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Saturday, March 23, 2024

Ten Things You Need to Know About Indoor Positioning

This article was originally published at Directions Magazine on May 6, 2013.

1. GPS does not work well indoors

While today’s more sensitive GPS chips can sometimes get a fix (receive signals from enough satellites to determine a location) inside a building, the resulting location is typically not accurate enough to be useful. The signals from the satellites are attenuated and scattered by roofs, walls and other objects. Besides, the error range of many GPS chips (tennis court) can be larger than the indoor space itself (small grocery store)!

2. Some indoor positioning solutions work similar to GPS

Locata, an Australian company, offers beacons that send out signals that cover large areas and can penetrate walls. Locata receivers work similarly to how GPS receivers work. The U.S. Department of Defense is an early Locata user.

Nokia uses beacons that send out Bluetooth signals. While any Bluetooth device can read them, they only cover a few square meters. Nokia last year set up the In-Location Alliance with 22 companies to further develop a Bluetooth locating solution (press release).

Many companies tap into Wi-Fi signals that are all around us - including when we are indoors. With a good map of the locations of the access points, a Wi-Fi receiver like a cell phone can be located even indoors (Wikipedia). Google, Navizon and Skyhook are among the leaders in this area.

 TruePosition, which offers a cell tower locating solution, acquired the intellectual property of Rosum (APB coverage). Rosum taps TV signals for location determination.

3. Other solutions use light or magnetic fields to determine location

ByteLight sends flickering light patterns from its LED light fixtures. The receiver (a camera on a phone) reads the code and sends it to a server. On the server the code is compared to those a map. A match means the receiver is under a specific “light.”  

IndoorAtlas, a start-up based in Finland, surveys buildings for their internal magnetic map. The fields vary within the structure, providing different fingerprints for different locations. A cell phone’s internal digital compass can be used to detect the field and, much like ByteLight’s procedure, compared to the map for location determination (Economist coverage).

4. RFID and inertial systems work very differently

Passive radio frequency identification tags (RFIDs) prompt a transaction when they pass near a sensor. For example, a closed door prompts the user to swipe the card to pass. Doors or gates force users into a queue or to slow down for the sensor to work properly. These passive systems detail only that a person or object entered a room; they do not provide detailed location information within the room.

Active RFID tags are self-powered and regularly send out signals to receivers within the area of interest. This is the reverse of GPS. Knowing the location of the receiving sensors allows for accurate indoor locating in near real-time.

Solutions that use inertial measurement work only if a starting location is know. With that information collected, these sensors use accelerometers, gyroscopes and other sensors including clocks to track orientation and distance to keep track of location in near real-time. The latest inertial solution, from DARPA, is a chip smaller than a penny (press release).

5. Indoor positioning detects the location of a person or object, but not always its orientation or direction

While indoor positioning systems can determine location, many need additional information to determine which way a person or object is facing. That can make providing directions or pitching a product in a store more challenging. 

The addition of an electronic compass to a receiver (many cell phones now have them), or a microelectromechanical systems (MEMS) orientation sensor or a prompt to turn toward a particular direction (to scan a bar code or QR code on a poster, for example) can provide more information regarding orientation.

6. The best solution for indoor and outdoor positioning may be a hybrid

No single solution works perfectly in all environments. For that reason devices may support more than one positioning solution and switch between them as needed. Today’s mobile phones use GPS (when it’s turned on) outdoors but may switch to Wi-FI positioning (when it’s turned on) when the signal is weak, such as when an individual goes indoors. Indoor location and commerce solution provider aisle411 taps into both Wi-Fi and MEMS sensors for its retail store offerings.

7. Indoor positioning is in demand for a variety of uses

While the goal of indoor positioning for some users, notably hospitals and malls, is to provide navigation aid, others want to use indoor positioning to better market to customers, provide just-in-time information via audio for tours, offer video or augmented reality experiences or connect people of interest in proximity to one another. The U.S. Federal Communications Commission hopes to use indoor positioning to provide timelier and more effective emergency services (see below).

8. Major tech players are working in the indoor space

Apple, Google and Microsoft are all exploring the use of indoor positioning. At this time the effort is focusing on both indoor positioning technologies and creating the basemaps that will make such solutions more valuable.

