logical circuit provisioning, Snapping

A CDOT Snapping Case Study: It’s a Snap

April 9, 2016 — Brian Higgins

SSP is excited to have Brandon Carrick as a cowritter of this publication.  His brief biography is included below.


With Colorado Department of Transportation’s (CDOT) over 1000 miles of conduit and fiber optic cables, the GIS staff of four is consistently busy not only digitizing newly installed features, but also maintaining the existing system as maintenance/replacement is conducted.  This post will outline CDOT’s establishment of snapping environmental variables to assist staff productivity and accuracy.

An important job of the GIS Administrator is to establish a default editing environment.  A solid editing environment makes the users much more efficient and accurate.  SSP has previously written about several environmental aspects to include:

What has not previously been written in detail by SSP is establishment of the snapping environment.  When digitizing any feature which is part of a geometric network, the coincident spatial location with other features of the same geometric network is of major importance.   Quite frankly, if a feature (i.e. Splice Case) is digitized and doesn’t snap to the fiber optic cable, the Fiber Manager™ tools will not function properly.

Snapping Configuration

 

Within ArcCatalog and ArcFM™, an administrator has the ability to easily establish default snapping.  Two items must be determined:

  • Determine the desired feature class(es) to snap.
  • Which of the three options (Figure 1) of each feature class to snap.
Figure 1. Feature Snapping Options

As an example, a linear fiber optic cable has three options for snapping:  Vertex, Edge, and End (Figure 1).  A splice case point feature class has the Vertex option.

To establish default snapping for the splice case, conduct the following procedures within ArcCatalog:

  • Right-click on the SplicePoint feature class, and choose the ArcFM Snapping Manager option (Figure 2).  There is also a tool to directly access this from the ArcFM Solution toolbar.
Figure 2. Accessing ArcFM Snapping Manager
  • Within the ArcFM Snapping Manager (Figure 3), we can add the FiberOpticCable (if not added previously) by selecting it and clicking the down arrow.
Figure 3. ArcFM Snapping Manager
  • The options of Edge and End are chosen and the changes are applied
The default snapping for a fiber optic cable is a bit different in that it snaps to multiple feature classes (Figure 4).
Figure 4. ArcFM Snapping Manager with Multiple Feature Classes
  • The vertex option is chosen for the multiple point feature classes.
  • Currently, the snapping order is established that splice cases have the highest priority and devices have the next priority etc.  To change the order, highlight the desired feature class, and click the arrows highlighted at right.
It should be noted that if not already done, the option to create features using templates in the ArcMap Advanced Settings Utility should be turned off.  When enacted, we have seen this interfere with ArcFM default snapping.  The ArcMap Advanced Settings Utility is located in c:\Program Files (x86)\ArcGIS\Desktop10.2\Utilities\AdvancedArcMapSettings.exe (Figure 5).
Figure 5. Advanced ArcMap Settings

Digitizing Procedure

 

Digitizing fiber features (or any other features) with the ArcFM™ methodology requires three steps as follows:

  • Start an editing session.
  • Enable the Features Tab of the Table of Contents.  
  • Enable the Targets Tab of the ArcFM™ Attribute Editor

CDOT has a rule that all fiber features are to be digitized from ArcFM Favorites (Top of the Features Tab).  This way….all the pre-established related objects, properties, and default snapping are already present.

Snapping Override

 

As a general rule, point features (collected via GPS) are digitized prior to the linear fiber optic cables.  When digitizing the subsequent cables, there are often times an individual must override default snapping.  Brandon of CDOT has previously compared default snapping to “being caught in the jaws of an alligator”.  When features are close together and default snapping is set to multiple features classes, one will sometimes get the behavior of snapping to undesired features.

There is an easy solution (“King of all Kings”) to this “Evil” behavior.  Prior to digitizing/placing the feature where undesired snapping is occurring, hold the Space Bar down.  While the cursor is over the desired location, release the Space Bar.

Snapping Environment Window

 

Another solution to overriding ArcFM™ default snapping is the Esri Snapping Environment Window (Figure 6).  This window can be accessed via clicking on the Editor button on the Editor toolbar, selecting Snapping, and then clicking Snapping Window.  One then has the ability to check and uncheck certain features for desired snapping to the active digitized feature.  If using multiple monitors, this window may be “stored” on the second monitor for prompt, easy access.

Figure 6. Snapping Environment Window

In conclusion, it is our hope that this blog post provided a brief summary of the establishment of the snapping environment and a means of override.  Your comments are always welcome and encouraged.


Brandon

About the Cowriter……

 

Brandon Carrick is a GIS Specialist at Felsburg Holt & Ullivig.  He is currently assisting CDOT in the GIS/Environmental group.  He graduated from the University of Colorado, Colorado Springs with a B.S. in Geography and Environmental Studies with a GIS Certification.
 

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