December 2015

Well, like everyone is saying, I cannot believe that 2015 is drawing to a close.  Where did the year go?  This will be a short note – I have to get some Christmas shopping done!

We finally released LP360 this past week.  Our early postponement was to squeeze new features into the products whereas the later delays were to ensure stability.  We have been using the products in our internal production processes for the past few months.  This has been a great experience in terms of fine tuning features and monitoring stability.

One of the things we have been focused on is production processes.  Of course, repeatable process is what the GeoCue workflow products are all about so this is not a new thing for us.  We have always appreciated that quality is most directly related to rigorously controlled processes, not to the heroics of individual production folks.  Now that we are doing a lot of field work, we are examining ways to improve this aspect of the process.  For example, the field work associated with acquiring mine site data with an sUAS is tricky.  It is not that the individual steps are particularly complicated, it is that there are a lot of steps that must be successfully accomplished in a specific order.  We are currently using a lot of checklists.  This is the minimum required to be successful.  How do we improve this process in harsh environments that often lack connectivity to the outside world?  No clear solutions yet but we are working on it!

We have also been working on simplifying our business structure.  We acquired QCoherent Software LLC (a Colorado-based company) in 2009.  Over time, we have moved all of the company to our headquarters in Huntsville, Alabama.  We are finally absorbing the corporate structure into GeoCue Group.  You will not notice any changes other than communications related to LP360 and LIDAR Server now being from GeoCue Group Inc.

We will soon be releasing Service Pack 4 for the GeoCue product set.  The next major release will be in 2016.  We are working on some simplifications to the product as well as better schemes for archiving products.  I think you will appreciate these changes.

Terrasolid is now offering a true 64 bit version for MicroStation CONNECT (the version of MicroStation that succeeds V8i).  Maintenance customers will have access to this new version of Terrasolid tools.  We do caution however, that this is still in the beta stage and is probably not sufficiently stable or feature complete to introduce into production.   We estimate that this new version will be production ready by the end of Q1 of 2016.

During this past year we have learned an incredible amount about how to design sUAS for mapping as well as the tools and processes needed to create products.  This overall workflow is fundamentally changing small area mapping but it is not easy to achieve accurate and repeatable results.  We now have come to realize that mine site mapping requires control 100% of the time and establishing this in dense image matching workflows is not at all straightforward.  I think this is good news for the professionals out there providing these services.  In the area of metric mapping, you will not be easily displaced by someone buying an inexpensive drone and a point cloud generation software application!

All of us here at GeoCue Group wish you a very relaxing holiday season and the very best of success in 2016!

FacebookTwitterGoogle+LinkedInShare

November 2015

First of all, I have to apologize for us not releasing LP360 at the end of October as I promised in the last issue! We needed to add a feature to LP360 to assist with very dense data sets. This new “Classify by Statistics” point cloud task can be used for a variety of functions, among them data thinning. We also took the time to tune a number of different performance bottlenecks, including clipping contours to a project boundary.

We have entered the services business in a small way. We have encountered a number of mine operators who want to collect maps and volumes of their sites using small unmanned aerial systems (sUAS) but they are not yet ready to internalize the process. To assist with this transition, we now offer flying and data processing services to these customers. We do the bulk of this production in LP360 with a bit in our GeoCue workflow products.

One thing this foray into production is teaching us is the value of removing “clicks” from the production process! We are usually so focused on adding advanced features to our products that we overlook the simple things that can greatly improve the speed of a workflow. For example, we changed the destination class selector in the profile classification tool in LP360 to remember the destination class. This is a simple change that took a developer about 1 hour to incorporate. It now saves a data production technician many clicks in the classification process. You can be assured that we will have a renewed focus on basic productivity going forward!

We are in the midst of product planning for 2016. I think we have some pretty exciting developments in the pipeline. I will highlight a few here; you will be hearing details of these as 2016 rolls out.

On the GeoCue workflow software front, we intend to focus some energy on simplifying the product. When we first brought GeoCue to the market in 2004 (we started building the product in 2003), the average production shop employed technicians who were accustomed to “tool box” software with very complex features that a user could stitch together into a workflow that suited their particular needs (sound a lot like the ArcGIS desktop products, right?). Now we find many organizations who are constructing workflows that they would like to be more “black box” and that just work out of the box. This is not unusual to see this occur as a technology such as LIDAR matures.

