Tag Archives: GPS

Comparing Tracks between Smartphone Apps and Survey Grade GPS Receivers

We have compared different field data collection devices and apps in this blog over the years, including between smartphones and recreational-grade GPS receivers here and here,  and between two smartphone apps.  We have also discussed Esri field apps such as Survey 123 and Collector for ArcGIS.   How do tracks collected with smartphone apps compare to those with a survey grade GPS receiver?

I was recently in the field collecting the rim and the bottom of gullies incised through head cut erosion with some excellent high school students and their instructor from the Santa Fe Indian School.  The instructor brings his students to the same site each year, and over time, it is evident that some of these gullies are very actively eroding.  In a semi-arid region where topsoil is one of the primary natural resources, erosion is a very serious matter.  I like the project because it incorporates time, space, fieldwork, GIS, and GPS, and real-world issues, but most of all because the students are active in experimenting with solutions to the problem, such as the construction of “Zuni Bowls” which can slow erosion rates.

I mapped the tracks that I had collected with 2 smartphone apps (RunKeeper and Motion X GPS) and the tracks collected by students using Trimble GPS receivers running Pathfinder Office.  It was easy to bring the data into ArcGIS Online for comparison purposes from the original GPX and shapefiles.  As you might expect, the tracks from my smartphone apps are quite angular compared to that collected with the Trimble, which have sub-meter spatial accuracy capability.  By contrast, the geo-tagged photographs that I typically use in creating campus story maps, such as this one of New Mexico State University, over the past year,  even though they were collected with a smartphone, have been steadily improving in spatial accuracy.  They are now usually less than one meter away from where I actually took them, as measured on a satellite image base map.  Therefore, point data from a smartphone is often better than line (track) data.  But the track collected on a smartphone with Collector for ArcGIS will be much more accurate than that from my non-GIS smartphone fitness and GPS apps.

But note that I used 2 low-end apps on my smartphone to collect the tracks.  What if I had used Collector for ArcGIS?  As is explained here in these slides, Collector allows collection of data with extremely high accuracy.  Here is an example of Collector being used by a water district with excellent results, and in this video from the field, I explain how educators are using it to collect trees, light poles, curbs, and other information in a city.

As we have mentioned many times in this blog, using geotechnologies in instruction comes down to:  Use the most appropriate tool for the job.  The gullies measured by the students in this study have intricate perimeters, and thus, the higher end GPS receivers were essential. Or, they could have used the Collector for ArcGIS app.  For collecting water quality in streams or trees on your school campus, a recreational grade GPS receiver or a smartphone app might be the most appropriate solution.

Results of comparison of field methods and devices in ArcGIS Online

Results of comparison of field methods and devices in ArcGIS Online.

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Interpreting Our World: New book on 100 Revolutions in Geography

Looking for a new way to teach and learn about geography?  I have written a new book entitled Interpreting Our World:  100 Discoveries that Revolutionized Geography, described in this video.  This book demonstrates why geography matters in the modern-day world through its examination of 100 moments throughout history that had a significant impact on the study of geography—which means, literally, “writing about the earth” or “describing the earth.”

Geography is not simply accounts of the lands of earth and their features; it’s about discovering everything there is to know about our planet. This book shows why geography is of critical importance to our world’s 21st-century inhabitants through an exploration of the past and present discoveries that have been made about the earth. It pinpoints 100 moments throughout history that had a significant impact on the study of geography and the understanding of our world, including widely accepted maps of the ancient world, writings and discoveries of key thinkers and philosophers, key exploration events and findings during the Age of Discovery, the foundations of important geographic organizations, and new inventions in digital mapping today.

The book begins with a clear explanation of geography as a discipline, a framework, and a way of viewing the world, followed by coverage of each of the 100 discoveries and innovations that provides sufficient background and content for readers to understand each topic. Students will gain a clear sense of what is truly revolutionary about geography, perhaps challenging their preconceived notion of what geography actually is, and grasp how important discoveries revolutionized not only the past but the present day as well.

