Lidar

Class, GRASS, and LAS – LIDAR in TN Part 3

rjhale · Jul 6, 2017 ·

And now for Part 3.

So something exciting happened. If you’ve been keeping up with the TN GIS Data site you’ll notice a lot more data has been released in uncomfortably HUGE zip files. I downloaded two counties worth and have been exploring the data. In the meantime I started getting a few emails of “hey we’re getting data on a hard drive”. The cool thing with that is I received a tile from a county and it’s in LAS. If you read through some of my other rants I’ve been annoyed by the fact this is in zlas format. If you do some digging on zlas it’s more or less ESRI going “Hey we’ve made a format that only we use” and you have to unlock it to make it useful by anything else. We’ll – the counties are getting unlocked data. Victory.

BUT – there’s one more Problem. In all my examples I’ve been using GRASS. So I tried to pull the data in and nothing good happened. Actually – nothing happened. It was then I started learning about liblas and the LAS Library Versions. The short story is GRASS will read the 1.2 LAS Version. The data provided by the state is in 1.4. So you can’t automatically use GRASS to do anything with the data.

EXCEPT PDAL TO THE RESCUE! Probably the one thing I’m learning is I’m not short on tools to use with LIDAR. I’m up to: GRASS, PDAL, SAGA, and LASTOOLS. I will spare you all the information on how to get PDAL – read about it on the website. For those of you on Windows: if you have QGIS from the OSGEO Network Installer, you can download PDAL painlessly and be quite happy. As I’m running Linux on everything I grabbed a copy and compiled it and have it locally. I’m also quite happy with that.

So the one thing you need to know is this: pdal translate inputlasfile outputlasfile . Issue that command from the OSGEO window. Something wonderful happens – you get a LAS file v 1.2 you can run through GRASS.

You can do things like making a map of the intensity values:

Or a hillshade for posterity:

To get from an LAS file to anything above is about 10 minutes. Maybe 12 minutes. I’m running this on a laptop with a lot of RAM – but I could do this on a much lower end machine.

I’ve covered GRASS and LAS….Oh Class! Read your metadata. If you read Part 2 above you’ll notice there is a change in Classification with the new data:

Classification	Value
Unclassified	1
Bare Earth	2
Low Noise	6
Water	9
Ignored ground	10
Bridges	17
High Noise	18

…and there – I finished my horrific joke of LAS, GRASS, and Class. I’m not explaining it.

It’s happening. LAS files for TN are out and about. My first thought is what can I do with this….my second is what are you TN Citizens going to do with it. My first two requests have been:

How do we get Tree Height?
Can we see Archaeological sites?

So – my next goal is to process A LOT of LIDAR at night. I’m going to set up a process to fix the format (unfortunately the data on the States website is still zlas), fix the library version, and then process a lot of data. Overnight? During the day? Who knows.

Georgia URISA Luncheon – January 10th 2016

rjhale · Jan 5, 2017 ·

LIDAR is a hot topic in Georgia these days. So – for the January 2016 Luncheon more LIDAR.

“LIDAR Updates – Changes in the Technology and Coverage”
Speaker Name: Ernie Smith

Presentation Summary: Like all Technology LiDAR has become very dynamic with new sensors and available data. We will talk about the advancements and availability of Sensors, Standards, and Data sets. There are many changes in the technology and unless you are working with it everyday, it’s difficult to keep up with all of the advancements.

Standards are also changing due to the sensor technology advancement which means practices and applications for LiDAR are growing. Also drones are being used for data collection and there are some things to be aware of for that use of Technology. We will present a map that gives our best understanding of where LiDAR data exists in Georgia as well.

Location:
Henry County Water Authority (Engineering Building)
100 Westridge Industrial Boulevard
McDonough, GA 30253

Georgia URISA November Luncheon November 8th 2016

rjhale · Oct 25, 2016 ·

Speaker Name: Jimmy Nolan

Speaker Bio: Mr. Nolan began working with GIS in 1994 when he was the chief appraiser for Morgan County. In 1999 Jimmy went to work as the GIS specialist for the Georgia Department of Revenue. In 2001 he became the local government project manager for the Information Technology Services division of the Carl Vinson Institute of Government at the University of Georgia. Since joining ITOS he has been instrumental in helping develop GIS in approximately 50 counties and has worked with local officials in many more counties and cities to enhance data or provide advice and training. Jimmy is the Cadastral Coordinator for the state of Georgia and was on the Federal Geographic Data Committee technical working group that developed the parcel data content standards for the eastern 31 states. He is the immediate past chairman of the Georgia GIS coordinating committee and a former Ga. URISA board member. He has extensive knowledge of how Computer Assisted Mass Appraisal systems model property values and how the data used in these models is organized as well as how these systems integrate with GIS.