Our cloud-hosted products, LIDAR Server and Reckon, will see major capability additions in 2016. LIDAR Server will continue to be the premiere solution for managing and delivering LIDAR data in point cloud format whereas Reckon is the life cycle management and storage environment for mine site sUAS mapping. Already we have added the ability for Reckon to serve as a WMS server for clients such as ArcMap and Autodesk. This allows a mine site engineer to bring up to date site imagery and vectors into these environments without the need to take physical delivery of this voluminous data.

Reckon is our first “subscription-only” product. Hosted in Amazon Web Services, this data portal is evolving into a system not only for reviewing mine site mapping by site and mission date but also for annotating stockpiles and planning the next mission. The huge advantage of this over more traditional means, such as trying to use Google Earth imagery, is that the mine engineer can use the most recent view of the mine (for example, last month’s flight). This is nearly a requirement since the topology of these sites are so dynamic.

We are also modernizing the display architecture of LP360 to take advantage of advanced features in workstations and laptop video hardware. Advanced capabilities such as hardware rendering that were once found only in high end video cards are now common place, even in lower end laptops. The 2016 software base will “discover” graphics features and use whatever hardware capabilities found in the discovery process. We will, of course, support fallback to software algorithms for those machines lacking advanced features.

2015 will be the final release year for GeoCue Group software products to support Windows XP as well as 32 bit operating systems (other than our 32 bit LP360 extension for ArcMap). The “experimental” and final releases of 2016 will support Windows 7 and beyond, in 64 bit only. It has been quite some time since Microsoft ended support for Windows XP. We no longer receive development support for XP in Microsoft Visual Studio (our development environment) and thus must retire support for this venerable operating system.   Many other vendors such as ESRI have already ended support for XP so those still on this system should plan accordingly.

For those of you in the United States, we wish you a very enjoyable Thanksgiving holiday!

Best Regards,

Lewis

October 2015

A special thanks to our customers who attended the LP360 software training that we held at our offices in September. As this core group of customers can attest, a few days invested in training on the latest features and techniques can save weeks of time in production and analysis. I think we all particularly enjoyed the evening social at the Blue Pants Brewery!

Several of us have just returned from a whirlwind three weeks on the road. We attended the American Society for Photogrammetry and Remote Sensing (ASPRS) unmanned aerial system conference in Reno, Nevada at the end of September. We conducted (along with Dr. Qassim Abdullah of Woolpert) the UAS Workshop on the day prior to the conference. We had over 110 participants so the interest in sUAS mapping is only growing.

We next attended the inaugural Commercial UAV Expo hosted by Diversified Communications (the folks who bring you ILMF and SPAR) in Las Vegas, Nevada.   This show had well over 100 exhibitors and about 2,000 attendees. We presented a paper on some of the practical aspects of stockpile volumetrics (sort of a lessons learned overview). I was pleasantly surprised at the number of potential end users who attended this conference. We were constantly busy at our booth discussing mine site mapping with quarry and stockpile owner/operators.  Hopefully it was a mere coincidence but the booth next to ours was a company selling automatic parachutes for multi-rotors!

Many companies who are using point clouds extracted from camera carrying drones are realizing that workflow tools beyond those supplied within the point cloud extraction software are needed to efficiently extract products. We have been seeing a nice uptake of LP360 for sUAS by this set of production companies. Our 2015.1 release (by the end of October, I promise!) includes a few new tools such as an automatic stockpile toe extractor that really speed up these processes.

We have been very heavily involved in collecting mine site surveys using our AV-900 sUAS platform. These engagements have been very enlightening in terms of informing us of the tools that can really make a difference in this type of work. One thing we have paid particular attention to is the frequency with which we are denied access to site areas for placing survey control. Fortunately we have our initial version of a Real Time Kinematic (RTK) positioning system on the AV-900 (we actually use this in Post-Processed Kinematic mode). This allows us to collect mine site data with no control at all (we usually do place some checkpoints to verify accuracy). We have come to realize that this is not a nicety for mine site surveys but rather a necessity.

