Strategy question: What is the best way to manage overflow annotation on street maps?

By Charlie Frye, Esri Chief Cartographer

We got one of those perennial ‘tough nut’ questions on Ask a Cartographer today. The question has to do with using annotation versus on the fly labeling with Maplex and what are often called overflow labels, which I have also heard called “key lists”. While we are able to recommend tips and tools for specific circumstances or implementations, the person asking was more interested in what is the best strategy and why. So here’s their question:

“We produce a 1″=1000′ City map book from our GIS, similar to the Thomas Bros. street guides. The street names are annotation which has been carefully placed to best fit and while we’ve looked at Maplex we feel that our annotation is currently the best solution.

An issue has recently been raised at to how to best handle the names which do not fit on the streets. What we’ve done up until now is to place a sequential number on the street(s) and then have a table placed nearby with the number and the street name. Each individual tables usually starts with the number “1″ and sequences up.

This works fairly well in the map book format, where the page boundaries are predictable and the tables are placed with this in mind. However, it doesn’t work so well with custom map projects, where the streets may be separated from the tables by the map boundary.

One proposal to make the maps easier to read has been that all the overflow street name should have an unique sequence number, city wide. This would make it easier to determine which table goes with which streets, but on the other hand I think we have around 750 street names in the tables, so the numbers would be large. This then becomes a larger issue when you want to add a new street to an
existing table – do you have a number in the table which isn’t in sequence, or do you re-sequence all the tables citywide.

Thomas Bros. has their overflow tables always starting with “1″, but they have a symbol and letter (“A” in a triangle for example) which is placed by the tables and also by the streets to indicate which text block goes with which group of streets.

We see pluses and minuses with all three methods for labeling the overflows. We were wondering what others are doing and if there are other options out there that we haven’t thought of, and also if there is a “best practice” that we should be following.

Thanks in advance for any ideas or suggestions.”

Please respond in the comments with your ideas and suggestions.

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4 Comments

  1. egeddes says:

    Great question. I could be wrong, but I’m guessing that if the areas you are mapping are like the ones I work with, the streets too short to contain a name, tend to be less significant streets in the minds of the folks who will eventually use the map.

    As such, I’m not sure the user would benefit from having each of these assigned a unique number. Moreover, I would argue each table should not contain more than 9 references (1-9) so as to take advantage of the fact that a single number will be less likely to be confused sub-consciously with a street name. And, the user may wonder if there is some deeper significance to the numbering system which, is almost certainly arbitrary (or alphabetical — close enough).

    Then again, I’m not entirely sure avoiding overflows in favor of lookup tables is the answer. In the example image shown in the post, the names shown in the table, if oriented parallel to the corresponding street, would not introduce much “disruption” to the user. Less disruption, in my opinion, than a table abstraction.

    As an aside, one of the best resources I’ve found for addressing issues specific to the area I’m working in/on is to assemble a reference book. I go to a local bookstore, and purchase one street map of the area from each publisher, and photocopy portions into a reference. It makes a big difference when solving a problem to see the decisions others have made regarding the same exact problem.

    Just a thought — let us know what you decide. Cheers.

  2. jneild says:

    Great question!

    I was reading the post and noted the discussion centered around what appears to be manually managed annotation versus automated labeling using Maplex.

    You made some comments in the post about different tips or tools for doing this type of process, but no reference to examples of those tips/tools. Could you post some of the tips/tools that could be used to achieve a similar result to the image?

  3. tesladaman says:

    Knowing that your map is at just small enough a scale to require a key list is the first trick. I use the Draw Unplaced Labels mode that is on the Labeling toolbar to get a rough idea. If I see clumps of red labels, there’s probably a case for key lists (note that in most cases my street data have been desolved by name and type to ensure extra labels are not being generated because the streets are broken into multiple features).

    Next, to pre-load the workflow, you could either draw graphic boxes around those areas–so you know where to visit once you have created annotation (or rely on turning on the unplaced annoation in the annotation layer properties) and pan from area to area, moving the labels and editing them to have the number, and then creating new annotation for the numbers to place on the streets.

    The problem with that approach comes when you have a fairly large area to map–maybe as a mapbook or map series. Then it would be nice to know where all the congested areas are located. One idea there is to convert the streets (again dissolved by name and type) to points and then use the cluster analysis tools (spatial statistics toolbox) to find clusters. Find the level of clustering that corresponds with the clumps of unplaced labels that require key lists, i.e., finding the meaningful cluster tolerance. Then you can summarize the cluster data (with high enough tolerances) by cluster number and get a checklist to follow.

    At one point, we prototyped a keylist tool in ArcObjects which would take the selected annotation features, sort, number and replace the labels with numbers and draw the list as an extra annotation feature that you could move to an open area on the map. While that worked well enough as an exercise, the variety of keylist formating options proved prohibitively large to go further with such a tool in ArcMap. I only mention that as proof of such a concept being a fruitful direction to take.

  4. cfrye says:

    Knowing that your map is at just small enough a scale to require a key list is the first trick. I use the Draw Unplaced Labels mode that is on the Labeling toolbar to get a rough idea. If I see clumps of red labels, there’s probably a case for key lists (note that in most cases my street data have been desolved by name and type to ensure extra labels are not being generated because the streets are broken into multiple features).

    Next, to pre-load the workflow, you could either draw graphic boxes around those areas–so you know where to visit once you have created annotation (or rely on turning on the unplaced annoation in the annotation layer properties) and pan from area to area, moving the labels and editing them to have the number, and then creating new annotation for the numbers to place on the streets.

    The problem with that approach comes when you have a fairly large area to map–maybe as a mapbook or map series. Then it would be nice to know where all the congested areas are located. One idea there is to convert the streets (again dissolved by name and type) to points and then use the cluster analysis tools (spatial statistics toolbox) to find clusters. Find the level of clustering that corresponds with the clumps of unplaced labels that require key lists, i.e., finding the meaningful cluster tolerance. Then you can summarize the cluster data (with high enough tolerances) by cluster number and get a checklist to follow.

    At one point, we prototyped a keylist tool in ArcObjects which would take the selected annotation features, sort, number and replace the labels with numbers and draw the list as an extra annotation feature that you could move to an open area on the map. While that worked well enough as an exercise, the variety of keylist formating options proved prohibitively large to go further with such a tool in ArcMap. I only mention that as proof of such a concept being a fruitful direction to take.