Transform - Distance Network

The Distance Network transform operator creates a network link between all points within the given distance.

 

images\sc_distance_network_01.gif

 

In the illustration above we've created a grid of points using the View - Grid tool. The points are 48 meters apart horizontally and vertically.

 

images\sc_distance_network_02.gif

 

Setting up the transform toolbar as seen above with a distance of 50 will result in the following network.

 

images\sc_distance_network_03.gif

 

Links have been drawn between neighbors in a vertical and horizontal pattern. The diagonals have not been drawn because the hypotenuse between points is greater than 50 meters.

 

If we delete the selected lines added by the transform and run the Distance Network operator one more time with a value of 70 we get the following result:

 

images\sc_distance_network_04.gif

 

In this case links have been drawn on the hypotenuse diagonals as well because each point is 69 meters away from the diagonal neighbor (as is easily seen with the Tracker tool).

 

Note that in both of the above cases, the Distance Network operator created two links between each point: one in each direction. The extra links can be deleted by selecting all links and then running the Normalize Topology transform operator. This will delete duplicate coincident links.

 

Units of Measurement

 

Units used for the distance value in the source / argument box are taken from the projection of the drawing. If the drawing is in Latitude / Longitude projection the units will be degrees. If the drawing is projected, the units will be in meters or feet. It is therefore strongly recommended that the drawing be projected first so that meters or other linear measure can be used instead of attempting to use degrees as a measurement unit.

 

To see which units are defined for the drawing's projection, click on the Tracker tool and make some measurements. Whatever units are used to show the result of the tracker tool are the units currently in force.

 

If the drawing uses degrees and meter-based creation of buffer zones are desired, first re-project the drawing into any convenient meter-based projection (such as Orthographic) so that meters will be used as the units of measure.

 

When this transform operator is used with a drawing layer within a map the units used by the drawing will be used. If the map component's projection is degree based while the native projection for the drawing is meter based (as, for example, with the Orthographic projection) or vice versa, then the transform operator will use whatever units are used by the drawing's projection.