The Daily Render

A Digital Scrapbook for the Past, Present, and Future

The 2008 Washington, DC Orthophotography
|| 10/21/2009 || 4:30 pm || 1 Comment Rendered || ||

Screen grab from https://www.nikolasschiller.com/blog/wp-admin/post-new.phpGraphic Converter showing the entire dataset of the 2008 Washington, DC Orthophotography

A couple weeks ago when I was writing the entry about crime in my neighborhood, I discovered that the DC Government’s Citizen Atlas was using aerial orthophotography taken in 2008. I subsequently checked the USGS website to see if they had obtained the dataset, but they were still using the imagery taken in 2005. I decided to e-mail one of my contacts in the Office of the Chief Technology Officer. I asked if the dataset was available to the public or if it was going to be ported over to the USGS’s distribution system, and to my chagrin, the offer was extended to mail me a copy of the entire dataset. About a week later I received the CD in the mail and today I started to explore all the brand new imagery that I now have at my disposal! I now have the ability to use aerial orthophotography of Washington, DC taken in 2002, 2005, and 2008.

I first must note that the roughly 67 gigs worth of aerial orthophotography of Washington, DC was all compressed using the Mr. SID file format and was able fit on one CD-Rom. While that level of digital compression is pretty insane (80 to 1), I still have my reservations about it. Almost two years ago I wrote about how Mr. SID has been the bane of my cartographic explorations, and well, not much has changed since then. There is still only one software program for Macintosh that I am aware of that allows users to uncompress the imagery locked away in the proprietary file format, GraphicConverter X for PowerPC-Macs.

Worse, I am having difficulty extracting the imagery that I want to use! The screen grab above shows the selection screen that pops up after I open the Mr. SID file containing the 2008 Washington, DC orthophotography. At first I was really excited that I could quickly and easily draw a box around the portion of the city I wanted to extract. However, after testing it out, I found that there is some latent bug in either the program or the file.

After I draw a box around the area I wish to extract, Graphic Converter spends a few moments decompressing the portion of the file, then it opens up the imagery. There is just one catch: the box I draw does not correspond to the imagery that opens up! For example, if I draw a box around the White House, a few moments later I am looking at imagery from Woodley Park neighborhood. After experimenting for about an hour, I discovered that the imagery is being extracted from somewhere northwest of where I am selecting. This is frustrating to say the least! Instead of quickly and easily obtaining the exact imagery that I want, I now have to do a series of trial & error selections in order to obtain exactly what I am looking for.

Moreover, due the level of compression used in Mr. SID, the uncompressed imagery contains small artifacts that diminish the overall quality of the original aerial orthophotography. To visualize this, imagine for a second that you decided to save a photograph using JPEG compression, but instead of selecting a high number (less compression) you select a very low number (high compression). When you look at the file that you saved, you can see little bits of digital static in the image. These artifacts are the result of high levels of digital compression in the Mr. SID file (80 to 1) and while its not excessive, it is present. I prefer uncompressed TIFFs because they generally look better.

The only way I’ve figure out how to reduce this annoyance is to actually reduce the size of the source aerial photography and in doing so, I’m reducing the overall spatial resolution of the original aerial photography. Released at approximately 15 centimeters per pixel, the imagery is so sharp that you can see people walking on the ground and be able to identify types of cars, but any reduction in size results in less precision and detail.

Nonetheless, I am very excited to start making more maps of Washignton, DC using the 2008 imagery! I look forward to exploring the nuances in development that have taken place over the years. I am also very appreciative of the DC GIS Program for providing me the new imagery free of charge. Thank You!

Then & Now Birds-Eye Views of the Westminster Neighborhood in Washington, DC [1884 & 2005]
|| 4/14/2008 || 12:42 pm || Comments Off on Then & Now Birds-Eye Views of the Westminster Neighborhood in Washington, DC [1884 & 2005] || ||

Detail the bicycle track before Westminster Street was created
from Adolph Sachse’s birds-eye view of the nation’s capital, 1884

Due to file format issues, only recently have I been able to open most of the maps available in the Library of Congress’ American Memory Collection. Last night I found an interesting birds-eye view map of Washington, DC by Adolph Sachse that was published in 1884. Its a massive map that appears to be composed of six separate sheets and contains a listing of many of the businesses in Washington City as well as locations of various public & government buildings. In many ways the map acts like a geovisual address book (the phone had not been invented yet) because, at a glance, one can easily find services offered by local merchants. Judging by the branding in the upper right hand corner of the original map, it appears that the map was sponsored by the Baltimore & Ohio Railroad Company, a major railroad company of the day.

