Displaying Vector Data

Producer Field Guide

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Producer Field Guide
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Vector data are displayed in Viewers, as are other data types in ERDAS IMAGINE. You can display a single vector layer, overlay several layers in one Viewer, or display a vector layer over a raster layer or layers.

In layers that contain more than one feature (a combination of points, lines, and polygons), you can select which features to display. For example, if you are studying parcels, you may want to display only the polygons in a layer that also contains street centerlines (lines).

Color Schemes

Vector data are usually assigned class values in the same manner as the pixels in a thematic raster file. These class values correspond to different colors on the display screen. As with a pseudo color image, you can assign a color scheme for displaying the vector classes.

See Image Display for a thorough discussion of how images are displayed.

Symbolization

Vector layers can be displayed with symbolization, meaning that the attributes can be used to determine how points, lines, and polygons are rendered. Points, lines, polygons, and nodes are symbolized using styles and symbols similar to annotation. For example, if a point layer represents cities and towns, the appropriate symbol could be used at each point based on the population of that area.

Points

Point symbolization options include symbol, size, and color. The symbols available are the same symbols available for annotation.

Lines

Lines can be symbolized with varying line patterns, composition, width, and color. The line styles available are the same as those available for annotation.

Polygons

Polygons can be symbolized as lines or as filled polygons. Polygons symbolized as lines can have varying line styles (see "Lines", above). For filled polygons, either a solid fill color or a repeated symbol can be selected. When symbols are used, you select the symbol to use, the symbol size, symbol color, background color, and the x- and y-separation between symbols. The figure below illustrates a pattern fill. The vector layer reflects the symbolization that is defined in the Symbology dialog.

Symbolization Example

symbology_zone88