Google has its own Android positioning system based on Wi-Fi (APB coverage). When some Android developers (Samsung, Motorola) tried to use Skyhook’s solution in place of Google’s, Google sued. That case will be in court, along with a few others, in 2014 (FOSS Patents coverage). Microsoft uses Wi-Fi for indoor positioning, as well, and has some research going on regarding the use of signal strength for location determination. Apple recently acquired WifiSLAM (APB coverage) to get into the indoor location game.

9. The Federal Communications Commission (FCC) is looking at indoor positioning to enhance emergency response

Results of a study conducted in late 2012 and published March 14, 2013 by the FCC’s Communications Security, Reliability and Interoperability Council (CSRIC) suggests a current baseline for indoor positioning for use in emergency response. Three different vendors, using three different indoor technologies, participated (summary).One key concern is determining vertical location, that is, on which floor a person is standing in a multilevel building. The FCC report concludes: “While the location positioning platforms tested provided a relatively high level of yield, as well as improved accuracy performance, the results clearly indicate additional development is required.”

10. Indoor positioning requires indoor maps

Locating a person or device indoors is only half of the solution. For the location to be meaningful for navigation or other purposes, service providers need accurate indoor maps. There’s a new industry creating those data. Micello recently announced it had mapped 15,000 indoor venues (press release). Google, in addition to collecting its own indoor mapping data (APB coverage), is crowdsourcing maps from its proprietors (APB coverage). Nokia (APB coverage) is collecting indoor data and even OpenStreetMap has a wiki page about indoor maps.

Learn ArcGIS: Esri Embraces New Vision for Teaching and Learning GIS

This article was originally published at Directions Magazine on July 13, 2014.

Learn ArcGIS is Esri’s new website for teaching GIS to both new and existing users. The site taps ArcGIS Online, apps and datasets and serves as a portal to other teaching and learning opportunities from the company. Executive Editor Adena Schutzberg has an exclusive look at both the educational vision and the site itself.

A New Vision for GIS Teaching and Learning

What is this new vision for teaching and learning GIS? Aileen Buckley, a cartographer/writer and team member on the project, cited three unique aspects to Learn ArcGIS during an interview in late June. First, Learn ArcGIS embraces a new corporate-wide goal of teaching through problem solving rather than via rote “button pushing.” Careful readers of Esri content might have noticed the term “problem solvers”   was used in Esri’s ConnectED press release announcing free access for U.S. K-12 schools to ArcGIS Online. 

Second, unlike other GIS teaching and learning solutions, Learn ArcGIS requires, for the most part, just an Internet connection. Students access the publicly available Learn ArcGIS website and use a free ArcGIS Online account as a member of the Learn ArcGIS organization. Christian Harder, a writer and information designer on the team, noted students can be up and running in minutes. Some of the content uses ArcGIS for Desktop; students who do not have access to the software are encouraged to download a free trial version.

Third, the problems and examples students will tackle and explore are real. The Learn ArcGIS team is tapping other Esri teams as well as its users for real world problems and datasets. One of the projects (which each consist of one or more lessons) takes advantage of Anne Knowles’ work on Gettysburg’s Civil War battles. The intricate story map encourages users to explore the idea of “line of sight” for a specific purpose: understanding if military leaders could actually see the enemy from their positions.

Using the Learn ArcGIS Website

The Learn ArcGIS website offers a gallery of projects that fall into roughly three categories. 


Some projects teach students with no ArcGIS Online experience the vocabulary and basics of the service. With those basics students should be ready to tackle any of the other projects. 

Building Maps and Apps 

A second project type leads students through building a particular type of map or app. At launch students will find a project that details the creation of an online photo portfolio. 

Problem Solving

A third type of project focuses on using GIS to tackle a particular problem. One of the projects available at launch examines how geography impacts the distribution of breast cancer deaths in black and white women in the United States. A project planned for a future release explores how a real estate agent might use GIS. 

Learn ArcGIS Lesson Gallery

Students can sift through the projects using tools to sort by keyword and industry. At launch there are about a dozen projects and over 40 individual lessons, but the plan is to grow the site with content on a variety of topics from around the world.  New content should appear later this summer. The projects are not just aimed at beginners: an advanced project on geodesign is in the works. The website will have a strong social component so students can interact with one another as they learn.