Presentation Summary: The presentation will cover:

Current initiatives
Upcoming LiDAR acquisition projects
Coordination between multiple agencies at all levels of government
The 3DEP grant application that the state has submitted.

Additional Information:

Join WebEx meeting
Meeting number (access code): 927 999 105
Meeting password: URISA

Join by phone
+1-855-282-6330 US TOLL FREE
+1-415-655-0003 US TOLL
Location:
Hexagon Geospatial
5051 Peachtree Corners Circle
Norcross, GA 30092 USA

Adventures in LIDAR and GRASS in Tennessee: Part 2

rjhale · Aug 31, 2016 ·

Sometimes it takes a while to follow up on a blog post. A while back I wrote more or less “I got me some LIDAR what can I do with it?”. Well…..

First I need to learn about LIDAR and at some point (probably during Part 3) names will be named. There have been several people in the FOSS4G world helping me move along and learn.

Second thing I needed to do was ask questions. I asked a lot. I learned:

TN has been participating in 3DEP. So this LIDAR Data (as well as several other products) are coming from that program.
I need to read metadata.

So when I left you on my original post I was importing LIDAR into GRASS and somewhat failing miserably. After reading the metadata the point data was classified as follows:
Class 1 = Unclassified. This class includes vegetation, buildings, noise etc.
Class 2 = Ground
Class 7= Noise
Class 8= Model Key Points
Class 9 = Water
Class 12=Overlap Points (high scan angles)
Class 13= Bridge Deck Points

So this gets a little bit easier. Using v.in.lidar I can now build a DEM and pull the values coded for bare earth straight in.

Hillshaded for posterity:

Once I started “playing” fun things started happening. I know this isn’t 100% right because I have more to learn. What if I import LIDAR data coded as vegetation and subtract that from the DEM. I have Vegetation height. With the Ortho image I can shove more knowledge toward my foresters. I also have some negative values I’m going to investigate.

You may be going “Well that’s great you’re sitting here doing crap anyone can do”. Possibly. For a small entity with limited budget you can whip out GRASS and start doing things. This was a 10 minute endeavor for one tile. I also generated slope and I’m working on building a solar radiance map of the area. Now I want to process the entire county for elevation. Can I? I will also dump this out to QGIS because I can.

The big kicker in all of this THIS IS FREE DATA. Well – except for the zlas problem. State of TN – take the lead and open the format for the users. Switch to las.

So what am I doing for Part 3:

Upgrading GRASS to 7.2 (I’m running 7.0.4)
Count LIDAR points on the ground – the metadata claims one point per meter.
Will someone give me the RAW data? I’m attending a conference where people of influence will be – I’m going to ask.
UAV?
Building Height with elevation above ground?

I have a lot to learn and I am by no means an expert. LIDAR started getting popular about the time I walked out of my federal job and I never have clients that go “We’ve got this data sitting around”. I’ve never had to deal with it but now that I have a source to work with there’s a lot I can do. I have a community of people that will answer questions when I have them. Never stop learning.

Anyway – Part 3 is coming and it won’t take months for me to get to it.

The week that was – The business that is

rjhale · Jul 31, 2016 ·

It was a crazy week.

I’m right at one year when I moved back to Chattanooga. I’m bad about anniversary dates – as in the small things will stick with me at times bigger than the big dates. Something will be bothering me and if I think long enough – there’s a small bookmark in my life I’m approaching. Anyway – one year ago I moved into this crazy neighborhood much to the dismay of my family. Change is good. Life is Change.

A year ago I decided I was going to make some much needed business changes – and that started and overall it’s been a pretty decent change. The changes made me a bit more hopeful for the future and I don’t feel like I’m in this strictly for the money – BUT – money did move up a few notches on the list thanks to a lot of advice.

