Map Data
- Raster data
- Vector data
- Photos
Raster Data
A raster data type is, in essence, any type of digital image represented in grids. Anyone who is familiar with digital photography will recognize the pixel as the smallest individual unit of an image. A combination of these pixels creates an image, distinct from the commonly used scalable vector graphics which are the basis of the vector model.
Raster data type consists of rows and columns of cells, with each cell storing a single value. Raster data can be images (raster images) with each pixel (or cell) containing a color value. Additional values recorded for each cell may be a discrete value, such as land use, a continuous value, such as topography, or a not-computed-value if no data is available.
Vector Data
- Lines
- One-dimensional lines or polylines are used for linear features such as rivers, roads, railroads, trails, and topographic lines.
- Polygons
- Two-dimensional polygons are used for geographical features that cover a particular area of the earth's surface. Such features may include lakes, park boundaries, buildings, city boundaries, or land uses. Polygons convey the most amount of information on the file types. Polygon features can measure perimeter and area.
Photos
Photos, for example, aerial pictures, can be used as background images or can be converted into vector data.