The Joys of Geocoding

In my last post, I was asked what the accuracy of the locations in our generated Google Earth files are. Before I divulge that information, I’d like to explain some of the challenges of getting accurately geocoded data. (I’ll get on my soapbox and complain about the state of NWMLS data in my next post).

GPS Signal WiggleNow, in partial defense of realtors and the MLS, it is unrealistic to expect perfect data. For example, consumer-level GPS receivers aren’t always as accurate as one might think. This weekend I loaded up Microsoft Streets & Tips 2006 on my desktop computer, hooked up my GPS receiver, turned on GPS tracking , created a GPS trail, and walked away for an hour. An hour later, my map had a line drawing that resembled the type my 3 year old son likes to create. So even if a realtor was to use a GPS receiver, to get a latitude & longitude reading, it’s entirely possible that the measurement would be off by a house or two (or four).

Another problem, is that most digital maps are created with data sold by companies like TeleAtlas or NavTeq. The companies compile their data by driving around previously unknown streets & neighborhoods, with computers & GPS receivers (kinda like how that annoying guy in the Verizon ads, test their network). I should note that in-vehicle navigation systems are more accurate than GPS receivers alone, because the vehicle’s navigation system can also use the vehicle’s steeling wheel position and the speedometer to determine what your location is.

Unfortunately, by the time the Microsoft’s, Yahoo’s and Google’s of the world get their hands on the data, it is at least 3-6 months out of date (and probably closer to 12-18 months out of date by the time it gets on the web or published on a CD). This is a problem because about 25% of the properties in the NWMLS are new construction (where new construction is defined as a property that was built in 2005 or later). Since new construction is often located near new roads, the giants of digital mapping may be unable to help and are always in a position of playing catch up.

Then when the companies convert the raw data into digital maps, they end up using multiple sources of data, and interpolating it into one set of data they are going to use for a map. However, the data sources don’t always agree on where a point of interest is.

For example, Google Earth thinks the top of the Seattle Space Needle is at 47.620367° north latitude & 122.349005° west longitude. Meanwhile, Microsoft’s Virtual Earth, seems to think it’s located at 47.620336° north latitude & 122.348515° west longitude. Now, a few ten thousand-enths of a degree means the difference between the tip of the needle & one of the air conditioning units on the roof (a few yards). But if they can’t agree on where the top of the Space Needle is, it’s likely they aren’t going to agree on where 742 Evergreen Terrace is either. However, a few yards of error is better than a few miles of error (which is what can happen when I use raw NWMLS data)

Because of this, I have to geocode every single property in the database because I don’t trust the NWMLS data. So I to call Yahoo! Maps Web Services – Geocoding API to get a latitude & longitude for everything. Although Yahoo is far from perfect, at least it’s free and try’s harder than the MLS. So without further delay, here is the current geocoding precision of the points on our generated maps.

Geocoding Precision No. of properties Percentage
address 16341 80.20
street 1975 9.69
zip+4 43 .21
zip+2 343 1.68
zip 1644 8.07
city 25 .12
state 5 .02

In closing, I’d like to ask real estate professionals to be as complete and as accurate as possible when submitting listing data to their local MLS. I’d also like to state even if the MLS was accurate, it’s unrealistic to expect prefect geo-coding from imperfect data. If digital mapping companies and GPS technology can’t get it exactly right, a house or two off, is probably as accurate as you can realistically hope for given the current state of the art.

Robbie
Caffeinated Software

John Cook Interviews Redfin CEO: Redfin is "crazy-good"

Dustin pointed out that John Cook over at the Seattle PI just published an interesting interview of Redfin’s CEO, Glenn Kelman (Direct link to the mp3).

Before I jump in, I should point out that I run ShackPrices.com, a site that is faintly a Redfin competitor. That said, that both Redfin and ShackPrices are much more worried about our customers and competitors with lots of money than we are about each other. I’ll try my best to stay unbiased.

Up to this point, Dustin has been under the impression that Redfin is very insular (He’s even gone so far as to say “arrogant”). I get the impression that Redfin has some interesting technologies, but they are still looking for their path; Glenn is doing a big marketing push on a site that has only had cosmetic changes (to real estate buyers) in the last year. Throughout the interview he raves about his site. I think he says exciting ten times and “crazy-happy” or “crazy-love” at least three times. If you check Redfin.com, their news bar clearly shows that they’re on a marketing push (it also shows they still don’t have an interface person who can tell them to use that valuable space more effectively).

Glenn then talks about how addictive (crazy-addictive?) he finds the Redfin site. Personally, I get much more excited by the technologies behind PropSmart and Trulia. Those sites seem to have added to cool aerial photos with some real focus on the user interface. Redfin gives you great information about individual houses and even shows you the lot line, but it doesn’t give you any medium- to big-picture information. Neighborhood and city pricing information is worth much more than a single house’s historical sales (and this is coming from the dude who has only historical sales on his site).

