The Art of the Span: Parcel Labeling

This post has been a long time coming, and in fact, it is going to have to be a series of posts and maybe even a Made for TV Movie.

I have been working on the manuscript that I affectionately call “1001 Ways to Blow a Spanning Label” for a few months now, and though I do not have all of the answers, I figured that I could share a few things tonight that would help you get going, and I can expand on them over the course of the next few weeks (or months or years)

Click more to explore the joys of spanning labels….

Before I begin, I would like to say a hearty thank you to Chris Putnam, Glen Albert, Nick Zeeben and all of the other guys “on the inside” at Autodesk who have helped me get inside the head of the spanning label. 

The team at Meridian and I have finished up a few really nice final record plats for medium to large subdivisions and made a “platting template” with a bunch of spanning and non-spanning label styles that meet our county spec, as well as an order of operations for what to label first, when to use multiple, etc.  

We couldn’t have done it without their help. 

And on that note, I’d like to thank Shelly, Todd and Kathy at Meridian for putting up with me slamming my head against their desks, smudging their screens with my jelly doughnut fingers and making me go to the gym with them over lunch to work off the spanning label stress (and the jelly doughnuts).

Tonight, we will hit three basic things that MUST be considered to get a spanning label to work.
** It goes without saying that you must have good site topology.  Visit the following links if you are unfamiliar with site and parcel behavior:
  1. Parcel Rules Explained
  2. Site Geometry Basics
  3. Site Topology (from Wicked Cool Stuff)
1) Make sure your style is set to span

The default spanning label in the out-of-the-box NCS template is actually set NOT to span.  So your initial attempts to get spanning labels to work probably were doomed to fail from day one since the default template had a problem.  So before you do ANYTHING, make your style correctly. 

 I always set EVERY component in a spanning label to “span the outside segment” such as: the table tag, bearing, the distance, radius, delta, and the direction arrow.

The most critical thing is usually the distance, but having the others set to span doesn’t hurt me.  The direction arrow being set to span is actually pretty handy because you can tack label components on to them and if everything goes smoothly, they will show up at either end of the long segment.

2) Spanning Labels will NOT cross natural vertices, but they will cross “split created” vertices UNLESS the parcel segments make an “X” shape

Natural Vertex: A “grip” vertex.  If you draw a polyline with a couple of segments, then select the polyline, those blue grips are at natural vertices.  When you convert that polyline into a parcel segment, those natural vertices will remain.

Split Created Vertex: Created automatically when a parcel segment touches or crosses another parcel segment

This means that if you want certain segments to be labeled, you must make sure that you create geometry without natural vertices.  You can draw them as lines, arcs, polylines, etc. then define as parcels by object, or use the parcel creation tools.  Either way, be conscious of where you are sticking those natural vertices.

Also note that span labels will span split created vertices for “T” type intersections, but they will not span “X” type intersections.

If you already have your geometry defined and you run into a problem like this one:

You can fix it a few ways:

1. Explode the whole site and start over (ha)

2. Use the parcel segment erasing tools and erase the segment, then draw it again using either a carefully drawn polyline->define from objects, or using the parcel line creation tool. (my method of choice)

3. Use the delete PI tool from the parcel segment editing toolbar (doesn’t always return results that do what I want, so I tend to only use this in really straightforward cases)

3) The side of the segment that your label is on MATTERS; The distance your label is from the segment MATTERS

This one is a little weird, and you would think it shouldn’t matter, but it does. 

The spanning label must be composed on the side of the segment that does not contain the segments that created the split created vertices.

That is a mouthful, so here are some pictures:

This doesn’t tend to sting me as much for line segments because I usually want the spanning distance reading on the outside.  Where it comes into play most of the time is in curve labels, where you might have your length stacked on top of radius in order to save space or some variation like that.

If I flip the label (OR if I had composed my label to stack length over radius), the length no longer spans.  Keep in mind that this is a properly composed label from a spanning perspective- but the SIDE MATTERS.

The other thing I discovered is that if your spanning label is on a curve, if the curve label is not composed to offset far enough from the curve segment it won’t “see” that it is on the opposite side of the segment from the split created vertices. 

This is a subject we can spend more time on in the future.

The fix for this is to go into your style and play around with the offset until the label returns the correct value.  Test this on your tightest radius and be diligent about checking it when you go through your site plan checks.

  1. Parcel Direction
  2. Reversing Labels
  3. Flipping Labels
  4. The Direction Arrow
  5. Our old friend Topology
  6. Much More

But take heart  Once you get your head around the spanning label and other parcel labels, site plans move very quickly.

Something else that has been a benefit is that because parcels like to be closed, and all of their other “rules”, we have found some bad geometry in site plans and been able to fix it right from the get go.


  1. dgordon says:

    Someone mentioned on the autodesk discussion groups that you had posted a way to change the bearing format of 0 degrees 00′ 00″ to 00 degrees 00′ 00″. If this is true could you share it with me?

  2. that isn’t true… the leading zero is one hack i have yet to discover, sorry!