On the LIDAR front, the USGS 3DEP program continues to gain momentum with a number of new projects underway. An interesting aspect of 3DEP is that the deliveries are required to be compliant with the ASPRS LAS 1.4 format. Both GeoCue and LP360 have been compliant with LAS 1.4 for some time now and offer workflows to realize these delivery requirements.

As we move well into the fourth calendar quarter of 2015, we are heavily engaged in product planning for 2016. I see a continued uptake in the use of small unmanned aerial systems for local area surveys and hence we will continue our rapid pace of tool development for this market. LIDAR continues to be a major data source for base mapping with ever increasing expectations on data density and accuracy. We intend to keep LP360 at the forefront of technology for processing and deriving value from these data. I see cloud based services as a technology that promises to provide a means of controlling capital expenditures as data densities expand. While data transfer speeds remain a problem (e.g. they are much too slow), we are developing some clever ways to use hybrid deployments to reduce this impact.

Until next time, enjoy some fine fall weather!

FAA Exemption, LIDAR Server and a New GeoCue Workflow

We have had a lot of things going on in August from finalizing a new client interface for LIDAR Server to receiving our Section 333 Exemption from the FAA. In addition we have started a new workflow integration project that will see a major image processing system hosted in Amazon Web Services (AWS).

In addition to a number of new software developments, we are embarking on offering cloud-hosted subscription services in several different areas. Earlier this year, we introduced Reckon, our AWS-hosted data management and access system for stockpile volumetrics and mine site mapping. This is a subscription service based on sites and data volumes. It relieves local quarry owners from the burdens of managing on-premises servers for housing digital mine site mapping data. Via a web interface, mine operators can rapidly view site data, download reports and analyze site changes over time. We are very pleased with this system and have already begun to host customer data. You can have a look through a demonstration site at www.airgon.net.

We have also just completed a major update to LIDAR Server. LIDAR Server allows you to store, visualize and distribute point cloud data via a rich JavaScript web interface. LIDAR Server can be hosted on a resident server or in a hosted environment such as Amazon Web Services. LIDAR Server is available as a purchased server software package or as a subscription service. We will soon be enhancing the client-side of LIDAR Server with direct launching of LP360, our workstation-based point cloud exploitation solution. If you are a local government who is receiving LIDAR data (perhaps via the USGS 3DEP), hosted LIDAR Server should be a serious consideration. Your data are securely hosted in AWS and managed by GeoCue. You pay a simple monthly subscription based on the amount of data that we are managing. You can test drive LIDAR Server at www.lidarserver.com. By the way, LIDAR Server is the technology selected by the US Department of Agriculture for their nationwide LIDAR data storage, browsing and dissemination.

On the AirGon front, we have decided to offer mine site volumetrics and topographic mapping services. In support of this, we applied for a Section 333 small Unmanned Aerial System (sUAS) Exemption from the Federal Aviation Administration (FAA) to enable us to fly mine sites. I am pleased to announce that this exemption was approved in August for our very own AV-900 Metric Mapping Kit. If you are a services provider, you may look at us and say “why should I purchase an AV-900 MMK from you? It looks as if you are going to be competing with me!” In reality, our goal is to evangelize sUAS technology to the surface mining community for efficient data collection. We are more than happy to turn collection services over to our service provider customers! It is simply that we have realized that mine site owner/operators want some proof that the technology actually works and a clear path to migrating from their current techniques. In fact, we have a very attractive revenue sharing program with Reckon for our service provider partners.

On the workflow front (the original core business of GeoCue), we have just been awarded a new project to build a complex image ordering, processing and discovery system in Amazon Web Services (are you beginning to see a pattern here?) This system will allow users that are geographically dispersed to participate in all aspects of the workflow. We are honored and excited to have been selected for this development. We have built a number of cloud hosted data management systems. This new project will prove that the time is now for cloud-hosted processing system. You will be hearing much more about this project as it develops.

Finally, we intend to do the formal release of LP360 at the beginning of October. We have added a few new capabilities since the EXP release as well as polished a few interfaces. Immediately following the release of 2015.1, we will be embarking on a major rework to the display subsystem of LP360. We now routinely encounter point clouds with high Z extent as well as very high densities (100’s to thousands of points per square meter). We are working hard to ensure that we remain the most responsive visualization platform for this type data.

