Lidar + OPALs geolunch and workshop next week!

Full waveform lidarOur colleague Bernhard Hofle from the University of Heidelberg will be here next week as part of an international exchange project: Airborne Laser Scanning for 3D Vegetation Characterization: Set-up of an International Signature Database. Bernhard is interested in Open Source GI and Spatial Database Management Systems, Object-based image and point cloud analysis, radiometric calibration of full-waveform airborne LiDAR data, and other topics.

Bernhard is part of a group that now has one of the first Terrestrial Laser Scanning (TLS) systems worldwide with full-waveform recording capability (upgraded Riegl VZ-400). Deeper understanding and substantially improved analysis of the laser shot backscatter of natural objects by having direct access to full-waveform signatures and physical observables are expected. The unique system will be applied in new research projects dealing with the extraction of 3D geoinformation in e.g. precision farming, geoarchaelogy, geomorphology and forestry. Furthermore, an extensive web-based database of reference signatures for known objects will be developed based on calibrated waveform features derived by TLS.

He is a leader in analysis of discrete and waveform lidar data in urban and forest applications and one of the developers of the cool OPALS lidar software. He'll be giving a geolunch and a workshop afterwards on the software. The geolunch is 1-2, then we will stick around and learn about OPALS.

40 Years of Las Vegas Growth Visualized via Landsat

NASA recently released a time-lapse video of false-color Landsat imagery from 1972-2010 for Las Vegas showing the city’s sprawling growth. For more on the video and data click here.

The structure of a city via Twitter

From Mashable Tech.

Check out this gorgeous visualization of NY City's tweetopolis from Oakland-based programmer Eric Fischer.

He plots out the motion of New Yorkers using public tweets on Twitter with geotags from May 2011 until January.

The project lays out around 10,000 geotagged tweets and 30,000 point-to-point trips in cities like New York City to plot the flow of people in terms of favored paths. In his map of NYC, seen above, there is a huge ink blot lining Broadway; as we’ve long suspected, it looks like the busy avenue is the backbone of the city.

Using a base map from OpenStreetMap, he drew out transit paths using Tweets. Movements are indicated on the geolocation of a Tweet, with an individual’s start point marked with one geotagged Tweet and ending with the next geotagged Tweet. This is what creates a mass of traffic routes.

Similar viz of the east bay“If you just draw lines from the beginning to the ending of each trip, you get a big mess, so the challenge is to come up with more plausible routes in between,” Fischer told Mashable. “That is where the 10,000 individual geotags come in, the most plausible routes are ones that pass closely through places that other people have been known to go.”

Fischer used Dijkstra’s Algorithm to calculate what exactly to map out. For those of who haven’t thought about math since high school algebra, that’s an equation that maps out the shortest path between two points on a graph. For this project, the equation pointed to the relevant paths to map out a city’s most dense corridors.

This might be of use for our mobility project with our space.

More here.

mapping gas leaks in Boston

The Google Earth image above shows shafts of bright green indicating natural gas leaking around BU's Charles River Campus. If there are multiple leaks, the display “looks like a stock market index during a busy day,” says Nathan Phillips. Photo courtesy of Nathan Phillips and Picarro, Inc.This is a very interesting report about work at BU Geography and Environment department to map gas leaks across the city. Nathan Phillips, Bob Ackley and Eric Crosson use a Nissan-mounted methane sensor to survey for leaks, and map results on a google earth scene. The accompanying video shows the setup, and discusses some nasty real time implications for trees as gas replaces oxygen in the soil. Also, this is just nuts to think of how much wasted gas is going up in a typical city. Yikes!

MIT releases new Urban Network Analysis Tool for ArcGIS 10

The MIT City Form Research Group recently released a new open-source plugin for ArcGIS 10 to perform advanced spatial analyses on network data such as urban street networks. The tool can give researchers a better understanding of how the spatial layout of cities and their social, economic, and environmental processes affect the way people live in it.

The tool measures reach, gravity, betweenness, closeness, and straightness on spatial networks. This means you can assess the number of services or resources within a certain walking distance and can analyze the volume of traffic along sidewalks and streets. Like other network analysis tools, the tool evaluates network element geometry and distance and distinguishes between shorter and longer links. What is unique about this tool is that it not only operates with node and edge elements like other network analysis tools, but it can also incorporate additional network elements such as buildings. Individual buildings or objects can be characterized within spatial networks and can be weighted to give more or less influence. For example, more populated buildings can be set to have a greater impact on results. The tool can also be used to assess urban growth and change.

Click here for the press release.

Travel time and housing prices map

Our Bay Area regional planning agencies have just released a new interactive map that lets you visualize your housing options given your employment location, income, and desired commute time and mode. It's all part of the regional planning efforts that are happening statewide as a result of SB 375, which requires the integration of housing and land use planning to encourage people to drive less.

The press release gives more details: "If you're in the market to buy a home in the Bay Area, wouldn't it be nice to know how long it would take to commute from neighborhoods in your price range to your work place? Well, now you can, thanks to a new mapping tool on OneBayArea.org.

The interactive map shows you approximately how far you can get from any address within the nine-county region by car, public transit, bike, or on foot, at different times of the day. You can customize your view by the travel time between areas, and the median price of homes in each area."

New BAAMA Journal Published

Volume 5, Issue 1 - Spring 2011

BAAMA is pleased to announce The BAAMA Journal has been published in conjunction with Earth Day.  Special thanks to all our contributing authors and editors.  The BAAMA Journal is a publication that highlights Bay Area people and projects that use geospatial technologies.

IN THIS ISSUE:

• Building Virtual San Francisco: Growing Up With GIS
• DPW Uses LiDAR and a Custom Algorithm for Delineating Drainage Catchments and Hydrologic Modeling
• Preparing Historical Aerial Imagery of Southern California Deserts for use in LADWP's GIS
• Where in the Bay Area