DVAEYC IREG Meeting

2 June 2010

Tamara Manik-Perlman, Azavea (formerly Avencia)

CommonSpace:A Shared Transitspace Collaboration Platform

William Penn Foundation

Sustainable Business Network of Greater Philadelphia

NPower PA

Azavea (formerly Avencia)

Partners

Vision

Provide consumers with tools to make choices that support local living economies

Promote sustainable transit

Support neighborhood corridor economic development

Promote Philadelphia as a sustainable city

Project Goals

1.Sustainable transit visualization

2.Destination discovery on a map, aggregated from curated web sources

3.Real-time collaboration

CommonSpace Features

See and searchwhere you can go by

walking,biking

&public transit.

1.Transit Visualization

Discoverevents,

“local treasures”&

sustainable businessesfrom a variety ofcurated sources.

2. Destination Discovery

Collaborate on ashared map

to find and choose destinationsat a convenient distance

from everyone in a group.

3. Collaboration

Planning what to do tonight with your friends who are online at the same time

Planning a weekend adventure over the course of a week

Planning a multi-stop shopping trip

Finding a location for a house based on work, school, and other locations

Publishing an itinerary online, e.g. events at a multi-day event

How could this be used?

Walkthrough

User Narrative

I want to go out and find a fun activity within walking distance.

I invite a friend to come with me, and we find somewhere to eat that is located conveniently for both of us.

Demonstration

http://commonspace.us/CommonSpace.html

Data & Technology

Open-source multi-modal trip planner

Uses Dijkstra’s shortest path algorithm

Developed by Brandon Martin-Anderson

http://bmander.github.com/graphserver

Graphserver

Transitspace Calculation Methodology

1.Gather data

2.Build graphs

3.Generate shortest path tree

4.Calculate contour raster

5.Convert raster to three-band bitmap

Street networkOpenStreetMap (XML)

DEMUSGS NED

Transit dataGoogle’s General Transit

Feed Specification (GTFS)

1. Gather Data

Import data into Graphserver

Run a utility to create a network for each transit method; include additional parameters such as directionality or weighting

i. Walkingii. Bikingiii. Mass Transit

2. Build Graphs

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i.

ii.

iii.

Select a starting point and a transit method

Traverse the appropriate graph

Assign a time distance to each vertex on the network

3. GenerateShortest Path Tree

Source: Brandon Martin-Anderson

Using values of vertices, calculate a contour map of travel times

Output result as a raster

4. CalculateContour Raster

Source: Brandon Martin-Anderson

Convert single-band raster to a three-band (RGB) bitmap

5. Convert to Bitmap

Transitspace Visualization

Source: Brandon Martin-Anderson

1.Overlay the transitspace bitmap on the map

2.Move the slider to control travel time

3.Translate travel time to a color value

4.Display transitspace: visualization is controlled by a Flex image filter, which displays only those values below a given color value threshold

Search Area Server Geoprocessing

1.Move the slider to control travel time

2.Reclass the raster into binary values: 1 for values below the selected time, 0 for those above

3.Convert cells = 1 to a vector polygon with a unique ID

4.Calculate search area, or commonspace, as the intersection of one or more transitspace polygons

Feed Search

Feeds come in many types Event listings (API) Curated blogs (GeoRSS) Static databases of destinations (API)

CommonSpace calls web services differently depending on their requirements

Point-in-polygon search Pass in an extent, filter returned results by the

search area

Questions?

Tamara Manik-Perlman, Azavea

tmanik-perlman@azavea.com

DVAEYC IREG Meeting

2 June 2010

We do other work too…

We do other work too…

Transitspace Visualization

1.Overlay the transitspace bitmap on the map

2.Move the slider to control travel time

3.Translate travel time to a color value

4.Display transitspace: visualization is controlled by a Flex image filter, which displays only those values below a given color value threshold

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