Well, this month I see I have focused entirely on our technology (I can’t help it – this is exciting stuff!). Next month we’ll talk a bit of business again.

Best Regards,

Lewis

Development, Windows 10, and EXP LP360 2015.1

We are entering the hottest and most humid part of the year here in Alabama so, like January, this is a good time to stay indoors and do things like system design!

We do a lot of system engineering and development work here at GeoCue. This ranges anywhere from customizations of our GeoCue workflow tools to new (“green field”) developments. I have noticed that more and more frequently we consider cloud hosted environments such as Microsoft Azure and Amazon Web Services (AWS) as our solution platform. Besides fractional scaling (add more when you need it, remove it when no longer needed and pay for only what you use), we really like the data storage options. Prohibitively expensive just a few years ago, you can now consider archiving all of your production data in the cloud. For example AWS offers its Glacier archival storage for less than $125 per Terabyte per year. There is just no way to do this on premise with the level of assurance of no data loss that you can get with AWS. At any rate, cloud deployed solutions make more and more sense as this paradigm matures. It is rather ironic since when my great granddaddy started in this business he was renting access to a remote time share system. The more things change, the more they stay the same!

I just upgraded my workstation-class laptop to Windows 10. Since I was moving from Windows 8.1, this has been a positive experience. I have not yet had a lot of experience with the various capabilities so the jury remains out on which is better for workstation (no Microsoft, we don’t do image and LIDAR processing on tablet PCs !!) – Windows 7 or Windows 10? There is a detailed story of my installation experience in this newsletter.

If you are an LP360 customer on maintenance (thank you very much!), you may have already installed our 2015.1 EXP release (yes, it finally went out the door!). The purpose of the Experimental release is to provide you with an early look at some of the features we are adding to the official release. Examples in the current EXP release include three new major tools:

  • Live View – A completely redesigned, real time interface for filtering the display
  • A Ground Cleaner Point Cloud Task (PCT) – this new PCT (available at the Standard level) is a tool that allows you to very rapidly clean up areas of ground classification that are incomplete (a common problem in delivered LIDAR data)
  • An Automatic Stockpile Toe Extractor PCT – This is a tool still in beta form. It allows you to automatically create polygons at the base of a stockpile by simply selecting a point on the pile. This tool really speeds up volumetric analysis

If you are not currently on maintenance, contact Ashlee Hornbuckle at ahornbuckle@lp360.com and she can assist you with returning to the program.

We will soon be moving our licensing to a cloud-hosted solution. This will make self-service of common licensing operations possible. We’ll first move LP360 and then look at our other products. This will take a bit since we have to do this development in-house.

OK, enough said! I have to get back to work! Have a great remainder of the summer!

Best Regards,

Lewis

LP360 Testing, Metric Mapping Kits and a New LIDAR Server

I spent the week of the Fourth of July at my beautiful retreat on the lovely Tennessee River, ostensibly on holiday. In reality, I was sitting with my laptop at the kitchen table writing magazine articles. I am not complaining though – the view is fabulous!

I was also very busy delaying our experimental release of LP360. I did a complete run-through of our new Live View display filter, sending multiple suggestions for tweaks to the development crew and testing out their new builds. On some days we cycled three builds! This is a real advantage of working from Casa Rio. If I were at the office, they would probably knock me in the head! The effort will be worthwhile – this has turned out to be a very nice tool for quickly modifying the display of point cloud data.

I am pleased to report that sales of our Metric Mapping Kit are beginning to take off (pun intended). The AV-900 MMK is a bundle of all of the hardware and software needed to do local area metric mapping and volumetric analysis. We have now collected test data over a wide variety of sites with much effort expended on analyzing metric accuracy as a function of variable parameters such as control, RTK, stockpile toe definition and so forth. The results are truly stunning. sUAS technology will be a paradigm shift for this type of analysis.

I am also pleased to announce (there will be a press release in the next week or so) an option for filing FAA 333 exemptions for the MMK. If you purchase an AV-900 MMK, we (well, actually our attorney) will file your complete FAA 333 petition for a flat rate of US $1,295.

