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How to get building footprint drawings quickly
March 30, 2011 5:39 AM   Subscribe

What are the best options for generating dimensioned footprint drawings of existing single family homes in Central Texas?

I have a customer in the construction industry who needs 2d drawings or sketches of private home footprints with reasonably correct dimensions (say with a +-10% margin of error).

The sketches should be in an electronic file format that can be redimensioned (allowing him to correct incorrect dimensions) and that allows him to add very limited elements along the outer perimeter of a home.

I've looked at using Google's SketchUp along with Google Earth, but I'm not sure this is a good way to do it - I haven't had much luck getting high enough quality images from Google Earth to work with.

I've also looked at services such as EagleView, but their service is specifically for roofers. Their reports contain a good deal of information that my customer doesn't need, and they're pretty expensive (up to $115 for a report on a large structure with same day delivery).

Some jurisdictions offer dimensioned sketches online, already, but Travis and the surrounding Texas counties don't. Travis county uses EagleView for tax assessment purposes, but it doesn't seem that they make this data easily accessible to the public.

In the best-case scenario, my customer would be able to quickly generate or order a sketch of a house before he visits the homeowner - quickly means with an hour of in-house work, or with one day of turnaround time from an external service, max.

Another solution that might be acceptable would be involve measuring (lasers, maybe?) the actual structure and turn the measurements into a drawing, quickly (on the scene, if possible).

My customer is willing to pay for a good solution that he could use in-house (Google SketchUp Pro + Google Earth Pro would be in his price range, for instance). He'd also be willing to pay around $10 per drawing to a company or individual who provides this kind of service.
posted by syzygy to Technology (12 answers total) 1 user marked this as a favorite
 
Tax records, usually held by the local tax assessor, almost always have a roughly dimensioned building footprint along with lot dimensions. That combined with Sketchup Pro (with Layout) might do the trick.
posted by skyscraper at 6:29 AM on March 30, 2011


@skyscraper: Travis and the surrounding counties seem to be woefully behind the times on this one. I think they have these records, but they don't seem to make them available online. I've seen lot or plat maps at the official Tax Appraiser websites, but I haven't been able to find any drawings of structures on the addresses I've searched for, so far.
posted by syzygy at 6:45 AM on March 30, 2011


Maybe talk to the City Engineer's office. They're likely to be responsible for keeping track of sewer lines, electrical lines, driveway placement, home inspections, etc., so they may be able to provide more data along those lines.

And have you asked the GIS people where they'd suggest you look? GIS may not have the physical data, but they might know who to talk to.
posted by AzraelBrown at 7:21 AM on March 30, 2011


I believe floor plans were available for a while but it appears that now photos, sketches, and floor plans of residences aren't available publicly on the internet in Texas by law.

TaxNetUSA says that these records are viewable if you pay for an account. I haven't used them for anything other than their publicly-available searches & can't recommend for or against.
posted by magicbus at 7:43 AM on March 30, 2011


Many cities don't keep or make public interior house plans. I am pretty sure that my city has no record of the interior layout of my house, for example.

I would have thought that CAD would be an easy, but not cheap, way to do the drawings.
posted by Forktine at 7:50 AM on March 30, 2011


who needs 2d drawings or sketches of private home footprints

By 'footprints' this sounds like it would not involve interior rooms, which is a whole different story.

So... for a low budget, your best bet is to just use Google Earth or Bing Maps to get the maximum quality zoomed-in image of the house. Take a snapshot and import this into Adobe Illustrator. Rotate the image so the house is square with the page. Lock down the layer and create a work layer. Now use the line tools to draw the footprint. Now go into Google Earth and use the measuring tool to get dimensions for the walls, which will get you 10 to 15% accuracy on a residential house unless the images being served up are those crappy USGS images (which is the case in some rural areas). You also have to be aware some of the images are not taken from the zenith, so you have to visualize the shape of the house and make sure you're selecting the correct points to measure, and account for roof overhang -- you can use Google Street images to make adjustments. Place the dimensions along your walls in Illustrator using point text. Turn off the image layer, touch up, and deliver to the customer. They can use Illustrator to make corrections (and can re-enable the background image if they want).

Illustrator is not cheap, but an investment is going to be required somewhere and for something like this, it uses a standardized format and is going to do the job flawlessly. I used to do this kind of work several years ago and it was ideal for simple jobs. I could probably do a professional, dimensioned footprint in about 10 minutes this way. CAD software is doable, but would be overkill IMHO and it will either be expensive or will make a chore out of tracing work and annotations.
posted by crapmatic at 8:20 AM on March 30, 2011


magicbus: Thanks for the background information. I was wondering why some states make this information public, but Texas doesn't. I figured they were just behind the times, and that the sketches we need would be forthcoming, eventually. We're going to purchase a few credits at TaxNetUSA.com and see how the sketches look - awesome info!

crapmatic: You're correct - we don't need floorplans, just perimiter dimensions. I've played around with creating sketches from Google Earth, but the zenith problem is sometimes tough. Your workflow sounds good, though. I've found that historical images in Google Earth are often better quality than the latest images, so if TaxNetUSA doesn't work for us, we'll give your workflow a shot. Thanks for the tips!
posted by syzygy at 8:33 AM on March 30, 2011


Please excuse my typos and poor wording - I'm severely jetlagged at the moment.
posted by syzygy at 8:47 AM on March 30, 2011


So my (Northern California) city's GIS department has ESRI shapefiles of approximate building outlines. Depending on how accurate your data needs to be, you might be able to mashup those with zoning data from the city, or parcel data from the county, to get basic lot drawing info. Using GIS data is an education, but QGIS is a free viewer that lets you deal with shapefiles fairly (just remember that you have a projection for the layer and a projection for the project, don't try to understand that yet, you'll thank me later). Or your county/city's department can probably point you to an ESRI product to explore their data (if they don't just have it online). Of course that's probably good to a foot or two at best.

My county assessor's office (California) doesn't have computerized records, but they do have building outer dimensions. What they don't have is lot locations for those buildings.
posted by straw at 8:59 AM on March 30, 2011 [1 favorite]


What straw says about asking the planning department for the shapefile of building footprints. Not all counties/cities have these available, and some charge pretty steep prices, and worst of all these shapefiles can have pretty significant errors, but it will take care of 90% of your work.
posted by Forktine at 9:26 PM on March 30, 2011


Thanks everybody. I've got 3 good possibilities here, so I feel like this is something we can tackle, one way or another. I appreciate the informed advice!
posted by syzygy at 4:03 AM on April 4, 2011


Here's another if its not too late. Take advantage of crowd sourcing. Check out openstreetmap.org. it let's you create free maps. You can add building footprints by tracing high quality aerial maps. Then you can export them in various formats. You might be able to find some mappers who could help you create the buildings.
posted by nmixter at 1:55 AM on May 13, 2011


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