It is my hope that the book clearly provides readers with an understanding of why geography matters to our 21st-century world and an awareness of how geography affects our everyday lives and is key to wise decision making. I have also ensured that the book addresses and explains key themes of geography, including scale, physical processes, cultural processes, patterns, relationships, models, and trends.  The book also integrates time, space, and place in geography, documenting how it is not only the study of spatial patterns, but also the fact that many discoveries in geography came about because of the particular time and place in which the discoverers lived.

The book was published by ABC-CLIO and is available from the publisher and via Amazon.

And yes, the book includes plenty about geotechnologies that we discuss in this blog, including GIS, GPS, remote sensing, web mapping, UAVs, and other technologies from astrolabes and compasses to theodolites and the Internet of Things.

Interpreting Our World:  100 Discoveries that Revolutionized Geography

Interpreting Our World: 100 Discoveries that Revolutionized Geography.

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Mapillary: Capturing, Sharing, and Exploring Street Level Photos

Mapillary is a tool that allows anyone to create their own street level photographs, map them, and share them via web GIS technology.  The idea behind Mapillary is a simple but powerful one:  Take photos of a place of interest as you walk along using the Mapillary mobile app.  Next, upload the photos to Mapillary again using the app. They will be connected with others’ and combined into a street level photo view.  Then, explore your places and those from thousands of other users around the world.

Mapillary is part of the rapidly growing crowdsourcing movement, also known as citizen science, which seeks to generate “volunteered geographic information” content from ordinary citizens.  Mapillary is therefore more than a set of tools–it is a community, with its own MeetUps and ambassadors.  Mapillary is also a new Esri partner, and through an ArcGIS integration, local governments and other organizations can understand their communities in real-time, and “the projects they’re working on that either require a quick turnaround or frequent updates, can be more streamlined.”  These include managing inventory and city assets, monitoring repairs, inspecting pavement or sign quality, and assessing sites for new train tracks.   Other organizations are also using Mapillary:  For example, the Missing Maps Project is a collaboration between the American Red Cross, British Red Cross, Médecins Sans Frontières-UK (MSF-UK, or Doctors Without Borders-UK), and the Humanitarian OpenStreetMap Team. The project aims to map the most vulnerable places in the developing world so that NGOs and individuals can use the maps and data to better respond to crises affecting these areas.

On the discovery section of Mapillary, you can take a tour through the ancient city Teotihuacán in Mexico, Astypalaia, one of the Dodecanese Islands in Greece, Pompeii, or Antarctica.  But if you create an account and join the Mapillary community, you can access the live web map and click on any of the mapped tracks.

Mapillary can serve as an excellent way to help your students get outside, think spatially, use mobile apps, and use geotechnologies.  Why stop at streets?  You or your students could map trails, as I have done while hiking or biking, or  map rivers and lakes from a kayak or canoe.  There is much to be mapped, explored, studied, and enjoyed.  If you’d like extra help in mapping your campus, town, or field trip with Mapillary, send an email to Mapillary and let the team know what you have in mind.  They can help you and your students get started with ideas and tips (and bike mounts, if you need them).

For about 18 months, I have been using Mapillary to map trails and streets.  I used the Mapillary app on my smartphone, generating photographs and locations as I hiked along. One of the trails that I mapped is shown below and also on the global map that everyone in the Mapillary community can access.  I have spoken with the Mapillary staff and salute their efforts.

I look forward to hearing your reactions and how you use this tool.

Mapillary tool for generating and sharing street level photos and maps

Mapillary tool for generating and sharing street level photos and maps.