Speaking of stockpiles, the EXP release of LP360 (I promise we will release this by 15 July!) has a new point cloud task (PCT) for automatically digitizing the “toe” of a “clean” stockpile. Simply click a point on a pile and – voilà – a 3D stockpile toe! This tool is showing great potential and will be refined as we work on the final 2015.1 release. Our goal is to make stockpile collection as simple and repeatable as is possible. This function will be available in the Windows (“standalone”) release of the Standard/sUAS level of LP360 at EXP but will be in the ArcGIS extension by the time we deliver the final 2015.1 release.

Have a look at the latest iteration of LIDAR Server. You can view demonstration data sets by visiting www.lidarserver.com. We have replaced the legacy Silverlight client interface with an all new JavaScript browser. LIDAR Server is a great technology for hosting county-wide LIDAR data deliveries, making them available to constituents for viewing and ad hoc deliveries. For example, if a county engineer needs LIDAR data in the vicinity of a road intersection, she can just digitize an area of interest in the LIDAR Server client and download the dynamically created LIDAR data set to her workstation. We are doing a lot of work on LIDAR Server so there will be more to come!

Speaking of servers, our Reckon volumetric results management system has reached what might be called “version 1.0” ready for use. Reckon is a hosted service, running in Amazon Web Services (AWS). It is aimed at both owner-operators of surface mines as well as service providers. Right now you can experiment with Reckon by contacting us for an account. By the end of this month, we will have a new Reckon web site up with a live, on-line demo; stay tuned!

Keep enjoying your summer – see you in August!

Lewis Graham, CTO GeoCue Group

3DEP, LP360 Toolbox and AirGon

I am looking for the month of May – it seems to have disappeared without a trace!

We recently visited with the Tennessee Office of Information Research (OIR) in beautiful Nashville, Tennessee. The OIR is the coordinating state agency for a USGS 3DEP LIDAR (3 acronyms in a row – not quite a record!) acquisition project. Under this program, the state of Tennessee will be flown at Quality Level 2 (2 points per square meter) over a four year period. The initial collection (slated for this fall) will encompass some 11,500 square miles, covering 27 counties.

3DEP is an excellent opportunity for state and local government agencies to pool their financial (and often technical) resources to obtain point cloud data. By spreading the cost across a spectrum of stakeholders, a surprisingly large amount of data collection can be accomplished.

Our discussions with the OIR led naturally to a conversation about how LIDAR data are used in GIS and engineering departments. We covered the usual suspects such as flood plain analysis, basic 3D visualization, site planning and so forth. By the end of the conversation, I was convinced (as usual) that every single state and local government GIS workstation should have access to a current image and current 3D (e.g. LIDAR point cloud in LAS format) backdrops. Why would anyone find it acceptable to be without a cross-sectional view of their municipal data on an ad hoc basis? Mainly because they have never had this level of information available. You never miss what you have never had!

When we returned to the office, we decided to put together, once and for all, a package of material for folks who are either contemplating acquiring LIDAR data or those who have access to LIDAR data. We will develop use cases and return on investment information for the range of applications that make sense for these data. If you have some novel ideas and particularly case studies, please work with us. Obviously we want to sell more software but we believe a rising tide lifts all boats. We need to get the tide (meaning the understanding and effective use of LIDAR data) rising first!

Speaking of software, we hope to have our experimental release (EXP) of LP360 available for download by the end of this month (June). The developers are doing fine. It is me who always throws a wrench in the delivery schedule – “let’s get return selection added to the new Live View dialog before we release…” Speaking of Live View, this is a new dynamic filter in LP360 that lets you change class, return and flag filtering on the fly. You are really going to like this new feature!

While we try to make features in our tools easy to use, the LIDAR tools on the market still tend to be toolbox oriented rather than workflow specific. For this reason, it is very important to participate in training if you hope to realize a maximum return on your investment. We offer a range of training (and consulting) from web based to on-site. In addition, we have our Huntsville-based LP360 training coming up in the fall.