Each project also serves as a starting point for more learning. Each one offers pointers to related material on the Learn ArcGIS site as well as content from Esri’s training, education and other teams. 

The projects are meant to provide a “holistic view” of GIS, from asking questions to creating maps and then using those maps, per Tim Ormsby, technical writer and a team member. That reminded me of Esri’s discussion of the “Five Steps of the Geographic Approach” and this graphic from 2009. I found a similar graphic in the “Bridging the Breast Cancer Divide” project in Learn ArcGIS.

Impact of Learn ArcGIS at Esri

I first heard about Learn ArcGIS after Buckley presented a paper on the topic at the Association of American Geographers conference in Tampa back in April (see her slides from this presentation). I contacted the Esri Education team to learn more and to my surprise I was pointed to the software products team, Clint Brown’s team. That had me scratching my head.

One of the tasks of the Esri products team is to write documentation. Learn ArcGIS is considered part of, or an extension of, traditional software documentation. Or, as Harder put it, perhaps Learn ArcGIS is “documentation 2.0.” 

Most Esri documentation does a great job detailing what functions do and how to use them, he explained. But there’s little discussion of when or why you might use that feature to address a particular situation or problem. Learn ArcGIS aims to add that sort of context. In time, Learn ArcGIS will be connected to Esri’s documentation. 

In short, said Ormsby, Learn ArcGIS will help break down the teaching and learning silos in the company.

Learn ArcGIS for Educators

There are a number of ways educators can take advantage of Learn ArcGIS. At launch most of the material is aimed at the advanced high school and college level learners. University and K-12 educators can use the resources to develop their own skills. There’s a plan for materials aimed specifically at K-12 students for use by educators taking part in Esri’s ConnectED Initiative. 

Educators can use the openly available data services and openly licensed content within their own educational organization’s ArcGIS Online Organization. Alternatively, they can have each student create an account with the Learn ArcGIS organization. The latter may be preferable for educators with less GIS experience or limited on-site support. As for the open licensing, no specific license was attached to the projects when I previewed the website, but the team assured me they will be “open.” The Learn ArcGIS projects only tap publicly available datasets in ArcGIS Online.

One final note for educators. The projects do not have explicit learning objectives, but they do have lists of skills that will be covered, such as these from “Bridging the Breast Cancer Divide.”

Build skills in these areas:

  • Exploring maps and performing visual analysis
  • Adding fields, selecting features, and calculating values
  • Symbolizing the values
  • Performing hot spot analysis
  • Interpreting findings

The Projects

I previewed the in-development projects before Learn ArcGIS launched. I explored the “basics” project titled “Get Started with ArcGIS Online,” which uses data about Hawaii and volcanos to introduce the ArcGIS Online platform (Figure 4). Then I learned how to “Create a Community Garden Web App.” Finally, I tackled “Bridging the Breast Cancer Divide.”

The self-paced, real world-based projects on the Learn ArcGIS website are essentially tutorials. They include a good number of lessons on specific workflows. The lesson details will look familiar to anyone who has followed a software tutorial.

Step by step instructions

The “Create a Community Garden Web App” provides a recipe to create the app using data from the Tequesquite Community Garden in Riverside, California. The four lessons in the project offer step-by-step guidance even as they teach the student how to georeference a raster map and edit vector data. This is how problem-based learning works: specific knowledge (in this case, georeferencing and vector editing) is acquired on the way to solving the larger problem. 

The “Bridging the Breast Cancer Divide” project begins with the New York Times article that prompted its development. There’s a discussion of the Spatial Problem Solving Approach that I hope encourages motivated learners to veer away from the step-by-step instructions and explore their own questions after completing the nine-lesson tutorial. I would have liked to see a “you are here map” of my progress through the nine lessons - I kept having to return to the project’s table of contents to see where I was. A progress meter, especially for the projects with more than a few lessons, would be a nice enhancement for a future release.

All of the projects provide a solid base in how to use Esri’s GIS software and some insight into its potential to solve real world problems. I want to encourage teachers and learners to use Learn ArcGIS in the best traditions of problem-based learning: as a basis for their own lessons and explorations.