Corridor Boundary Map

The orthophotographic image base map of the City of Austin was added to the view as an Image data source.

This map was created by selecting the road segment links from Koenig Land to 45th Street along Burnet Road using the button.

These selected links were then converted to a new shapefile and coded red so that it was easily viewed. 

A layout was created to show a large portion of the City of Austin to orient the viewer.  A smaller zoomed picture was then added with street labels to give the viewer a better understanding of the layout of the selected corridor.  Street labels were added using the button.

Neighborhood Association Map

This map was created by selecting the polygons for each neighborhood association adjacent to the selected Burnet Road segment using the button.

After each neighborhood association was selected a new shapefile was created and each neighborhood association was represented with a unique value.

Land Use Map

This map was created using the 1995 Land Use map provided by the City of Austin.  In planning, there are acceptable colors used to represent each land use.  To change the colors of each land use the Symbol Window Color Palette was used.

Facility Proximity Map

To create the facility map, first data was collected about popular neighborhood pedestrian destinations and transit stops along the corridor.  The neighborhood destinations were then represented by their building footprint.  Each footprint was selected with the   button and a new Shapefile of these buildings was created.  To add the transit stops to the theme the   button was used.  Points were added to the view and the color palette was used to change the color of the northbound stops to red.

Topic 2:  Pedestrian Walkable Catchments

The method used to determine the Burnet Road walkable catchments is presented by the Congress for the New Urbanism in a Transportation Tech Sheet entitled "Ped Sheds."

According to the Tech Sheet, Ped Sheds are "maps showing the actual area within a five- to ten- minute walking distance from any activity center or transportation stop."  This is a technique used for evaluating how easy it is for a pedestrian to move through an urban area to access neighborhood activity centers.  This method will be applied to facilities and transit stops along the Burnet Road Corridor to determine its accessibility to pedestrians.

Walkable catchments or ped sheds are the actual area within a five- or ten- minute walking distance as a percentage of the theoretical or "as the crow flies" walking distance.  A five-minute walking distance is typically one-quarter mile and a ten-minute walking distance is one-half mile.  The higher the resulting percentage the better the walkability.  A target for good accessibility by pedestrians is 60%.

To determine the walkable catchment areas along Burnet Road public facilities and businesses representing neighborhood destinations were chosen.  In addition transit stops along the study corridor were used.  After the locations were chosen, the Network Analyst Extension was utilized to determine the walkable catchment.  Within Network Analyst three options for analysis exist: Find Best Route, Find Closet Facility, and Find Service Area.  The Find Service Area function is utilized to determine the walkable catchments.

The following steps were followed to determine the walkable catchment for the North Loop Branch Library.

Step 1) Set-Up ArcView Themes 

A)  Add Themes to View

1995 Land Use (Polygon)

Street Address Utility (Line)

B)  View Properties Dialog Box

Change Map Units to Feet

Change Distance Units to Feet

Step 2) Perform Network Analysis 

A) Add Network Analyst Extension from File Menu 

B) From the Network Menu choose Find Service Area Option

Choose this option when the Street Address theme is active.

C) Choose Cost Field

In the Properties Dialog Box choose <Line_Length> as the cost field because this will allow a one-quarter mile service area to be used.

D) Locate Site

Use the button to enter the address of the Library.  This will allow the program to automatically know where to begin the network.  

E) Specify Area

By double clicking in the cost field the distance that is desired can be entered.  For the walkable catchment 1320 feet (one-quarter mile) will be used in the cost field.

F) Solve

When all necessary input is entered the   button is pressed and the network is drawn.  Two new themes are created when this function is performed: sarea1 and snet1.  These themes represent a polygon area that encompasses the line theme drawn one-quarter mile out from the site.   

Step 3) Create Walkable Catchment Shapefile 

A) Locate One-Quarter Mile Radius

Using the button a one-quarter mile radius circle is drawn around the library.  This represents the 125-acre area that will be used to determine the walkability percentage.

B) Find the Parcels Touching the Network

Activate the Library Network Theme.  From the Theme Menu choose Select by Theme.

Add a New Set and convert this set to a new shapefile called LibraryCatchment.shp.   

A selection distance of 50 feet is used to insure that adjacent polygons are selected.  In the polygon theme the road network is drawn as a polygon that cane be up to 50 feet wide; by defaulting to a selection distance of 50 feet the polygons adjacent to the network are selected.