On the AirGon side of things, we have been talking to a lot of potential clients who can make immediate use of small Unmanned Aerial Systems (sUAS) mapping. We offer a complete helicopter-based metric mapping kit in the AV-900 MMK. This is garnering a lot of interest since it provides a turn-key solution of hardware, software and training for doing jobs that have an immediate high return on investment such as stockpile volumetric analysis. However, we also offer just the piece parts for those who wish to assemble their own system. For example, if you have decided on a small wing type sUAS such as the eBee from SenseFly, LP360 for sUAS is still your best option for extracting volumetrics (anyone who has tried to do a multi-pile site using the point cloud generation software shipped with these systems will readily agree!). In addition, AirGon Reckon is the best product in the market for hosting and delivering mine site orthos and volumetric reports. By hosting our volumetrics delivery system in Amazon Web Services, we relieve you the need to worry about data delivery to multiple offices, data backup and security.

Summer promises to fly by just as quickly as the spring. We are attending a number of conferences such as the ESRI meeting and the Transportation Research Board AFB-80 summer meeting. If you are attending one of these, please look us up. See you in July!

Drones, Metric Mapping and RTK

We have been very busy this first third of 2015 with software development (as we always are).  The thing about software is that it is never static.  It is either undergoing new additions or entering the end of life phase.  We have had a very big focus on ensuring that our products are optimized for LAS 1.4 support as this is the new requirement of the USGS.  Additionally, we like to use LAS 1.4 in our mine site workflows since it supports a few nice capabilities that were not in LAS 1.3.

This is definitely the year of the drone.  Every major geospatial hardware firm has announced a drone system for remote sensing (some for metric mapping).  While the USA is inching along toward some usable drone rules, other countries have clear rules in effect and drone mapping is becoming a standard survey/mapping tool.

We are garnering a very high interest in AirGon’s Metric Mapping Kit (MMK).  This solution provides everything you need to do uncontrolled mapping projects using a small Unmanned Aerial System (sUAS) except a processing laptop computer.  Add in your own surveyed control points to reach survey grade accuracy.

Speaking of the Metric Mapping Kit, we will be hosting a AV-900 MMK workshop in Toronto, Canada on June 11th and 12th.  Thanks to Jim Giordano, we will be presenting live flight demonstrations at VicDom Sand & Gravel as well as an in-depth look at mission planning and post-collection data processing.  Our focus will be on drone-collected volumetrics. Personal protection equipment (steel toed boots, hardhat, safety vest and safety glasses) are required.  Remember that a passport is required for travel between the USA and Canada.  Space is extremely limited so sign up early!

We have been (in a joint project with Applanix, a Trimble Company) researching the use of Post-Processed Kinematic (often erroneously called Real Time Kinematic, RTK) control solutions.  Obviously everyone flying a sUAS for metric mapping purposes would like to dispense with the tedium of deploying ground control.  We will publish the results of our efforts as a white paper when the work is complete.  My goal is a recipe, if you will, of the methods that are appropriate for a given desired accuracy level.

We will be posting an experimental (EXP) release of LP360 (all license levels) within the next few weeks.  Those of you on software maintenance will be able to download this release via the “Check for Updates” option under LP360 Help.  There is a separate article in this newsletter that provides a highlight of the new features.

Till June – Best Regards,

Lewis

GeoCue Group News – May 2015

April 2015

We’ve had a very busy first quarter with many road trips and demonstrations of technology. I continue to remain very excited with respect to small unmanned aerial systems (sUAS or drone) technology. Applied to the right sort of problem, this is a real game changer.

We just attended the SPAR conference in Houston last week. SPAR is a conference with a primary focus on tripod (static) laser scanning and secondary foci on mobile laser scanning and an emerging section on sUAS technologies. The conference was attended by perhaps 1,000 folks. We were exhibiting as AirGon in the UAS section of the exhibit hall. If you are involved in building information management (BIM), this is a must-attend conference.