Anyway – Monday started out with me learning more on PostGIS/PostgreSQL. A job with a client is going well – we just couldn’t get one thing to work. Figured it out. I took that victory to then decide to go talk at the North East Tennessee GIS Meeting. What was I going to talk about? This move out of ESRI for a utility client into QGIS/PostGIS/Fulcrum. So I started writing…

My presentations tend to take 2 forms: They are terrible or pretty decent. I’ve done terrible ones. I’ve done awesome ones. I’ve learned more from the bad ones than the good ones. I had 20 minutes so I made 10 slides. No graphics. Decided to do more demos than presentations. Which is awesome I think – as long as you have internet……

I dove back into Geohipster on Monday and got one interview done with Regina Obe – the fastest interview I’ve ever done by the way. That was a fun email exchange. Anyway – look for that on geohipster.com on Monday.

Things started getting weird on Wednesday – a new potential client popped up and they are neck deep in ESRI – server, mobile, etc. Which is fine – they need help so we started the discussion. With the changes in business my decision to either help them or not is easier – there are things I like doing and things I don’t. I’m in the middle of researching their problems. I can give them a yes or no and be happy with decision.

NetGIS meets in Kingsport TN – it’s a nice drive 90% of the time. The area is beautiful. I had decided to leave early and goof off. I didn’t leave early. The time for the meeting also bumped back just a hair. I made it though…..45 minutes before the meeting started and in I walked. I also spent the time in the car listening to Pandora. What do I listen to?

On the drive up I received word a GIS Peer had passed away. I knew Leonard Slote well enough to go have a beer with him and talk smack about software. He was out riding his bike and was hit by a careless driver. Probably dead at the scene but he was declared dead after they arrived at the hospital. Life is so short. I went canoeing on Wednesday and with one careless goof I dropped my paddle and just about tipped over in some unfriendly water. I served with Leonard on a GIS Conference Committee. Which also made me think about how many Boards and Committees I’m on now.

None. That’s how many. It’s incredibly nice. How can you be a guy who is contributing and shaping the Geo World if you aren’t on any boards? I think the Geo world is getting along quite well without me being anywhere in the mix. I left all the boards and obligations a while back. I do a few things for fun currently – but they are insignificant in the greater scheme of things. I might start integrating myself back in slowly. Maybe. I haven’t quite decided if it’s worth the effort.

Live Demo’s are awesome as long as you have internet. Which I didn’t have. Well…….Scrub the Fulcrum one because I didn’t plan for anything but a live demo. Which is fine I’ve got another 11 or so slides and I can show a few things on Fulcrum to make it more interesting.

My slide show started out with a brief intro and going “I’m not on any boards” – but then I realized 2 or 3 people at the meeting had been with me on a board and – eh – I probably shouldn’t point out I left the board I was with them on so – no worry I’ve got 10 or so slides. I started second guessing my presentation and went down to 9 slides. For the final slide I actually went so far as to mock up a budget on the Full ESRI deployment vs a Hybrid Open Source/ESRI deployment. The problem with that is when you show someone two numbers (60k vs 5k) that are so wildly different people immediately start questioning WHY….the explanation when you’re in room full of ESRI software users and people who worry with budgets is interesting. I glossed over that one – It’s a good slide – it’s just a hard pill to swallow. I’m going to rework it and present it differently. The numbers stand on their own – it’s just hard for a lot of people to see the numbers. Overall my presentation was sorta Meh. It will get better.

So the big deal – there were 4 presentations at the meeting. 3 of which inadvertently mentioned QGIS. One from a vendor (our data can be pulled into QGIS), one from a student (I did my entire project in QGIS), and mine (I’m rolling out a full QGIS PostGIS Deployment for a water utility). A few years ago that wouldn’t have happened. The other presentation covered LIDAR in the state of Tennessee and I had the chance to reference this discussion in front of a guy who can help in the process. Right now I’m building a brief tutorial of processing LIDAR in GRASS.

A Meeting with no plan on a theme in heavy ESRI territory had 4 mentions on FOSS4G. FOSS4G is making a dent in the world of GIS. You could go so far as to say “I’m in the middle of nowhere TN and we had 4 mentions of Free and Open Source Software for GIS”. On the drive back I received a conference announcement where their entire workshop offerings are ESRI based. If you’re planning a conference – seriously PUT SOME FOSS4G IN IT. It’s 2016. You do your conference and yourselves a dis-service if you don’t. Period. Change is good.

Friday I was just sitting here going “It’s been a weird week and I’m tired” and my email beeped “Can you come talk at our meeting?”. Yes – what do you want me to talk about? “Anything you want”. Heh. Will I have internet access?

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