Step 4) Edit the New Shapefile

The new shapefile includes the road network polygon.  This is not an area that should be included in the area used to calculate the walkable catchment.  The road network areas are deleted because the walkable catchment should only count the area of land use for dwellings or businesses but should not include public space.

A) Open the LibraryCatchment.shp Attribute Table

From the Table Menu select Start Editing.

B) Delete Road Network

In the attribute table delete all records with LU_Code = 800.  Code 800 represents the Transportation land use.  From the Table Menu select Save Edits.  

Step 5) Calculate Walkable Catchment Area  

Use the Button to calculate the total area of the LibraryCatchment.shp shapefile.  

The total area calculated by this function was 2,020,409 square feet.  To determine the final percentage this must be converted to acres.

2,020,409 sf  x 1 acre/43,560 sf = 46.4 acres

A one-quarter mile circle represents 125 acres.  To determine the walkable catchment the following calculation is performed.

(46.4 acres / 125 acres) x 100 = 37.1 %

Step 6) Repeat Procedure for Other Facilities and Transit Stops 

For the other facilities the same steps outlined above were followed.  For transit stops two walkable catchments were determined:  a five-minute and a ten-minute.  It is assumed that people will walk farther to reach a transit stop therefore the ten-minute catchment is used.

Summary and Conclusions

For three neighborhood destinations and two transit stops along the Burnet Road Corridor walkable catchments were determined.  The following Table shows the results of these calculations.  Each location is a link to a drawing that illustrates the specific walkable catchment for that location.

Location 

Walkable Catchment Percentage 

HEB Grocery Store

North Loop Branch Library

Upper Crust Bakery

47.4% (35.7%*)

37.1%

77.4% (43.1%**)

*This is the walkable catchment for the HEB excluding the Lamar Junior High School.

**This is the walkable catchment for the Upper Crust Bakery excluding the Texas School for the Blind.

Transit Stop 

Walkable Catchment Percentage 

49th Street at Burnet Road 

Koenig Lane at Burnet Road

79.2% (45.0%*)

51.6% (39.9%**)

48.1% (39.5%*)

50.2% ( 47.2%**)

*This is the walkable catchment for the stop excluding the Texas School for the Blind.

**This is the walkable catchment for the stop excluding the Lamar Junior High School.

The only activity center with a walkable catchment above the target is the Upper Crust Bakery when the Texas School for the Blind is included. These results show that the activity centers along the corridor have mediocre pedestrian accessibility.  This might be attributed to large lot sizes or the non-grid like street pattern of the corridor.  The northern portion of the corridor has many angled and curved streets and that reduces its accessibility as shown by the HEB walkable catchment. The third walkable catchment represents a centrally located pedestrian activity center on the corridor, the North Loop Branch Library. 

For the transit stops along the corridor five- and ten- minute catchments were found.  It is generally accepted that that pedestrians will walk further to a transit stop, therefore the ten-minute catchment is also applied to the transit stops.  Typically, the five-minute catchment is represented in purple and the ten-minute catchment is represented in light blue.  It can be seen in the walkable catchment at Koenig Lane  that the large lot sizes near the transit stop do not provide many destinations accessible by pedestrians in the five-minute catchment.  Although, in the ten-minute catchment more destinations are accessible because they are mainly residential lots.

Concerns with Walkable Catchment Method 

The method used to determine the walkable catchments on Burnet Road uses the street network rather than the sidewalk network to determine accessibility.  This may introduce errors into the calculation in areas of poor sidewalk continuity and poor ADA compliance.  The walkable catchments may not accurately represent the true accessibility of an activity center or transit stop if the street network is used. 

Although, if this method is modified to use the sidewalk network issues still will prevent accurately measuring the accessibility.  In the case of a using a sidewalk network, jaywalking and intersections without crosswalks cannot be represented.  Also, non-compliant ADA sidewalks cannot be modeled in this method and without sidewalk ramps the walkable catchment would not be truly accessible to all pedestrians.

Conclusions on GIS use for Background Data

Sources

Congress for the New Urbanism.  "Ped Sheds."  Transportation Tech Sheet. http://www.cnu.org/tech_sheets/ped_sheds.html

ESRI. ArcView GIS:  The Geographic Information System for Everyone. 1996.

ESRI. ArcView Network Analyst. 1996.

Paper and Presentation

PowerPoint Presentation