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New Geocaching, GPS, and Related Geo-Activities

I recently created a presentation on geocaching, GPS, and related geo-activities.  The live webinar from NCGE is here; use the password geocaching to access, and the presentation including all links to the activities and maps is here.  Other geocaching, GPS, and related resources are located in the Esri K12 GIS Organization (despite the name, note that most activities are suitable for higher education as well), under 03:  Blogs, Lessons, & Other Docs, under 05:  GPS Resources.

The objectives of the presentation are to define geocaching and other GPS-related activities, explain reasons for teaching with these, and discuss specific example activities that I and other educators have tested successfully in classrooms from primary to university and adult learning.  Example activities include earthcaching, waymarking, Mapillary, mathematics-driven activities including the calculation of the Earth’s circumference, mass, and volume, GPS drawing, tracking movements over a week’s time, my “Get outside with GPS” set of activities, geocaching events and themes, setting up geocaching courses in ArcGIS Online, and using spatial accuracy and precision as teachable moments.

I also describe other outdoor-related geography apps, such as the creation of storymaps on a phone with Snap2Map, exploring and comparing places on Earth with Field Notes, and citizen science using Collector for ArcGIS.  I also discuss the use of GPS receivers versus GPS apps on smartphones, essential GPS functions for educators, and smartphone GPS apps.  I finish the presentation with activities, books, and other ways to learn more about the subjects presented.

Recording attributes of trees and field notes while marking waypoint with GPS receiver.

Recording attributes of trees and field notes while marking waypoint with GPS receiver.

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Walking on Water? Revisiting Reflections on Resolution and Scale

A few years ago, I walked on the pier at Manitowoc, Wisconsin, and after mapping my route, reflected on issues of resolution of scale in this blog.  After recording my track on my smartphone in an application called RunKeeper, it appeared on the map as though I had been walking on the water!  This, of course, was because the basemap did not show the pier.  Recently, following the annual meeting of the Association of American Geographers, I had the opportunity to retrace my steps and revisit my study.  What has changed in the past 2 1/2 years?  Much.

As shown below, the basemap used by RunKeeper  has vastly improved in that short amount of time.  The pier is now on the map, and note the other difference between the new map and the one from 2012 below it–schools, trails, contour lines, and other features are now available.  A 3-D profile is available now as well.  Why?  The continued improvement of maps and geospatial data from local, regional, federal, and international government agencies plays a role.  We have a plethora of data sources to choose from, as is evident in Dr Karen Payne’s list of geospatial data and the development of Esri’s Living Atlas of the World.  The variety and resolution of base maps in ArcGIS Online continues to expand and improve at an rapid pace.  Equally significant, and some might argue more significant, is the role that crowdsourcing is having on the improvement of maps and services (such as traffic and weather feeds).  In fact, even in this example, note the “improve this map” text that appears in the lower right of the map, allowing everyday fitness app users the ability to submit changes that will be reviewed and added to RunKeeper’s basemap.

What does all of this mean for the educator and student using geospatial technologies? Maps are improving due to efforts by government agencies, nonprofit organizations, academia, private companies, and the ordinary citizen.  Yet, scale and resolution still matter.  Critically thinking about data and where it comes from still matters.  Fieldwork with ordinary apps can serve as an effective teaching technique.  It is indeed an exciting time to be in the field of geotechnologies.

Walking on Water?  Reflections on Resolution and Scale, Part 2

Walking on Water? Reflections on Resolution and Scale, Part 2. My walk on the north pier at Manitowoc, Wisconsin.

The map from 2012 is below.

Map from 2012 of my same route on the pier.

Map from 2012 of my same route on the pier.

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Comparing the Spatial Accuracy of Two Location Apps on a Smartphone in the Field

Building on past field investigations where I studied the spatial accuracy of GPS receivers and smartphone location apps, I recently compared the spatial accuracy of two location apps on a smartphone.   My goals were twofold:  (1) To determine which of two location apps was more spatially accurate in varied terrain and conditions; and (2) To model a field activity that integrates geography, science, and mathematics that students can engage in easily and effectively.

