Читать книгу Imagery and GIS - Kass Green - Страница 20

The three primary uses of imagery in a GIS are

1 1.as a base image to aid the visualization of map information, as shown in figure 2.11

2 2.as an attribute of a feature. For example, an image of vegetation taken from the ground may serve as an attribute of a vegetation survey point displayed on a map, as shown in figure 2.12

3 3.as a data source from which information is extracted through the process of image classification. For example, imagery may be interpreted by image analysis to determine the current state of situations for disaster response, environmental monitoring, or military planning. Imagery can also be transformed into informational map classes through manual interpretation or semi-automated classification.

The focus of much of this book is on the third use—image classification, which is the process of utilizing imagery in a GIS to produce maps.

Figure 2.11. Imagery as a base image. This figure shows airborne infrared imagery as a base image with parcel boundaries (in yellow) and field data points (in green). (esriurl.com/IG211). Source: Sonoma County Agriculture Preservation and Open Space District

Figure 2.12. A field-captured image as an attribute of the survey point geodatabase. Source: Sonoma County Agriculture Preservation and Open Space District