Coordinate system zones and neatline clipping

Coordinate system zones

There are cases when the area of interest of a grid intersects more than one coordinate system zone, for example, Universal Transverse Mercator (UTM) or State Plane. In such scenarios, the merging of the grid lines and their ticks is required. This is sometimes referred to as converging zones or zippers. For small-scale maps, this effect may be repeated several times across the extent of the area of interest. The zones will start and stop at the zone boundaries.

To create the zones, the Grids and Graticules Designer has the Coordinate System Zones settings as a grid property. This enables you to load polygon feature classes or shapefiles with defined coordinate systems that will be embedded in or saved to the grid template. The coordinate system zone feature class is used to define the zone boundaries or extent. The feature class must have a short integer field that identifies each zone and a text field that stores the spatial reference information in coordinate system or projection file (.prj) text format. A selection rule parameter determines which zone to choose for grid component creation when the area of interest intersects more than one zone or extent. For example, the primary coordinate system of a grid, for an area of interest that intersects UTM zone 10 and 11, is calculated from the Coordinate System Zones feature class and is based on a selection rule of largest area.

Neatline clipping

Segments can be clipped at coordinate system zone boundaries using the Clipping setting in neatline. This gives you the flexibility of clipping neatlines and all subcomponents, like segments, gridlines, ticks, and points, to an extent defined in the Coordinate System Zones feature class or shapefile. Clipping is based on Ordinal Rank, a priority ranking. The components must have the coordinate system zone set to indicate which zone they are created over. In the above example, neatlines falling in each UTM zone 10 and 11 can be set to clip to the corresponding UTM zone.


9/17/2010