Image data is a form of raster data in which each cell in the image has a row and column number. Each cell, or pixel, contains color, saturation, and hue values. Raster data is highly dependent on the resolution of its grid, or number of pixels per unit area. The size of the cells in the grid is fixed, so as you zoom in on raster data you will eventually see the individual cells. Scale Scale describes the relationship between a map and the portion of the earth the map represents.
Scale is the reduction needed to display a representation of the Earth's surface on a map.
Spatial data Spatial data is the geographic reference information about map features. Themes A theme is a set of geographic features of the same type that can be displayed in a map view. An image data source such as a satellite photo. A table containing XY coordinates, or street addresses that can be geocoded. Note that a theme points to the geographic data it represents.