On a hike in the chaparral hills of Southern California, I used my smartphone to collect my tracks using two apps–Motion X GPS and RunKeeper–at the same time.  Once the hike was done, I then exported the track lines and points as GPX files and uploaded them into ArcGIS Online.  The results, shown below, indicate that the two tracks were quite similar; within 1 meter of each other.  I was pleased with the spatial accuracy of both, despite the very steep terrain and considering that the phone was in my pocket most of the time rather than held up high to capture a theoretically stronger set of GPS and cell tower signals.

It was also evident that in this location, on this day, RunKeeper was a bit more spatially accurate, doing better at maintaining the trail switchbacks as I walked rather than cutting them off.   At one switchback, the two tracks were separated by 4.5 meters.  However, just downhill and to the northeast of the image below, Motion X was more accurate for a specific 10 meter stretch of trail.  It must be remembered, however, that these statements “assume” that the satellite image is the best benchmark of spatial accuracy, but it too contains distortions and error.  Furthermore, on a different day and time, with the GPS constellation in a different array, my results could vary.  Varying the speed walked, the time and date, the location app, the location at which the phone is held, the type of phone, and other factors all make for easy-to-implement field investigations that incorporate science, mathematics, geography, and geotechnologies.  And, while outside, you can have rich discussions on land use, land cover, natural processes, access to open space, animal habitat, climate and weather, and much more, as I do here.  The results are easily examined using ArcGIS Online, and students can also create a presentation or a story map in ArcGIS Online to communicate their results.

Give it a try and comment below on the results of your investigations!

Comparing the spatial accuracy of two smartphone location apps in the field

Comparing the spatial accuracy of two smartphone location apps in the field.

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A GPS Track on a Running Track: Reflections on GPS Accuracy

Recently, while at the Applied Geography Conference in Atlanta, I decided to test the spatial accuracy of my smartphone’s GPS in a challenging environment–a rooftop running track.  Although on a roof, the track was surrounded by buildings far taller, and in downtown Atlanta, to boot, a location with many other buildings impeding signals from GPS, wi-fi hotspots, and cell phone towers.  Another challenge was that each lap on the track was only 0.10 miles, and therefore, I would not travel very far across the Earth’s surface.

After an hour of walking, and collecting the track on my smartphone with a fitness app (Runkeeper), I uploaded my track as a GPX file and created a web map of it in ArcGIS Online.  As I expected, the track’s position was compromised by the tall buildings–I only had a view of about half the sky during my time on the roof.  As you can measure for yourself on the map linked above, the track lines formed a band about 15 meters wide, but interestingly, were more spatially precise along the eastern side of the track, where the signal was better, as you can see in my video that I recorded at the same time.

Also, as I have encountered numerous times in the past, a line about 100 meters long stretches to the north.  Rest assured that I did not leap off  the building, but rather, the first point that the GPS app laid down as I opened the doors to walk outside was about a block away.  Then, as I remained outside, the points became more accurate.  When you collect data with students, the more time you have on the point you are collecting, typically the more accurate that point is spatially.

ArcGIS Online map of my rooftop walk

ArcGIS Online map of my rooftop walk.

Another interesting aspect of this study is that if the basemap is changed to satellite imagery, it appears that the track overlaps the tall building to the west.  Try it!  However, a closer investigation reveals that this is a result of the orthocorrection that was done to the imagery; the buildings do not appear from “straight overhead”, but rather, “fall away” to the east.  Turn this into another teachable moment:  Images, like maps, are not perfect. However, both are very useful and we can learn to manage error and imperfection through critical thinking and through the use of geotechnologies.

To dig deeper into issues of GPS track accuracy, see my related post on errors and teachable moments in collecting data, and on comparing the accuracy of GPS receivers and smartphones and mapping field collected data in ArcGIS Online here and here.

Despite these challenges, overall, I was quite pleased with my track’s spatial accuracy, even more so considering that I had the phone in my pocket most of the time I was walking.

