When working with a very large shapefile, zooming in closely on a set of features improves the redraw speed only slightly, or doesn't seem to improve at all.
Redraw speed can be improved by creating a spatial index on the themes in the view.
· A spatial index is automatically created, if one doesn't already exist, when you do a spatial join or a theme-on-theme selection.
· You can create a spatial index by using the Avenue request 'BuildIndex' on any coverage feature source.
· You can create a spatial index in ArcInfo with the INDEX command. ArcView will use that index.
You can determine whether a feature data source contains an index by using the Avenue request 'HasIndex'.
· You can also create a spatial index from the ArcView interface:
1. Open the theme's table.
2. Make the Shape field active.
3. Select Create Index from the Field menu.
If the menu only shows a Remove Index option, a spatial index already exists for that theme/coverage.
With a spatial index present, once you zoom in to a large scale portion of the view, the redraw only occurs on the features actually in the View window itself.
Creating a spatial index writes two files (*.sbn and *.sbx) to the directory containing the source shapefile.