According to my neighborhood’s official history, Westminster Street did not exist in 1884 and the birds-eye view above supports this claim. While not labeled in the image above, Parcel 362, as it was known on the original DC maps, was called also called “the old circus ground” and Athletic Park. It had a 150-foot long grand stand along T Street, which was built in 1883 (building permit number 1047) in preparation for the fifth national convention of the League of American Wheelmen, a national organization of bicyclists. The first American bicyclist to ever ride 100 miles on an outdoor track did it on that track in 1884. As someone who uses a bicycle as their primary means of urban transportation, I can only smile knowing that 121 years ago my residence was an outdoor bicycle race track. However, I laugh because I traveled with an exgirlfriend’s family circus when I was younger!

Below is a birds-eye view of the Westminster Neighborhood published by Microsoft, with imagery of Pictometry International. It features imagery that was taken in 2005 and when compared, you can see how much the area has changed in the last 121 years. The Athetic Park is gone and in it’s place are dozens of rowhouses that were built shortly after the map above was published. A unique and historically aware addition to the neighborhood is something you can see below in the playground on Westminster Street. No, it’s not because that is where I had my exhibit “North, South, East, Westminster“. Rather, if you look closely, you can see a small race track! A scaled reminder of what once was.

Detail of the Westminster Neighborhood by Microsoft, with imagery of Pictometry International

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Getting to know Mr. SID
|| 1/7/2008 || 3:13 pm || Comments Off on Getting to know Mr. SID || ||

Screen grab from the Library of Congress which DOES NOT list Graphic Converter as an option…. yet?

For the last few years I’ve found the file format Mr. SID to be the bane of my cartographic explorations. When I’d see a map available in the MultiResolution Seamless Image Database format, it meant I’d have to keep looking for other maps. Conversion of the Mr.SID format on a Macintosh had kept the maps locked away in an obscure file format; smiting me.

In my opinion, one of the worst decisions that the Library of Congress made was the choice to use the Mr.SID file format for their on-line maps. First off, its a proprietary compression algorithm patented by a company that is motivated by profit, not by the intent of furthering academic research. This means that any software maker originally had to get a license (pay) to use it. This resulted in only a few programs being written that can convert the file type. Worse is that there are even fewer Macintosh-based programs that can convert these files. The patent owner’s website offers only one Macintosh product and does not allow the rendering of the map at it’s full size. As in, I could only export sections of the original map, which makes the reader useless. Secondly, the file type is in itself “an American Memory,” because its not widely used anymore. It made sense to use it originally- it saved server space because of the high compression algorithm, but now server space is relatively cheap. Today only people who use high-end GIS software use Mr.SID formated imagery, and since most of this software only exists on PCs, there has been little cross platform support. Lastly, for any maps to be used by an image editing program, the map must first be converted out of the Mr.SID format and converted into another filetype (.jpg, tiff, etc.). This means that for every map that is available on the Library of Congress website, I have to spend 15 minutes converting it to a useful format.

Over the weekend I discovered that there is *one* program for Macintosh that can convert this file type: Graphic Converter. I also discovered that the newsest version (the Universal Binary, which I downloaded last summer) did not handle Mr.SID. Instead, I had to download an obsolete version (Graphic Converter for PowerPC) to convert this arcane format! So for the last 7 months I had been unable to convert any Mr.SID formatted map, but now I can, and I’m very excited about the new possibilities this opens up (literally hundreds of maps are now within virtual reach! The Library is only a few blocks away, but the digitalization is just as important.).

I sincerely hope the Library of Congress updates the page above to list Graphic Converter as one of the programs that can convert Mr.SID formatted maps. This software program is already listed for use with other media on the same Library of Congress webpage. Also of note, is that Graphic Converter can also convert JPEG2000 encoded maps.

The U.S. Capitol is Off-Limits to the Public: An Exploration of Censorship’s Perimeter
|| 3/25/2007 || 9:46 am || Comments Off on The U.S. Capitol is Off-Limits to the Public: An Exploration of Censorship’s Perimeter || ||

click image above to view my latest installment to the Lost Series

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Nikolas Schiller is a second-class American citizen living in America's last colony, Washington, DC. This blog is my on-line repository of what I have created or found on-line since May of 2004. If you have any questions or comments, please contact: