-DOS. This VESA/SVGA/MS-DOS version of Dragon can still be adapted for embedded systems use. The move to Microsoft Windows 95/98 was painful because these operating systems did not provide true multitasking. Unfortunately this phase coincided with the publication of the well-known Gibson and Powers textbook (Gibson,2000) which included a copy of the Windows 95 Dragon. With the advent of Windows NT and successors (Windows 2000, XP, Vista, etc.), it became possible to create a Windows version of Dragon that allowed simultaneous display of and interaction with multiple images. In 2004, funding became available from Thailand to create a free educational version of the software which became known as OpenDragon. This project lasted for three years. The software is still available at no cost in Thailand, Laos, Cambodia and Vietnam (although it has only been translated into Thai). After funding for OpenDragon was discontinued, Dragon Professional was developed to reach beyond the customary educational users. New personal computer capabilities, which by then extended to gigabytes of memory and hundreds of gigabytes of disk storage, all at low cost, made it possible to store and process the very large data sets produced by twenty-first-century high-resolution satellites. Dragon Professional required major changes in the user interaction model, which previously had assumed a 1-to-1 relationship between the image on the screen and the sensor data. At the same time, image processing operations such as selection of ground control points require access to individual data elements (pixels) selected from the more than 30 million available in a typical full-scene image. Thus, the appearance and behavior of Dragon Professional are quite different from OpenDragon/Dragon Academic. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dragon (remote sensing)」の詳細全文を読む スポンサード リンク
|