Wednesday, September 23, 2009

Atlanta Flooding: Satellite Images from DigitalGlobe

A colleague passed along a few images of the flooding in Atlanta, which DG provided permission to post. This imagery truly demonstrates the value of satellite imagery and remote sensing in general for crisis / rapid response situations - not to mention how bad the flooding in Atlanta is.

Click on the images below for higher-detail versions.

Six Flags 9/22/09

Satellite Image Credit: DigitalGlobe


Lithia Springs 9/22/09

Satellite Image Credit: DigitalGlobe

3D GIS Seminar

Just a quick note to say that the Bentley Seminar on "Bentley 3D GIS" is now available here. You need to register for both their site and the seminar, but it is quick and painless. The main focus on the seminar is (a) the need for 3D GIS for infrastructure and other applications and, (b) Bentley's tools for integrating GIS, CAD, and BIM data for city modeling applications. This focused on Bentley Map as a primary tool for data integration, modeling, and visualization. CityGML export has been added, which may make Bentley Map one of the earliest systems from a major vendor to support the standard.

It's great to see more people thinking about 3D cities beyond just the physical models. It will be interesting to see who will be the first to market with a system that integrates model creation and collection (e.g. collect buildings in stereo, from LIDAR, or automated techniques) along with urban information management.

Monday, September 21, 2009

Photogrammetry News: Photogrammetric Week 2009

It has been a busy summer and as a result I haven't had much time for keeping up to date with The Fiducial Mark. But with an inter-continental move from Belgium back to Canada wrapped up, there is a lot of news in the mapping business to comment on.


One major event that comes along every couple years is Photogrammetry Week in Stuttgart, Germany. This event, which was held a few weeks ago on September 7-11, is a great forum for learning about the latest developments in airborne sensors, software, and general industry trends. For those of us that didn't get a chance to make it over, the Institute for Photogrammetry at the Universit├Ąt Stuttgart hosts a web-site containing the agenda, photos, and papers from the conference. The "Papers of the 52nd Photogrammetric Week" section contains a gold-mine of information, and a review of the articles provides a look at where things are at in the industry today.

Papers are divided into four sections:

Introduction: Presentation papers from the University of Stuttgart, Hexagon (Leica Geosystems and ERDAS), Intergraph, Vexcel Imaging (Microsoft), Trimble Geospatial, and IGI. These papers provide company overviews, organizations updates and a common focus on sensor updates (e.g. ADS80, UltraCamXp, etc).

Image-based Data Collection: these papers largely focus on airborne camera systems. One interesting paper is "Digital Airborne Camera Performance - the DGPF Test" by Michael Cramer. DGPF is the German Society of Photogrammetry, Remote Sensing, and Geoinformation. The paper discusses an ongoing project evaluating the strengths and weaknesses of various digital sensors, covering systems from Intergraph, Leica Geosystems, Jenaoptronik, Vexcel Imaging, IGI, Rolleimetric, and DLR Munich. The project involved data collection flights over a well-controlled test site near Stuttgart. In reading the paper, it becomes clear how difficult it is to perform precise apples-to-apples tests between systems - given how many factors can impact the performance of a system (e.g. weather). The paper focuses on geometric accuracy and provides detailed information on the studies conducted thus far. It will be interesting when results are available from the radiometry working group, because this is an area where there are a number of differences between the above sensor systems.

Other interesting papers in this section are "Oblique Aerial Photography: a Status Review", and "The Bright Future of High Resolution Satellite Remote Sensing - Will Aerial Photogrammetry Become Obsolete?" The oblique paper is a good reminder of how Pictometry has come to dominate this particular niche. While I don't believe aerial photogrammetry will become obsolete anytime soon, the second paper raises some great points on the development of satellite-based photogrammetry.

LiDAR: Airborne, Terrestrial and Mobile Applications: numerous papers on both hardware and processing developments for airborne and terrestrial LIDAR applications. The intriguing topic here is how mobile laser scanning is becoming increasingly relevant (Gene Roe adds insight on this topic as well here).

Value-Added Photogrammetry: articles providing a look at where current photogrammetric processing research is focused. The topics range from standards (CityGML), sensor to internet workflows (ERDAS is in a unique position of being the only company that can really offer a solution that starts with data capture and ends up with on-line data delivery and web services), digital image matching, cultural heritage, and more. Automated terrain extraction from stereo imagery is being pursued with renewed vigor, and it is good to see standards appear on the radar as well. Although I failed to see any developments on standards with regards to photogrammetric metadata, it will be great progress if CityGML gains momentum for one of photogrammetry's primary data products: 3D models.

Kudos to the conference organizers for sharing the conference materials - it is a valuable resource and greatly beneficial to the broader geospatial community as well. Sensor data and photogrammetric processing technology is the root of 3D geo-information, and it will only be a matter of time before these technologies embed themselves in an even broader array of applications.