I think it is interesting how an interview can really bring out the best and worst in somebody by just letting them talk. More articulately than anyone else I’ve heard from Redfin, Glenn describes the company’s lack of focus. For instance, he talks about how every state is different and national websites can’t accommodate that. Next, he talks about how he’s going to expand down the West Coast and all over the country. He talks about how cool the site is and how technology is changing, but gives digital photos of houses as an example of this trend (that was cool 5 years ago!). Even in vegan-city Seattle, I want to know where’s the meat to go with this fluff? When asked what’s driving traffic to Redfin, Glenn says “because it’s an awesome site.” I think I would have gone with “aerial imagery, property outlines and past sales data.” And if they don’t add to that list, they risk becoming just-another-mapping-site.

A while back, Anna wrote this article that showed how Redfin wants it both ways with real estate agents… and it is interesting that while Glenn is new to the staff (he started in September), he inarticulately describes this same conundrum that Redfin faces.

He says,

we’re not trying to serve the real estate agents… sell people out to real estate agents… what we’re trying to do instead is serve the consumer directly…

But when pressed by John about how Redfin makes money, he says

How do we make money now? People sign up for a real estate agent… The real estate agent and Redfin share the fruits of that.

Which essentially means “by selling customer names to agents.” I’ll give him credit – I hate the housevalues model and find it to be really sleazy and maybe there really is something to be said for waiting until someone requests an agent. However, they are not, as he says, “trying to do something totally different.” Redfin is just leaving more money on the table and, possibly generating higher-quality leads. I’m going to read into this, though, and say that they don’t plan on working with agents for long – note his question to himself “How do we make money now?

Dustin says “it is not hard to read between the lines that he’d really like to squeeze those agents out of the business if only it wasn’t for those “great” relationships he’s built up with a few of them.” I agree. Late in the interview he emphasizes how he wants to balance the business model:

… balancing our business model. We’ve got real estate agents that are partners, that we still value enormously, but we want to make sure we keep the focus on the home buyer and seller who is the customer.”

Word to agents: now that we have funding, you are not a priority.

This is my favorite part:

If you walked into Redfin, all you would see are engineers and a customer support person.

-Galen
ShackPrices.com

7 Reasons for Real Estate Agents to Blog

A recent conversation on Tribe got me thinking about my experiences with being a real estate blogger. Here are my seven reasons real estate agents should consider blogging:

  1. Fun. I really enjoy the many conversations that I’ve had with real estate professionals from all over the world that would never had taken place had I not started this blog!
  2. Expertise. By simply writing about real estate and your local community in a public forum (like this!) you become an expert. Anna gets emails and calls from people on a regular basis asking for her opinion on real estate issues. I’m a transportation engineer, but even my opinion on real estate issues holds some weight! For example, someone from my wife’s corporate office recently called to get advice on how to better use technology in real estate.
  3. Trust. A client recently told my wife that he completely trusted her advice because of the honesty in her writing! That’s darn near impossible to get with a regular website.
  4. Knowledge. I follow local news, national news, local blogs, real estate blogs, tech blogs, etc, because I feel a responsibility to my readers. Maybe you won’t feel that internal pressure, but it definitely drives me to ensure that I’m up-to-date on real estate news.
  5. Ranking. Because of all the unique content, we get hits on all kinds of unusual real estate searches. In addition, because we’ve gotten some links from some high-ranked websites (mostly other blogs), her site ranks really well when compared to most real estate sites. Additionally, on typical real estate searches like “Seattle real estate”, we’re ranked very high (#7 on Google) for such a new site and I know that we’re beating out sites that are spending $1000s a year on marketing their site.
  6. Cost. Compared to most marketing techniques that agents are using, blogging might as well be free. I pay $100 a year to host this site. That’s it! The cost of blogging is measured in time, not money!
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  8. Potential. Rain City Guide is not even 10 months old yet. Give us two or three years of blogging, and we’ll easily be the most popular real estate site in Seattle. Ideally, the site will continue to grow as the web technologies evolve and more perspectives are added. I’d love to do more podcasting and videoblogging. I’d love to have someone document the building or remodeling of their home. I’d love to have some more real estate agents blogging about their local areas (Seattle, Bellevue, Redmond, etc. neighborhoods). I’d love to have someone take on some more analytical issues (Tom?). There are so many interesting ways that Rain City Guide can evolve that I feel like we’re only touching the surface of it’s potential.

When I look into my crystal ball to see the future of real estate blogging, I see one or two real estate blogs in each major city that have really captured the local market by having a group of prolific real estate professionals (agents, brokers, lawyers, etc) writing about local issues. I see people turning to these blogs to get unique and personal perspectives on issues like moving, building, buying and listing. I don’t think you’ll be surprised to hear that that is where I plan on taking Rain City Guide!