North River Geographic Systems Inc

Spatial Problem Solving

postgis

Fishbones for the TN NG911 Address Server

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It’s been a bit since I’ve talked about the TN address server. I’ve been slowly adding more functionality to it and some of that functionality has been more difficult than others.

If you’ve played in the address space any length of time you’ve heard of fishbones – and that is simply drawing a line from the address point to it’s “spot on the street”. Granted if you’ve ever done an addressing project from scratch (I had the joy to do that a few years ago in the Caribbean) it makes a lot of sense. You can quickly see problems where lines cross over other lines or where addresses have no lines at all.  Please read up here if you are so inclined.

There are probably multiple ways to do this  but I’ve gotten fishboning (if that’s a word) running in the TN NG911 Address Server. In PostGIS with less than 25 lines of SQL (and I’m quite proud of myself – 5 years ago I sucked at SQL. I still suck at it – but way less).  While it’s not quite ready for prime time it’s close – I’m just trying to figure out what I can pull out of this that makes the County’s job easier in the addressing realm. I’d love to move it to python at some point – and it’s probably doable (well I know it is – it’s just doing it).

Three things happen:

  1. I join the address point to the closest road using ST_LineLocatePoint
  2. Does the closest point fit the address range on the street (double bonus I also check left and right).
  3. Finish it up with ST_Makeline to join the spot closest to the street to the address point.

Which quickly shows something is wrong here:

Bonus for this one as is it’s not incredibly obvious what the problem is at first glance….UNTIL you see you have an addressing issue where you have 2, 3, and 4 on the same side of the street.

Hurrah for misspelled street names by leaving a W off

Anyway – there will be more announcements coming like this “running in the cloud” and other things. I’d like to get the fishbones running once a night or realistically run the one for the new address. Why not both probably. Anyway – pretty nice for an ArcView/FGDB Replacement.

The Seventh day of XYMas…PostGIS

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You knew this was coming….which I should have put this in the SQL post but I really felt like it needed it’s own short article.

I was introduced to PostGIS about 6 years ago. It took me about a year to wrap my head around it. When I started using it my first inclination was “Well this isn’t much different than SDE” except I had never used SDE for anything more than data storage. Suddenly I could use SQL and muck around in the data and do things.

I enjoy postgis – I still suck at it. I sit and struggle with the simpler things (In my opinion) but it’s the most satisfying tool I use daily.

If you went back to my second day of XYMas where I said ‘Learn GDAL’ and I’m going to somewhat contradict myself and go ‘Learn Postgis’ and at the very least learn Spatial SQL. Earlier I was talking to someone who was just starting out her career in conservation and her question was “I want to learn more about GIS so what do I need to do?”. She has a wide array of tools at her command from the current offerings from ESRI to QGIS. My response was “Let’s load all your data into PostGIS/PostgreSQL and you start working with it” (that’s the one tool we don’t have loaded). Which then lead to more of a discussion on why I thought this was important. I know what will happen:

  1. She will be slow to get started
  2. There will be one day where she’s alone in the office and the tech bug will hit and she will start working her way into PostGIS
  3. Suddenly you realize you’ve got a whole new world of ways to look at your data.

Anyway – yeah I know I’ve not dove into anything practical – but I actually have no idea how to do anything practical in the short space these articles take up. All I can say is learn:

 

 

 

The Fifth Day of XYMas…..My Workstation

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What? Hardware? You’ve only been complaining about Python for 3 out of the 4 articles….

So yeah I decided last night to talk about my computer…or at least my history of “computing” and how I ended up with this workstation. When young Randy walked out of college I’m not entirely sure that he had a computer.  It wasn’t until something like 1998 where I made my first purchase of a large unwieldy desktop (Gateway). Most of my computing needs were handled at work (Federal Gov’t) where we had this mix of Sun Sparc stations, Intergraph Hardware, and some HP workstations.

When we made the move from ESRI Software on Unix machines to Windows machines I suddenly had to care about hardware and all the parts inside of a computer because the IT Department didn’t care. So we’d sit down and go “well we think we need this so lets double it” and we had some very very expensive computers back in the late 90s to early 2000s. How expensive? I can’t put my fingers on any proof but at one point we purchased a Dell Workstation that cost about $14,000 dollars. I think that was right about 2001 or 2002. We had a Silicon Graphics Workstation that I’m 100% sure cost something like $35000 in 1999 dollars.

hp workstation
I didn’t get rid of it. Vintage Dell running Windows XP from 2006

Flash forward to “Randy owning a small business” and what did I do? My first purchase was a Dell mobile workstation ($3000 pictured above). Next was a Dell lower end workstation that was about $1500. One day for fun I bought a cheap HP Laptop in late 2012. I think it was 14inch and it had a 100 GB hard drive and a whole 4GB of RAM for $350. I loaded Linux on it and started playing around in my spare time with it and trying to see what could I do GIS wise. Over time the answer was “I can actually do quite a bit in 2013 with this laptop”.  Sometime that same year I started my move into a mixed environment of ESRI/FOSS4G. Sometime late in 2013 I decided to move my main workstation (Desktop) over to linux and run windows 7 in a virtual machine. That led to more experimentation.

What did I learn from all of this? FOSS4G runs light on the hardware end. I can work with cheaper equipment – not that I like or advise doing it but I can if I have to. I decided this year to go more high end than I have in the past so I bought a System76 Laptop.

What does this get me? Well – I’m looking at at least 4 to 6 years of service. I carry it out with me to clients. I might carry it into the field. I went canoeing with it once (no it’s not water proof but I didn’t feel like leaving it in the car). 32 GB of ram is a bit much – but I wanted as much as I could afford for longevity purposes. I went slim on hard drive space because more of my life is going “in the cloud” so to speak.

