Site Parcel Essentials – Part 1

Tags grading, site, parcel, site parcel, subdivision

It’s probably been too long since I really posted about AutoCAD Civil 3D Parcels. Looking back I don’t think I ever really posted on the Civil 3D Site Parcel collector and it’s mechanics in much detail here.  I decided it was time to do a write up. This will take a number of posts. There is a lot going on the Parcels.

Gimmie Gimmie That Funky Stuff

A Bunch of Parcels

I haven’t talked Parcels a lot is probably because like many of you, I really wish Autodesk would do some fix up to this very useful and much needed Feature. All too often these days, we are still stuck with employing dumb CAD primitive objects to construct and often reconstruct too much Parcel geometry.
Parcels got some funky stuff as we’ll discover along the way.

The Parcel Posts - a study guide to Read and Test in AutoCAD Civil 3D
Site Parcel Essentials – Part 1 | It’s Not Yo’ Daddy’s Parcel – Part 2 | To Edit Parcels is to Create? – Part 3 | Parcels Have Priorities - Part 4 | A Strange Universe of Parcel Inverses and Mapchecks – Part 5 | Dances with Parcels – Part 6 | Pack Dances with Parcels – Part 7 | Cycle Manipulations of Segments – Part 8 | Select Manipulations of Segments – Part 9 | Visual Manipulations and Many Segments – Part 10

How Do We Think About Parcels?

I don’t believe we can talk about parcels without thinking about how our survey, civil engineering, GIS disciplines, etc. think about and actually perceive parcels differently.
Oh and we do think differently and for good reasons.

For human beings is all about perception, expectation, and the tools we employ in the specifics of the pursuit of our trade. That last bit regarding us as tool users is often a lot more powerful or impactful on our thought processes and daily behavior than we intuitively believe.

I Know People Think Differently
Do I Behave as if They Do?

We know the statement above to be true. We just don’t think and operate on the knowledge and belief as often as we should - Also true.

All too often we use the same “parcel” word and mean something different. For the sake of brevity I’ll keep this simple and ask you to keep foremost in your mind that tool using idea.
Is the Civil 3D Parcel engine an ax or a chainsaw?

Survey

If you’re a Surveyor the “parcel” is an arrangement of point data with some linear features defined by point data in between. If you ask the surveyor for the parcel data, he’ll toss you the point data and a traverse report. As CAD stuff this will be points maybe with lines and curves, but only if he has to.

Civil Engineer

The parcel is almost always seen as an arrangement of quasi-connected linear features, Points are seen as information on the linear features. A parcel has some other (usually annotative) information loosely attached to it. If you ask the engineer for the parcel data, he hand you linear features. As CAD stuff this will be lines, curves, and/or polylines.

GIS

The parcel is array of records in one or even multiple databases. It is normally part of a topology that relates it placement in space with potentially many other objects in potentially other different topologies. If you ask the GIS professional for a parcel, he’ll give you a report of the parcel record(s) and/or all or part of the core parcel topology. As CAD stuff this will be closed polygons with DATA attached.

The Assessor

The parcel enters and exists in the world of Property Rights, the Rule of Law, and legal, quasi-legal, and illegal Contracts. Recorded or not - In here the parcel is all about Value which is always a matter of human debate. Maybe this is so we have an ongoing reason to support lawyers, accountants, realtors, title companies, and banks. Er? Did I mention government agencies?
Parcel “resolution” keeps many of us working as well. I’m not complaining.
Suffice it to say the parcel in here exists in many separate and often blurred realities.

I love to use the example of the California statute (a legal decision) that says if a tree is within 3 feet of a property line and the tree reaches (as I recall) 24” in diameter the tree becomes an “historic” tree. The tree becomes the property and responsibility of both adjoining landholders. The property line is now deemed to pass through the center of said tree. However, this may not alter the recorded parcel document in any way as the tree may die at some time in the future. At that point the property line then reverts back to its original recorded position. Killing the tree is of course banned as the tree is now deemed to be “historic”. The statute does not however apply to trees in any public right of ways or easement as that was deemed to be an undue financial maintenance burden on public agencies. Fascinating stuff and now probably my understanding is completely out of date.
We could go on and on...
Nuff said.

Parcels in AutoCAD Civil 3D

What about parcels in Civil 3D?

Civil 3D Parcels obviously seem to favor the civil engineer’s perspective with a bit of the other disciplines tools and data viewpoints thrown in.

However, how the quality control work gets done employs survey analysis tools and Civil 3D actually employs a GIS like topology engine to accomplish a good bit of the "design" work. Huh?

No wonder we’re all a bit bemused about Civil 3D parcels.

Next time – It’s all about the Parcel Design Topology.