Kern

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Down in the Trenches

Automating Label Placement in

Dense Utility Maps

Jill Phelps Kern

The Map Label Placement Problem

• Definition

• Literature review

• Research problem

• Approach and timeline

3

Problem Definition

The Map Label Placement Problem

Placing map feature labels

• legibly

• without overlap (features / other labels)

• maintaining visual association of labels with their features

4

Densely Labeled Maps

5

Densely Labeled Maps

6

Literature Review Themes

Label Placement

• rules

• quality metrics

• algorithms

7

Label Placement Rules

• Area features

• Point features

• Line features

Label placement most difficult

Label placement least constrained

8

Label Placement Rules

Menemsha

Lakeview

Lakeview

Lake Winnipesauke

Potomo

Potomo

Franklin County

Davis County

9

Sources: Imhof (1962, 1975); Wood (2000)

Label Placement Quality Metrics

• Aesthetics

• Label visibility

• Feature visibility

• Association

Based on Van Dijk et al.

(1999) i

City

ATown

BTown

City

Peak

BTown

R i v e r

ATown

10

Label Placement Quality Metrics

• Aesthetics

• Association

5 of 20 papers reviewed

• Label visibility 20

• Feature visibility 10

11

11

Automating Label Placement

• Area features

• Point features

• Line features

Label placement most difficult

Frequent research target for label placement automation

Label placement least constrained

12

Automating Label Placement

• Area features

• Point feature label placement

• Line features models algorithms

13

Automated Point Feature Label Placement

Models

Discrete label position priorities: Yoeli (1972)

2

4

1

3

6

7

8

Slider model: Van Kreveld et al. (1999)

5

Continuous circumferential movement: Hirsch (1982), Kameda & Imai (2003)

14

Automated Point Feature Label Placement

Algorithms

Local Search

Global Optimization

15

Automated Point Feature Label Placement

Algorithms

Local Search

• Rule-based exhaustive search

• Gradient descent

Global Optimization

• Force-directed

• Simulated annealing

16

Local Search

Algorithms

Exhaustive Search

Rule

Rule

Rule

… x

• Place labels according to rules until violation

• Backtrack and adjust to maximize number of labels placed

17

Local Search

Algorithms

Gradient Descent

• Develop initial label placement

• Compute overlap vectors to guide next movement

• Iterate From Hirsch (1982), p. 13

18

Local Search

Algorithms

Gradient Descent

• Develop initial label placement

• Compute overlap vectors to guide next movement

• Iterate

• Can cycle between local minima (a) and (b)

(a) without finding preferred placement (c)

From Hirsch (1982), p. 13

(b)

(c)

From Christensen et al.

(1995), p. 213

19

Automated Point Feature Label Placement

Algorithms

Local Search

• Rule-based exhaustive search

• Gradient descent

Global Optimization

• Force-directed

• Simulated annealing

20

Global Optimization

Algorithms

Force-Directed

From Stadler et al.

(2006), p. 211

21

Global Optimization

Algorithms

Simulated Annealing

Based on Zoraster (1997) and Christensen et al.

(1995)

22

Automated Label Placement

Software

Yoeli priorities

Imhof (and others’) labeling rules

Iteration and backtracking

9.2

Label / feature visibility

Slider models

Simulated annealing

Optimization

Association

Aesthetics

Force-directed methods

23

Project Objectives

Evaluate the automated labeling capabilities of current GIS software when applied to dense maps

Identify factors which necessitate manual label placement

24

Project Context

Town of Concord Sewer Map Book

25

Sewer Infrastructure Features

Point feature: Sewer manhole

Attributes: Facility ID , station number , rim elevation , invert elevation

26

Sewer Infrastructure Features

Line feature: Sewer main

Attributes: Size, material

(VCP = vitreous clay pipe)

27

Sewer Infrastructure Features

Line feature: Sewer main

Attributes: Slope and slope direction

28

Sewer Infrastructure Features

Line feature: Sewer tie

Attribute: Service number

29

Sewer Labeling Quality Metrics

Importance: Critical – Major – Minor

A. Number of Labels Placed

• Total and % of ideal

• Minimal leader length

B. Labels in Preferred Position

• Point (manhole)

• Line (sewer mains & ties)

• Area (streets)

C. No Overlap

• Label-label

• Label-sewer tie

30

Sewer Labeling Quality Metrics

Importance: Critical – Major – Minor

A. Number of Labels Placed

• Total and % of ideal

• Minimal leader length

B. Labels in Preferred Position

• Point (manhole)

• Line (sewer mains & ties)

• Area (streets)

C. No Overlap

• Label-label

• Label-sewer tie

31

Sewer Labeling Quality Metrics

Importance: Critical – Major – Minor

A. Number of Labels Placed

• Total and % of ideal

• Minimal leader length

B. Labels in Preferred Position

• Point (manhole)

