# Smooth the map

Shapefiles with polygons typically contain too many data points and too much detail for statistical map visualizations. The excess details can be distracting and negatively impact performance. You can reduce the level of detail and generalize the map with smoothing. The map will look crisper and render more quickly as a result. This option is not available for point and polyline maps.

**Max. angle.** The maximum angle, which must be a value between
1 and 20, specifies the tolerance for smoothing sets of points that
are almost linear. A larger value allows more tolerance for the linear
smoothing and will subsequently drop more points, resulting in a more
generalized map. To apply linear smoothing, the Map Conversion Utility
checks the inner angle formed by every set of three points in the
map. If 180 minus the angle is less than the specified value, the
Map Conversion Utility will drop the middle point. In other words,
the Map Conversion Utility is checking whether the line formed by
the three points is almost straight. If it is, the Map Conversion
Utility treats the line as a straight line between the endpoints and
drops the middle point.

**Percent to keep.** The percentage to keep, which must be
a value between 90 and 100, determines the amount of land area to
keep when the map is smoothed. This option affects only those features
that have multiple polygons, as would be the case if a feature included
islands. If the total area of a feature minus a polygon is greater
than the specified percentage of the original area, the Map Conversion
Utility will drop the polygon from the map. The Map Conversion Utility
will never remove all polygons for the feature. That is, there will
always be at least one polygon for the feature, regardless of the
amount of smoothing applied.

After you choose a maximum angle and percentage to keep, click Apply. The preview will update with the smoothing changes. If you need to smooth the map again, repeat until you obtain the level of smoothness you want. Note that there is a limit to the smoothing. If you repeatedly smooth, you will reach a point when no additional smoothing can be applied to the map.