I’ve got another laptop with 16gb of Ram and it’s very capable – I just like the system76 one better. It’s a lenovo business class machine and it’s fine. I’ve done one thing with it and that was stick a SSd drive in it to speed it up – other than that it’s stock and boring.

What do I do when I get my laptop?

I also run whatever is current from Ubuntu. Yes – Current. I don’t do Long Term Releases except on servers and one desktop machine. Although I’m currently using Pop-OS and enjoying it (it’s based off Ubuntu).

…and I do more things – but this is a good first whack at a workstation. My assumption is when I go to a clients I have no internet. I can’t tether to my phone is my next assumption because cell service won’t be available. It’s pretty much me and what I take with me (so I take all the software). No joke – I went to a client’s location in NW Tennessee and had no phone service for 4 days (Thanks Sprint) and at least one day of 0 internet. I was at the mercy of the Hotel and the Client for internet most days and that wasn’t a given. I was left with my brain to get work done – no “hive mind” for me that day.

laptop
Stickers are the Prison Tattoo of the 21st Century

What do I tell my clients? Get what you can afford. Maybe go just a bit better than you think but this isn’t a long conversation of gaming computers vs workstation vs nvidia vs radeon vs etc etc. It’s actually nice to look at a laptop and go “If you don’t blow up you’re good for 4-6 years”.  I’m all for equipment with warranties and not running hardware to death – I just don’t care a lot about hardware anymore. My current fantasy is linux on a chromebook to see what I can do with some lower end computing power where my battery runs a good part of the day. Can I have a decent workstation with the cheapest of cheapest hardware? I think so.

“Yeah but what if I run Windows?” That’s 200% fine and there is nothing wrong with it (and some days I wonder if it would make my life easier). You may need something a bit better than a business class machine but you don’t need a gaming computer to run your FOSS4G. If you’re running ESRI Software there is enough info out there on what you need – but whatever you get your FOSS4G will work just fine on it. I say that and don’t be completely ignorant about your hardware – but you don’t need to worry as much as you think you need to worry. I’m big on not worrying these days.

So anyway – Hardware. Something I don’t worry a ton about BUT it is important BUT it’s less important than having good clean data.

 

TN 911 Server Updates

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The TN NG911 server got an upgrade this month with some quality assurance checks. After working with Henry County for the last bit we’re into more “what if” scenarios.

  • What if we ran checks for misspelled addresses or improperly labeled addresses?
  • What if we started filling out the fields we weren’t filling with out with our ArcGIS/Geodatabase setup?

Working with Chad Howard (911 GIS Guru for Henry County TN) we’ve started playing with data problems. One thing I learned is that the amount of quality assurance checks at the county level are lacking – not because anyone didn’t want to do it it’s just hard working with a basic arcgis license to do anything significant. That’s where postgis comes into play. I’ve got a total of three checks on the addresses planned with two implemented as of right now.

What if you accidentally add two address points with the same geometry? A red circle appears in one of the layers in your database (and in your QGIS session) alerting you to the mistake. What if you accidentally misspell an address street name and that doesn’t match a street? A blue circle appears. If you look at the example it looks like someone can’t spell. Actually the old setup was adding spaces to names. So instead of “Main” you had “Main “. That’s an easy enough fix we can do in a bulk edit.

I expect these next set of checks to slowly become irrelevant over the next bit as the client takes full advantage of QGIS’s forms for data entry. Once again we’re hitting spaces as opposed to nulls in the data in 80% of the cases. We should only have 4 pre-directionals – well at most 8 –  but for this county they only have 4.

We can bulk edit the spaces away in the database. It’s nice to have this table sitting in the qaqc schema just to check occasionally but I do expect that to drift off in significance the more we use Fulcrum and QGIS’s Forms for data input. These checks check everything from street types, names, to directionals. Like I said – over time these start drifting off in significance but it’s nice for now.

Anyway – more quality checks are planned but we’re over he first hurdle to making this even more useful and easy.

TN NG-911 Server

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Last year I had the chance to work with Henry County TN’s 911 group on a software migration project. I moved the organization off a basic commercial GIS product to an open source enterprise server. Overall it was a great project with a defined end goal and a lot of flexibility in making it happen.

Once the project ended I never stopped working on the database and the tools. Over the last few months I’ve had the chance to turn the database into something that is 100% compliant with the State of TN’s NG911 System. I present the TN NG911 Server.

What does it look like?

The workflow is simple. Field Personnel go out and collect data using menus set up in Fulcrum.

Data is stored in PostGIS/PostgreSQL and edited with custom menus in QGIS. The database is served out through Geoserver as an OGC service.

Data is exported from the server at night to the the states ESRI database.

The bonuses to this approach:

  • 100% TN NG911 Compliant
  • Cloud Deployment Or Onsite Deployment
  • Local TN Support for your organization
  • Can Interface with Computer Aided Dispatch Systems through managed Exports.
  • Quality Checks on your attributes
  • Topology checks for your data
  • Unlimited Desktop Deployments for everyone
  • Can work with TN’s LIDAR Data and TN’s Imagery Services.
  • Handles more than just the 3 data layers the state needs for NG911

Granted it’s not 100% open source as Fulcrum is a commercial product. Fulcrum will need to be purchased but it’s only a fraction of what you could be spending on software and it has more uses than just address collection.

The TN NG911 Server has a solid deployment that’s been in production a year. If you’re interested in integrating Open Source GIS into your 911 system you should at least look at this approach. Everyone needs good clean data.

Future plans have a plugin and more quality checks on the data. For Version 1 though this is very solid and very functional.

What about the NENA Standard? The TN Standard is not NENA Compliant! Well – stay tuned for more news.

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