Best Practices in Land Surveying: Creating Superior Land Description Plats

This entry is part 8 of 8 in the series June 2014

Part 2

By Landon Blake

ArticleIn the last Best Practices article (March 2014), we considered land description plats in general; here we address dealing with the challenge of covering a large or complex parcel on a small sheet size and establishing a visual hierarchy using only black and white ink.

Let’s consider these suggestions as they would apply to the sample land description for an agricultural land conservation easement in Figure 1.

Figure 2 is a simple map of the conservation easement parcel.

Overcoming the Challenge of Small Sheet Size

Most plats are recorded on 8.5- by 11-inch sheets, and most county recorders require at least a 1-inch margin. This leaves us 6.5 by 9 inches of printable space on our plat with which we can show the subject parcel. For a subject parcel that is large or has complex geometry, it can be a challenge to fit all of the necessary labels and other data on a single sheet. Our agricultural conservation easement (ACE) is a good example. We’d probably have a hard time creating an uncluttered land description plat for this parcel on a single sheet.

As mentioned in the last article, we can overcome this challenge by using multiple sheets to show our plat. Consider our example ACE parcel—how would we use multiple sheets to show this parcel? I’d probably do the following on my plat:

  1. Rotate the viewport on each plat sheet 90 degrees (use a landscape view).
  2. Cover the subject parcel with two  main sheets. The first would show the north half of the parcel and the second would show the south half (Figure 3).

I don’t know that I would need a detail on this particular land description plat, although that is another tool to deal with the small sheet size. If there were more complexity in the configuration of the farm buildings doughnut hole excluded from our ACE parcel, I would consider using a separate sheet for a detail of that area.

Any time I use a multi-sheet layout for a plat or another type of map, I include a sheet index. This provides an overall view of the subject parcel and shows the footprints of the subsequent sheets.

You will also note that my example ACE parcel description includes some ties to geodetic control in its commencement courses. That means we will either have to use line break/line extension symbols or include a separate sheet to show the commencement calls.

In this case I would probably eliminate an extra sheet by showing my commencement calls on the sheet index if this could be done without much clutter.

The example ACE parcel doesn’t contain any sequences of short courses in its boundary, and it lacks curves. As a result, I don’t think any line or curve label tables will be needed for this plat.

Based on this analysis, it looks like the plat I would create for the example ACE parcel would contain three sheets:

  1. Sheet Index/Commencement Calls
  2. Parcel View #1 (north half of subject parcel)
  3. Parcel View #3 (south half of subject parcel)

I would need to make sure that match lines and clearly identified sheet numbers were included on all pages of the plat.

Establishing Visual Hierarchy

The second challenge I mentioned in the last article is establishing a visual hierarchy in land description plats. Visual hierarchy is an important tool on any map because it helps the viewer determine what information is the most critical and it helps to organize similar elements of the map into categories or groups. On land description plats we can use visual hierarchy to help the viewer categorize the points (with symbols), lines (with linetypes and lineweights), and areas (with fills or hatch patterns).

For the sake of simplicity, let’s consider just how we could establish a visual hierarchy for lines on the plat for the example ACE parcel. Remember that in almost all cases we can’t use color to distinguish different types of lines on a plat; we’ve got to use line weight and line pattern (or line type).

The first step is to identify the different types of lines on the plat that may be important to the plat viewer. I find it helps to think a bit like a GIS professional or geographer at this point. Separate your lines into different feature types, and then rank this in level of importance to the viewer.

Here is the list of line features I came up with based on the written description of the example ACE parcel:

1)  subject parcel boundary (conservation easement),
2)  parent parcel boundary,
3)  commencement tie lines,
4)  river lowland boundaries,
5)  river banks,
6)  adjoining parcel boundaries, and
7)  adjoining road right-of-way boundaries.

You might also want to separate that first category into portions of the easement boundary that are defined as a meander and portions that are not. (You might use a dashed line of the same weight for the meander portions of the subject parcel boundary.)

It is easy to over-do things when establishing visual hierarchy. Often, less is more. I probably wouldn’t use seven line types on my plat; I’d use the same line type and line weight for the boundaries of the river lowlands and the river banks. I’d also use the same line type for the adjoining parcel boundaries and the adjoining road right-of-way boundaries (Figure 4).

Continue to follow Landon Blake’s writings on best practices in surveying, as well as on a variety of topics including CAD and open-source geospatial software, in our new publication xyHt, both in print and online.

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