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New GPS and Fieldwork Resources Online

A new group in the Esri K12 ArcGIS Online organization invites investigation into fieldwork, GPS, geocaching, and related topics.  The group is open to everyone, and contains a variety of activities, recommendations, videos, and other resources that have been tested with students and educators in a wide variety of settings, disciplines, and levels.

These 32 resources are organized in four sections.  Section A contains core content items such as a GPS primer, ways to map your field data, GPS to GIS videos, waypoints and tracks, and other items to develop skills and content knowledge. Section B focuses on activities, from “Get outside with GPS!” to mapping everyday routes, to setting up citizen science maps, and crowdsourcing your photographs.  Section C’s focus is on geocaching–how to set up a geocaching route, how to effectively use geocaching in instruction, and samples of geocaching courses with creative themes, such as zombies, historical transportation, and more.  Section D digs into technical issues such as comparing the spatial accuracy of GPS data to that collected with smartphones, and teaching about accuracy, precision, and critical thinking with these devices.

Give these resources a try and I invite you to share your results with the community by commenting below.

GPS group in Esri K12 ArcGIS Online Organization

GPS group in Esri K12 ArcGIS Online Organization.

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Fun with GIS 161: Snap2Map

Snap2Map is a slick new app for iOS and Android that will help spread the power available through geotechnology. With it, building a Story Map app is as easy as taking photos on a smartphone or tablet.

Snap2Map relies on a user having an ArcGIS Online Organization login with publishing privileges. After logging in, the user creates a presentation, chooses a basemap, takes photos or chooses existing photos through the device, and annotates them (title and/or description). Snap2Map will use a photo’s location info or allow the user to move it across the street or around the world. Photo sequence also can be adjusted just by dragging with a finger. When complete, Snap2Map sends the points, text, map, and photos into a new feature service in the organization (this is why publishing is a requirement), creates the map, creates the Story Map, and generates a ready-to-go outbound message with the address of the published and shared Story Map. At this point, the user can log into the account via a web browser and make additional modifications to the map, such as adding a GPX track or other context layer.

The beauty of Snap2Map is its simplicity, and the mantra of a bright educator who said “We need to reach in and grab people through their door, and bring them out through ours.” People love taking geolocated photos. It’s an easy extension to bring them to the next level, a story strung together in a geography. After that, the sky is the limit. Fieldwork and even mundane local trips will never be the same again.

With Esri’s ConnectED offer making ArcGIS Online Organization accounts available for free to any US K12 school, for instruction, many educators and kids will have a powerful way to begin working with geotechnology, thanks to Snap2Map.

Charlie Fitzpatrick, Esri Education Manager

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7 Ways to Map Your Field Data

Mapping field data can serve as project-based learning environments that promote environmental, social, and technological fluency, as I wrote about in Earthzine, and as others such as Richard Louv have written about much more eloquently than I.  What are seven easy ways in which you can map field-collected data?  I have recorded a three-part video series (Part 1, Part 2, and Part 3) wherein I describe all seven ways.

These ways include (1) via files and spreadsheets that are stored locally on your computer, (2) via files and spreadsheets that are stored online, (3) via shared web forms, (4) via smartphone apps, including the Collector for ArcGIS app, (5) via editing of ArcGIS Online map notes, (6) via uploading of your geospatial data to ArcGIS Online, and (7) via editable feature services. which enables true citizen science mapping in the sense that you can “crowdsource your fieldwork” as my colleague Charlie Fitzpatrick has written about.

As I hope these videos demonstrate, it is very easy not only to bring in your field-collected data into ArcGIS Online, but to map and analyze it there.  But I can’t give all of the details away:  Watch the videos to find out!

7 Ways to Map Your Field Data, including Crowdsourcing Your Fieldwork

Seven Ways to Map Your Field Data, including Crowdsourcing Your Fieldwork.

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