• Line (sewer mains & ties)

• Area (streets)

C. No Overlap

• Label-label

• Label-sewer tie

32

Approach and Timeline

1. Prepare for research (Dec – Feb)

2. Conduct research (Mar – May)

3. Develop conclusions (Jun – Jul)

4. Present findings (Aug – Oct)

33

1. Prepare for Research

• Conduct literature review - COMPLETE

• Select case study maps - COMPLETE

• Design label classes, styles and hierarchy / weighting

- COMPLETE

• Develop label placement quality metrics - COMPLETE

34

Research Preparation

35

2. Conduct Research

A. Automated Labeling

Apply automated ESRI labeling tools to case study maps

Standard labeling engine

• Maplex

Measure quality of automated results

• Iterate to improve quality using automated tools

Select highest quality result (standard vs. Maplex) for remaining steps

36

2. Conduct Research

B. Manual labeling

• Complete manual adjustments

• Measure quality of manual results

• Compare quality of final automated vs manual

37

3. Develop Conclusions

• Strengths and limitations of current automated labeling tools

• Conditions under which manual placement becomes preferable

• Research limitations and potential for future study

38

4. Present Findings

• Prepare for conference presentation

• Present at NACIS 2007 conference

39

Preliminary Findings

Standard Labeling Engine Maplex

Poor Acceptable Ideal

40

Questions?

41

References

Christensen, Jon, Joe Marks, and Stuart Shieber. 1994. Placing text labels on maps and diagrams. Graphics Gems IV , Cambridge MA:

Academic Press, 497-504.

Christensen, Jon, Joe Marks, and Stuart Shieber. 1995. An empirical study of algorithms for point-feature label placement. ACM Transactions on

Graphics (14)3: 203-232.

Cook, Anthony C. and Christopher B. Jones. 1990. A Prolog interface to a cartographic database for name placement. In Proceedings of the

International Symposium on Spatial Data Handling , International Geographical Union and International Cartographic Association, pp. 701-710.

Doerschler, Jeffrey S. and Herbert Freeman. 1992. A rule-based system for dense-map name placement. Communications of the ACM (35)1: 68-

79.

Ebner, Dietmar, Gunner W. Klau and Rene Weiskirscher. 2003. Force-based label number maximization. Technical Report TR 186-1-03-02 ,

Vienna: Vienna University of Technology.

Edmondson, Shawn, Jon Christensen, Joe Marks, and Stuart M. Shieber. 1996. A general cartographic labeling algorithm. Cartographica (33)4:

13-23.

Freeman, Herbert and John Ahn. 1984. AUTONAP – an expert system for automatic name placement. Proceedings of the International

Symposium on Spatial Data Handling , International Geographical Union and International Cartographic Association, pp. 544-569.

Freeman, Herbert and John Ahn. 1987. On the problem of placing names in a geographic map. International Journal of Pattern Recognition and

Artificial Intelligence 1(1): 121-140.

Hirsch, Steven A. 1982. An algorithm for automatic name placement around point data. The American Cartographer 9(1): 5-17.

Imhof, Eduard. 1962. Die Anordnung der Namen in der Karte [Positioning names on maps]. Internationales Jahrbuch fur Kartographie, vol. 2,

Verlagsgruppe Bertelsmann GmbH/Kartographisches Institut Bertelsman, pp. 93-129.

Imhof, Eduard. 1975. Positioning names on maps. The American Cartographer 2(2): 128-144.

Jones, Christopher B. 1989. Cartographic name placement with Prolog. IEEE Computer Graphics and Applications 9(5): 36-47.

Kameda, Takayuki, and Keiko Imai. 2003. Map label placement for points and curves. IEICE Transaction Fundamentals E86-A(4): 835-840.

Stadler, Georg, Tibor Steiner and Jurgen Beiglbock. 2006. A practical map labeling algorithm utilizing morphological image processing and forcedirected methods. Cartography and Geographic Information Science 33(3): 207-215.

Van Dijk, S., M. Van Krefeld, Tycho Strijk, and Alecander Wolff. 1999. Towards an evaluation of quality for label placement methods.

Proceedings of the 19th International Cartographic Conference and 11th General Assembly, ed. by C. P. Keller, Ottawa, Ontario, pp. 57-64.

Van Kreveld, M., Tycho Trijk and Alexander Wolff. 1999. Point labeling with sliding labels. Computational Geometry 13: pp. 21-47.

Wood, Clifford H. 2000. Descriptive and illustrated guide for type placement in small scale maps. The Cartographic Journal 37(1): 5-18.

Yoeli, P. 1972. The logic of automated map lettering. The Cartographic Journal 9(2): 99-108.

Zoraster, Steven. 1997. Practical results using simulated annealing for point feature label placement.

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Science 24(4): 228-238.

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