I made an interesting observation regarding the emergence of sUAS technology for mine site mapping.  It reminds me a lot of the years when tripod laser scanning was emerging and replacing total station surveys in brown field as-built documentation projects. sUAS mapping is the logical choice for volumetric mapping at mine sites. While it has some disadvantages, its pluses put it ahead of any other technique for this sort of application. For the first time, I encountered service providers who are using other approaches to solve this problem. Many of those who are using tripod scanning for volumetrics feel threatened by this newly emerging technology. Who can blame them? If I had just invested 80K in a laser scanner for volumetrics and then observed a technology much more suited to the task, I would be defensive as well! Thus I am seeing end-users (e.g. mine owners) as the parties most embracing of sUAS mapping with service providers being drug into the space by their customers. This is, ironically, not unlike the situation when tripod laser scanning was emerging. Service providers had big investments in total stations and had no burning desire to have to invest in a new technology.

We are changing our newsletter a bit with this issue. We will now be hosting information such as our tool tips and how-to articles in our new GeoCue Group knowledge base. We will put a lead-in sentence in this newsletter that will link you to the knowledge base article. This will be a real benefit as time goes on. The Knowledge Base includes a robust search capability and consolidates all of this rich information in one spot. This means that if you need to review our extensive past article on breaklines, you can simply search the knowledge base rather than digging through the newsletter archive. We are gradually moving all of the past technical articles over to the knowledge base.

We continue to focus a lot of our development efforts on LP360. These developments range from ease of use to advanced methods for creating the toes of stockpiles for volumetric analysis. In addition, we have been tuning our display subsystem to increase window refresh times and reduce our memory footprint. Finally, we are adding (to the Standard level) a new point cloud task for cleaning up areas where batch ground classification did not quite do the job.  We will be posting an “Experimental” release of LP360 within the next several weeks that provides initial versions of these features.

Thanks very much for being a GeoCue Group customer or an interested observer! See you in May.

Best Regards,

Lewis

GeoCue Group News – April 2015

Accuracy, Precision and all that

I was recently at a Transportation Research Board subcommittee meeting where we were discussing accuracy and precision (no one used the word “resolution”). After listening for a bit, I realized a sense of Deja vu. It was a TRB meeting several years ago that inspired me to write an article for my column in LIDAR News (“Random Points”) on this subject. I am repeating the essence of that article here since there is a follow-on discussion that requires this foundation.

There is a lot of argument out in the data acquisition community surrounding these topics. It nearly always comes up in arguments about why a particular vendor’s aerial data is better than that stuff on Google Earth®. There is also the old saw – “bad data is better than no data.” Of course, depending on your use, you better be able to quantify how bad and in what ways.

It’s no wonder that a lot of confusion exists over quantifying accuracy. Every time I have been in a room full of experts, we argue about the specific meaning of the terms. Since I have the floor here for the moment, we’ll go with my descriptions! A caveat however – this article is meant to provide a bit of insight. It is not a vetted technical article and thus you should use my descriptions and analogies with a lot of caution.

We will specifically look at geopositional accuracy as opposed to other accuracy issues such as attributes (i.e. is the ‘color’ attribute correct?). For a more detailed look at geopositional measurement, I think the Washington State DOT “Highway Surveying Manual” is an excellent read (easily found on the web). On the other hand, I find the FGDC standards very dry and light on explanation.

To discuss the geopositional quality of data, I think you need to fully understand the following terms:

  • Network Accuracy (often called “Absolute Accuracy”)
  • Local Accuracy
  • Precision
  • Resolution
  • Density

There is no other way to do this than to just jump in so here we go!

Pick up a ruler and look at it. The fineness (spacing) of the tick marks is the resolution. Similarly, if you have a digital volt meter, the number of digits in the display determines the resolution (it’s a bit more detailed than this but this is close enough for our purposes). Note that this parameter has nothing to do with ‘precision’ or ‘accuracy.’

Precision is a measure of the repeatability of a measurement under identical environmental circumstances (meaning, for example, that if you made repeated length measurements with a steel tape over a number of days where the temperature varied, you would violate the ‘identical environmental conditions’ restriction). It always speaks to repeating the same measurement multiple times. Since in LIDAR and imaging work, we very seldom do repeated measurements, this is perhaps the most misrepresented term in our work. Here is a simple experiment that illustrates precision. Take a tape measure and measure the height of a door. Now, using the exact same measurement spot, tape and technique, repeat this 9 more times. Write down your readings to the highest level of resolution supported by your tape (remember resolution?). The range of your readings gives you a measure of the precision, not only of your device (the tape) but your system (where you place your eye each time, how close you are at measuring the same spot, how hard you pull on the tape and so on). The assumption here is that you are measuring some constant object so that variation is solely due to you and your device, not the object being measured. In reality, this may or may not be the case! Now those of you who have studied basic statistics know that if you repeat these measurements enough times (say 30), a plot of the results will produce the ubiquitous Normal (Gaussian, bell, etc.) curve. Precision is statistically quantified as variance (or standard deviation). Now notice that a tape made of steel and a tape, with identical ticks, made of rubber, will have the same resolution but radically different precision.

