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article imageSatellite imagery makes it hard to hide from the tax collectors

By Karen Graham     May 27, 2018 in Technology
If you thought you could conveniently forget to put your home addition or swimming pool on next year's tax return, you may be surprised to learn the Tax Guy in the Sky will see your new addition even if it’s hidden from the street.
Yes, technology is really great, and satellite imaging is a remarkable resource. Satellites give us critical information that has many applications - like the environment, forestry, landscape, geology, cartography, regional planning, education, intelligence and warfare and many other fields.
But what about using high-resolution satellite imagery to assess the completeness of existing tax maps as an aid in ensuring tax rolls are complete and land valuations are current? Some of us older folks might remember that years ago, property taxes were dependent on tax assessors who actually had to physically look at a piece of property.
At 10 meters  it s easy to see roads and water features. Now look at the next image below.
At 10 meters, it's easy to see roads and water features. Now look at the next image below.
World View
Not only that, but taxation was dependent on whether a taxpayer was honest in asking for a building permit to add an addition to their home or a garage on their property. Then, it was assumed the same taxpayer would report the addition when filing their tax return.
And basically, the system does work, because after all, most of us are honest and hard-working people, wherever we live. However, we can all agree that today's property taxes are "sky high," and in some cities, they are astronomical.
Using satellite imagery to update tax maps
Not to alarm anyone, but a new study entitled "Using satellite imagery to revolutionize creation of tax maps and local revenue collection," published on May 25 by the World Bank Group suggests taxes may soon be literally "stratospheric," or even higher.
At 30-60 centimeters  you can easily discern key features such as manholes and mailboxes.
At 30-60 centimeters, you can easily discern key features such as manholes and mailboxes.
World View
Basically, the paper explains how high-resolution satellite imagery makes it possible to assess the completeness of existing tax maps by estimating built-up areas based on building heights and footprints.
The Financial Post's William Watson writes, "Big cities in poor countries badly need infrastructure to launch economic growth and keep it on a sustainable glide path. If the benefits people get from municipal spending are proportional to the value of their property — not a bad working assumption — then property taxation is a way of financing city spending that roughly equates peoples’ taxes to their benefits."
But I would add the key point in this thinking is that poor or developing countries might have a hard time launching any kind of sustainable economic growth without investors because raising people's taxes would be like trying to get water out of a dried up hole.
SPOT 6 Early Image – Acquired during commissioning phase. Vancouver  British Columbia  Canada.
SPOT 6 Early Image – Acquired during commissioning phase. Vancouver, British Columbia, Canada.
SPOT 6 Satellite Image
Imaging satellites and their resolution
There are four types of resolution when discussing satellite imagery in remote sensing: spatial, spectral, temporal, and radiometric. Additionally, geometric resolution refers to the satellite sensor's ability to effectively image a portion of the Earth's surface in a single pixel.
A satellite's resolution also depends on several factors, including the instrument used and the altitude of the satellite's orbit. And satellite imagery is sometimes supplemented with aerial photography, which has higher resolution but is more expensive per square meter.
However, even with all this technology, because the land area of the Earth is so large — and satellite image resolution is so high — satellite databases are absolutely huge, and creating useful data from the raw images is time-consuming. For this reason, publicly available satellite image datasets are usually processed for visual or scientific commercial use by third parties.
Satellite image showing Northwest Passage.
Satellite image showing Northwest Passage.
NASA Images
This also means commercial satellite companies do not sell or place their satellite imagery in the public domain. In order to access their images, one must be licensed to use their imagery. Thus, the ability to legally make derivative products from commercial satellite imagery is minimized.
In order to come up with their study results, the World Bank researchers who wrote the paper used high-resolution imagery from the Pléiades satellite, which, according to its website, is available in “record time,” and then applied a “semi-global matching algorithm”
The RoadTracer map process in operation.
The RoadTracer map process in operation.
MIT’s Computer Science and Artificial Intelligence Laboratory
Rwanda was used for the study because it is the only African nation that has established a complete and fully digital legal cadaster (a comprehensive land record of real estate). While it is somewhat surprising that the data are not used for fiscal purposes, the registry reliably records prices for any transaction.
Together with data on building heights or the volume of built-up area generated from high-resolution satellite imagery, the research team was able to calculate a 1.0 percent tax on residential land and property. The study authors conclude in comparison of such a tax to actual and potential yields from the current system, this also makes it possible to estimate the likely effects of proposed exemptions, thus laying the foundation for better-informed policy.
An aerial view of the National Security Agency in Fort Meade  Maryland
An aerial view of the National Security Agency in Fort Meade, Maryland
Patrick Smith, GETTY IMAGES NORTH AMERICA/AFP/File
And while this may work well for a developing country, it does leave one to wonder how it would work in say, Los Angeles or New York City. Metropolitan areas have so many variables, not only in income levels, but in land usage — such as differences in residential and industrial areas.
Keep in mind that economists are already using night lighting to confirm — or in some cases — estimate Gross Domestic Product (GDP), using the well-established relationship between electricity and GDP. And we must not forget satellites are already used to estimate crop sizes. Adding an algorithm or two could also give us the value of a crop and the expected income, after taxes.
How does that old song go? - The times they are a-changing.
More about Satellite imagery, tax maps, tax revenues, building additions, Planning