More Roots of Photogrammetry

The blog Modern Mechanix offers another glimpse at the history of photogrammetry today with a scan from the May, 1939, edition of Popular Science. This is the same blog that gave us a glimpse of terrestrial photography-based surveying earlier this month.

The article, Flying Cameras Map America for War, takes a look at the whole process, including collecting imagery from the belly of a military plane, survey parties recording reference points, and stereoscopic photogrammetry back at the base.

The statement of purpose that opens the article feels oddly familiar to a 21st-century geospatial data coordinator:

From aerial photographs snapped by giant bombers soaring four miles above the earth, U. S. Army engineers are compiling maps that will serve as eyes for our armed forces if they ever have to wage a defensive war on American soil.

The image above is a reproduction of "a stereoscopic image of the kind produced by the multiplex aeroprojector used by U. S. Army engineers in making contour maps from aerial photographs." The image at right is an illustration of how one might make sense of "this seemingly meaningless blur of colored lines" to create a topographic map.

I don't think the second image is an actual illustration of a U.S. Army engineer.

NSGIC Mid-Year Reports: Airborne Imagery

Members of the NSGIC Corporate Leadership Council gave a presentation on new developments in airborne imagery and LiDAR. They focused on new technologies and how state GIS Coordinators can take advantage of those technologies. They also listed factors that should be considered in creating RFPs for new imagery.

Craig Molander, from Surdex, spoke about large-format digital cameras. These collect a wide, rectangular image and collect digital data from several sensors at once.

Bob William, from Sanborn, spoke about small-format cameras often used to collect oblique imagery, which has a variety of uses and is growing in popularity.

Dave White, from Fugro EarthData, spoke about the "push-broom" camera, which looks forward, down and back as it moves along. This can help reduce building-lean. It can also make it easier to create elevation data without LiDAR.

Jay Arnold, from 3001, spoke about LiDAR as an adjunct to, or sometimes a temporary replacement for, orthoimagery. He spoke about both topographic and bathymetric LiDAR systems.

Most of the speakers recommended now requesting 4-band imagery, as opposed to just black and white, color, or infrared imagery. This is because most sensors now collect all at once. And there was general agreement that the industry is constantly, and sometimes rapidly, changing.

Update (3/18/08): Presentation materials from this session are now available on-line.

Worth Repeating.....

Frank Taylor, at Google Earth Blog, has an interesting discussion today on the sources of imagery in Google Earth (and, by extension, Google Maps and other ortho-viewing applications) . It bears repeating. Google Earth Blog is not officially connected to Google, but does a nice job of tracking and discussing issues related to Google Earth.

Today's post is actually points to very cool, very "near real-time," but very low-resolution imagery from NASA. But first it takes a detailed look at just how all that "satellite" data gets into Google Earth in the first place. Mr. Taylor explains the (lay-person's version) basics of satellite imaging, aerial photography, ortho-processing, and the complicated web of private- and public -sector partnerships that get the data from data creators and funders to sites like Google Earth.

Not all the imagery in Google Earth comes from satellites. A lot of the imagery comes from aerial photographers mostly in airplanes with special high resolution cameras. Some of the imagery even comes from kites and balloons. Google acquires imagery from a variety of providers. Some of the imagery is given to Google by city or state governments. The age of the imagery varies greatly, but most of the high resolution imagery is between 6 months and 5 years of age. Again, because the imagery comes from a variety of sources, the process to get this imagery into Google Earth is complex and involves a great deal of time and effort.

Thank you. We are all often surprised at how little the data users who interact with imagery via Google Earth, and Maps and their competitors actually know about where the data comes from. Any explanations that get out into the general conversation can only help.

IndianaMap Featured in Television Report

Indiana's Jill Saligoe-Simmel reports on her Professional Geographer blog that the Indiana Geographic Information Council's IndianaMap is featured on the series "Across Indiana" on Indianapolis' WFYI Public Television station.

Dr. Jill reports that the segments are the result of several months of work by members of the Council and feature information on the uses and benefits of Indiana's 2005 very high resolution orthophotography project.

The blog entry includes a few highlights.

Another (the Official) Update on Imagery for the Nation

The first of a planned series of Imagery for the Nation (IFTN) updates has been posted to the NSGIC web site.

Imagery for the Nation is a cooperative effort to make real a vision of "a sustainable and flexible digital imagery program that meets the needs of local, state, regional, tribal and federal agencies."

Update #1 (PDF) looks at several on-going activities related to the effort:

• Work now under way on a Cost Benefit Analysis study.
• Thoughts on the idea from the Western Governors Association.
• Recent discussions on potential funding options.
• Next steps and "what can I do to help?"

One answer to that last question is very simple:

You can assist the implementation of IFTN by showing your support for this initiative. Please have your organization send a letter of support to NSGIC for posting on its web page. You can simply use the format from one of the letters on the site, or create your own format. What’s important is your show of support.

Stay connected to the NSGIC blog and to the IFTN web site for further updates.

An Update on Imagery for The Nation

Ted Koch, NSGIC's lead on the Imagery for the Nation (IFTN) project, has posted an update on the project on the Wisconsin Mapping Bulletin.

He reports that the National Digital Orthophoto Programs Committee (NDOP) which has been focused on IFTN lately, met in May and continued their work to flesh-out what IFTN will mean:

The NDOP committee will be developing over the next six months a much greater level of detail on technical specifications, and program and management issues. Work on these issues will involve federal, state and local government participation.

He also reports on work on a Cost Benefit Analysis of IFTN funded by the USGS and the USDA

The CBA will compare costs over a 10-year period of the way orthoimagery is currently collected and achieved vs. the potential methods that could be possible under the IFTN proposal. The study will also look at overall risks and benefits to the proposed program.

He notes that the analysis is expected to be published this summer.

When We Get Hi-Res Local Imagery Out to as Many People as Possible

Indiana is one of the states that has gotten their high resolution orthophotography added to Google's Earth and Maps systems. The photos are hi-res enough that the image-hunters at the Google Earth Community have spotted an Amish horse and buggy on a rural Indiana road.

As communities will, they looked deeper, researched the presence of the Amish in Indiana, and have collected and published a series of placemarks showing photographic evidence of where a few members of the Amish Community happened to be on an unspecified day in late winter/early spring of 2005.

While I was interested to see Amish folks visible on Google Earth (they are a part of Delaware culture as well), what was coolest about this for me was to see "IndianaMap Framework Data" credited on Google Earth.

Well-played, Indiana Geographic Information Council! (Via Google Earth Blog)

Clearing Up Google's Take on New Orleans

Google now has recent, high resolution, and most importantly, Post-Katrina imagery loaded to Google Maps and Google Earth. This is in response to a recent storm of criticism over the loading of pre-Katrina imagery last fall.

Google took this seriously. John Hanke, the Director for Google Maps/Local/Earth, posted about it this morning on the Official Google Blog (About the New Orleans imagery in Google Maps and Earth).

...we recognize the increasingly important role that imagery is coming to play in the public discourse, and so we're happy to say that we have been able to expedite the processing of recent (2006) aerial photography for the Gulf Coast area (already in process for an upcoming release) that is equal in resolution to the data it is replacing.

Hanke did note that the change to pre-Katrina imagery took place back in the fall of 2006. He expressed some surprise at the very recent storm of controversy.

The folks at Google should recognize the speed that ideas can move on-line, and the momentum they can generate, even when they are very late in getting started.

Update: Adena and her folks over at All Points Blog make a very good point (Will the Google/Katrina Affair Finally Push Metadata on GM/GE?) about the helpful role that metadata might have played in this situation. had there been any metadata.

Comparing the On-Line Map Giants

A frequent topic of conversation among State GIS Coordinators lately has been the relative merits of the big names in on-line mapping.

As in: "What aerial imagery does Google have for my state?"

It's not an idle question. For much of the public, the web-mapping that has come into vogue in the last year is a first entre into GIS and spatial data.

Now, there's Flash Earth, a very simple flash-based interface that allows one to zoom to an area and click between the versions of that area found on Google, Microsoft VE, Yahoo Maps, Ask.com, and others.

As a result, I can now say with some confidence that Google has the most up-to-date imagery for the resort area in coastal Delaware (where I live) of all of these sources. Your results may vary.

Flash Earth describes itself as "an experimental application" and notes that the imagery is used "without official consent" from Google et al. Via LIFEHACKER