I hope that you notice that we still have not touched on accuracy. For example, suppose we did our experiment of making 30 repeated measurements of the height of a specific spot on a door with an uncalibrated (more on this later) tape having a resolution of 0.001 meters. Suppose we came up with an average measurement value of 2.000 m, a largest reading of 2.002 m and a smallest reading of 1.097 m (for you statisticians, let’s say we have a standard deviation of 1.8 mm). What can we say at this point? Well, the resolution of our tape is simply a given (we will ignore fudging resolution by linear interpolation). Our measurement precision is quite “good” with a maximum deviation of only 3 times the resolution of our tape. However, we cannot say anything at all about accuracy!

Here’s the problem. I can just go in to my workshop and whack off a piece of electrician’s steel fish tape. I can mark it with measurements (OK, this would be pretty tedious, I agree!) by just eyeballing. and voilà, I have a steel tape! It would be quite precise if I did not subject it to temperature variations during my sequence of 30 measurements. However, it would, no doubt, be quite inaccurate when compared to a known length. And this is key – you cannot make a judgment about accuracy without having a ‘standard’ to which you are making comparisons.

In geopositional work, we are concerned with two types of accuracy. Network Accuracy (which I usually call absolute accuracy but this is a really loose term) talks about how closely your measurements match a known external reference system (what we call a ‘datum’). Local Accuracy (also often called relative accuracy) deals with the accuracy of the measurement of metric units with respect to a standard. By this we mean if you measure a length or an area, how ‘close’ are you to the true value? Note that you can very accurately measure the distance between two fixed points yet be clueless as to the location of the points relative to some outside reference system (again, the ‘datum’). This is the case with our measurement of the door. If I calibrated my tape by comparing to a ‘standard’ meter, I could then use it to very accurately and precisely (the precision coming from my construction of the tape as verified in my repeated measurements experiment) measure the height of the door. Yet I still would have no idea of where in the ‘world’ the two end points of my measurements were located. This is an example of very good relative (local) accuracy yet very poor network (absolute) accuracy.

So finally we are left with the term, density. This parameter is not related to accuracy, precision or resolution. In LIDAR work, it would be the number of points per unit area. In imagery work, it would be the number of pixels per unit area. Note that this is often called ‘resolution.’ In imagery work, if using an array sensor, it may be roughly synonymous with resolution. When using scanning LIDAR systems, it is seldom synonymous with resolution. Am I splitting hairs here? No, not at all. If you followed the above discussion, you will realize that precision is based on a quantum number and the size of the quanta is the resolution, not the density (or point spacing). In looking back over this paragraph, I have confused even myself! Basically what I am saying is that it is entirely possible to limit the scanning density of a LIDAR system to roughly 1 point per meter yet have an available horizontal resolution of a few centimeters.

Figure 1 provides a nice physical representation of these terms. Note that resolution would be the width of the target rings. Here we are imagining that the bulls eye represents a known location in our datum (maybe we placed some rings around a National Geodetic Survey monument and are taking pot shots with the old Winchester!).

Acc and Precisoin, fig 1

Figure 1: Accuracy, Precision, Resolution

A figure that I lifted directly from Wikipedia (Figure 2) provides a more statistical view of accuracy versus precision. Note here that the distance of the mean (average) of the repeated measurements speaks to the accuracy whereas the ‘spread’ of the measurements (variance) speaks to the precision.

Accuracy, fig 2

 

Figure 2: A more statistical view of Accuracy and Precision

With this foundation in terminology, we will address how these factors play in to LIDAR and other point cloud data – stay tuned.