Multiscale Design for The National Map of the United States: Road Thinning for Topographic Mapping

Cynthia A. Brewer, PSU Lawrence V. Stanislawski, CEGIS-USGS Barbara P. Buttenfield, CU-Boulder Paulo Raposo, Penn State Kevin A. Sparks, Penn State Michael A. Howard, CEGIS-USGS

AutoCarto, September 2012

Cartographic uses of Thin Road Network tool for automated national mapping: - elimination within a road category - matching scale to thinning level - using thinning for hierarchy - using thinning in labeling

Multiscale design context

• Draft design for mapping The National Map data from the U.S. Geological Survey (USGS)

• Automated map production from ArcGIS (no by-hand edits)

• Design through scales of 1:20 000 – 1:1 000 000

• Mapping sample of ten subbasins throughout country

39%! Elimination decisions in ScaleMaster

Remove features for multiscale mapping

Select, Eliminate, Refine,

Filter (e.g., definition query on size)

Prune (USGS hydro tools)

Thin (ArcGIS Thin Road Network tool)

Concept is not treated systematically in literature or tools

Be systematic about use of elimination through scale (39%!)

Database-driven cartography needs importance attributes for all feature types to drive elimination of labels and features

Atlanta GA study area Three road density partitions 393,920 road Segments TomTom data Area of 61 topo quads

TomTom sample: 55,261 roads, 6,043km length

“Thin Road Network” tool

Example: 500m road length thinning

All roads

Thinning run with 10 minimum road lengths for this study: 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 5000, 6000, 7000, 14000

500m road length thinning

1500m

3000m

6000m

All roads

At 300K, Esri recommends a minimum road length of 3000m for organic road patterns and 6000m for gridded road patterns.

Matching scale to thinning level

Minimum

length

(in meters)

Total road length (km)

Whole

Clip

all roads 6,043

500 4,220

1000 3,190

1500 2,726

2000 2,442

2500 2,299

3000 2,187

3500 2,106

4000 2,034

5000 1,877

6000 1,775

7000 1,672

14000 1,144

1500m thinning

All roads

Radical Law use

• Invert Radical Law equation (Töpfer and Pillewizer, 1966)

• Apply to road length, rather than number of roads

• Consistent with CEGIS approach to pruning stream channels

Denominator of target scale =

(length of source roads)2 x denominator of source scale

(length of target roads) 2

Example calc for 1500m thinning:

117,953 = (6043) 2 x 24,000

(2726) 2

Use scale 1:118,000 for roads thinned with 1500m length

Minimum

length

(in meters)

Total road length (km)

Whole

Clip

all roads 6,043

500 4,220

1000 3,190

1500 2,726

2000 2,442

2500 2,299

3000 2,187

3500 2,106

4000 2,034

5000 1,877

6000 1,775

7000 1,672

14000 1,144

All roads

1500m thinning

Minimum

length

(in meters)

Map scale based on Radical Law

(scale denominator in thousands)

Whole

Clip

all roads 24

500 49

1000 86

1500 118

2000 147

2500 166

3000 183

3500 198

4000 212

5000 249

6000 278

7000 314

14000 670

Example calc for 7000m thinning: 313,601 = (6043) 2 x 24,000

(1672) 2

Use scale 1:314,000 for roads thinned with 7000m length

Using thinning for hierarchy

Road thinning for hierarchy

U.S. and state routes shown with darker, wider lines

___ 3000m

thinning on local roads

___ 14000m thinning on local roads

Road thinning for hierarchy

U.S. and state routes shown with darker, wider lines

___ 3000m

thinning on local roads

___ 14000m thinning on local roads

Eliminate roads with invisibility = 1

Eliminate roads with invisibility = 1

Seeking continuous attribute: Thin Sum

Invisibility attribute is zero or one for individual thinning levels Thin Sum ranges from 0 to 11 (add up all the 1s for feature)

Use Thin Sum as importance attribute for classes within category (local roads)

‘Ladder’ process the thinnings before summing

Using thinning in labeling

Labeling through scale

Kevin Sparks

Labeling through scale

Kevin Sparks

Three thin levels guide Maplex

All-in-one Maplex

Three thin levels guide Maplex

All-in-one Maplex

Labeling through scale

Kevin Sparks

Three thin levels guide Maplex

1:50,000

All-in-one Maplex

1:50,000

All-in-one Maplex

Three thin levels guide Maplex 1:50,000 Kevin Sparks

Draft topo designs

Paulo Raposo

Elimination within a road category Matching scale to thinning level

Using thinning for hierarchy Using thinning in labeling

Elimination within a road category Matching scale to thinning level

Using thinning for hierarchy Using thinning in labeling

Partitioning thinning by density

Acknowledgements USGS funding 2007 to present, Lynn Usery, Center of Excellence for

Geospatial Information Science (CEGIS), and 2010-11, Mike Cooley

Resources

CEGIS-USGS:

cegis.usgs.gov

Project resources:

ScaleMaster.org

Gould Center, Penn State:

NationalMapping.us

Meridian Lab, Boulder:

greenwich.colorado.edu

Chris Anderson Tarver, Mike Gleason CU-Boulder Edie Punt, David Watkins, Marc-Olivier Briat Esri

Thank you to additional Penn State RAs…

Rick Fourroux, Jay McGilloway, Steve Butzler, Andy Stauffer, Jim Thatcher, Doug Minnigh, Chelsea Hanchett, Halina Sundy, Rob Roth, Mamata Akella, Jess Acosta

Partitioning thinning by density

Example Iowa roads intended for 1:24,000 display and shown at 1:375,000

Thinned using 7500m minimum itinerary length--excessively homogeneous

Minimum

length

(in meters)

Map scale based on Radical Law

(scale denominator in thousands)

Whole

Clip

Dense

partition

Sparse

partition

all roads 24 24 24

500 49 52 41

1000 86 91 69

1500 118 125 94

2000 147 155 119

2500 166 175 132

3000 183 196 141

3500 198 210 154

4000 212 226 163

5000 249 267 189

6000 278 299 210

7000 314 341 226

14000 670 720 505

1500m thinning

All roads

Minimum

length

(in meters)

Map scale based on Radical Law

(scale denominator in thousands)

Whole

Clip

Dense

partition

Sparse

partition

Pairing similar scales in

different rows:

all roads 24 24 24

500 49 52 41

1000 86 91 69 dense thinned at 1000m

1500 118 125 94 sparse thinned at 1500m

2000 147 155 119

2500 166 175 132

3000 183 196 141

3500 198 210 154

4000 212 226 163

5000 249 267 189

6000 278 299 210

7000 314 341 226

14000 670 720 505

Partitioned thinning directed by Radical Law for 1:93,000 Combine 1500m and 1000m (cyan in denser partition)

Minimum

length

(in meters)

Map scale based on Radical Law

(scale denominator in thousands)

Whole

Clip

Dense

partition

Sparse

partition

Pairing similar scales in

different rows:

all roads 24 24 24

500 49 52 41

1000 86 91 69

1500 118 125 94

2000 147 155 119

2500 166 175 132

3000 183 196 141

3500 198 210 154

4000 212 226 163 dense thinned at 4000m

5000 249 267 189

6000 278 299 210

7000 314 341 226 sparse thinned at 7000m

14000 670 720 505

Partitioned thinning directed by Radical Law for 1:226,000 Combine 6000m and 4000m (cyan in denser partition)