Clew: Navigation App Review

Clew is an iOS app that records a user's path and then guides the user back to his starting point. Clew was created to help travelers who are visually impaired to remember a location such as returning to a seat in a room. Designed to work indoors, Clew uses augmented reality to record landmarks along your route. Clew is available for free in the App Store.

How to Use Clew

Hold your phone upright in front of you with the camera pointing straight ahead. Press the record button, then walk your route. In the Clew video, the developers recommend that the user first travel and record the route using human guide. Press Stop Recording at the end of the route. When ready to return, Press Return. Wait for Clew to convert the information. Clew will then provide verbal, haptic and visual feedback as the user reverses his route. Visually, the screen shows an image of the next route segment with a red pin indicating where to go. (Clew calls the pin 'Crumb Indicator'.) If the user veers off the path, the red pin disappears off the edge of the screen. When walking along the desired path, a clicking sound is heard; the clicking sound stops to indicate when the traveler has veered. A whistle tone indicates a turn; the app also verbally announces which way to turn. The route is available until the app is closed using the app switcher. According to the website, Clew works best with short routes.

The developers of Clew are asking users to provide feedback.

The video below provides information about Clew.

Editor Comments

NOTE: Clew is used in addition to a cane or dog guide; Clew does not provide any protection for obstacles/surface changes and is intended only to give reverse route navigation information!

The app is simple to use, with only one or two buttons on the bottom center of the screen; these buttons appear as needed. Example: The Start Recording button appears initially which is replaced by the Stop Recording button. After the recording is stopped, the Navigation and Pause buttons appear.

I recorded a route to a bathroom and then used Clew to return to my seat in another room. This route included hallways, multiple turns and stairs. In another route, I recorded using Clew to go from a desk in a classroom, traveling in several hallways and turns, traveling outside and going down a spiral staircase. Both of these routes were in uncluttered and quiet hallways.

NOTE: A route can only be traveled one time. When I went back to the restroom and wanted to reverse the route back to my seat the second time, Clew indicated that I had "arrived" at the restroom and I did not have the option of reversing the route back to my seat again.

For best results, use Clew in uncluttered environments; moving pedestrians may impact Clue's accuracy. When recording your route, make good 45 degree turns. Accuracy may improve when you exaggerate your turn by slowing down slightly and making a military-style 45 degree turn. Clew is most accurate when traveling in straight lines and 45 degree turns. Moving in a straight diagonal line through open space worked well during one route; however, when transitioning from a wide hallway to a narrow hallway, Clew did not indicate where the narrow hallway was (and without good O&M skills, I would have run into the wall!) When ascending a spiral staircase, Clew periodically announced to turn right and go upstairs.

Clew's website shows shows a Customize Settings Screen which allows users to choose options such as unit of measurement, Crumb color, toggle on/off features, etc. However, when reviewing the app, I could not find the customized settings page.

O&M Perspective

As an Orientation and Mobility Specialist, my goal is to teach students how to use environmental clues and landmarks, mental mapping skills, and other standard O&M skills. Once learned, these skills can be transferred to any environment. Ideally, students should have strong O&M skills and should not need the assistance of an app to reverse a route. However, every traveler is unique and there may be some travelers - especially those who are in the process of learning good O&M skills - who may benefit from Clew to help retrace steps. I would caution users and O&Ms that this app should be used as a training tool and travelers should not become dependent on it.

As a training tool, Clew does a wonderful job of breaking a route into segments. As an O&M working predominantly with preschool and K12 students, I intentionally teach students to break a route into chunks. Students often are overwhelmed with the amount of sounds and landmarks in the environment and are easily distracted or perseverate by things along a route. This app does a great job of filtering out the extra information and focusing on the truly important pieces of the route - the next turn or the next major landmark such as traveling up/down stairs. When working with O&M students, I use the term "next decision-making landmark" paired with what he is to do at that landmark; this helps the students to focus on the big picture and to not get lost in all the details! Typically, the "next decision-making landmark" is an intersection and the student needs to name which way he is to turn. If the next decision-making landmark is a staircase, then the student has to also name whether he is going to ascend or descend those stairs. 

I am already buzzing with ideas on how to use Clew as a tool to teach breaking routes into segments and how to focus on the next decision-making landmark. I would like to be able to turn off the announcements and have just the whistle tone indicating a turn (without giving information about which way to turn). This would be a good "training wheels step" for users who might need some prompt but who should know the general direction he needs to travel and should be anticipating his route.I can also see how Clew would be a fun tool to reinforce reverse route concepts! How will YOU use Clew?


  • The ability to save, name and use a recorded route again. (Currently a Clew route can only be traveled one time.)
  • The ability to save multiple routes.
  • The ability to label (name) the hallways/intersections, as this will help establish a mental map.
  • Ability for Clew to announce the next decision-making landmark as the traveler begins that segment of the route, so that the traveler can set in his mind what he is looking for (this might be a settings feature that can be turned on/off).


Posted by pruvoloApr 12, 2019

Beta version of Clew available with support for route saving!   Hi Folks,   Based on feedback from many early adopters of Clew (thank you to all!), we are pleased to announce the release of a beta version of Clew that incorporates many of the suggestions we’ve heard from the community.   The short version of this notice is that you can download a beta version of Clew through Apple’s Test Flight using the link below.  Makes sure to read the new help file as a number of things about Clew have changed significantly (or keep reading). Here is the link: to the beta.   Here are the major changes:   (1) By far the most requested feature for Clew is route saving.  Clew now supports saving routes.  Detailed information on how to save routes is given through the in-app “Help” menu.  At a high-level, to save a route you must first anchor your route by positioning your phone in a location and orientation that you can return to at a later time (unassisted) and then activating the “Create Landmark” button.  One can think of this position as a “landmark” in much the same way as landmark’s are thought of in orientation and mobility courses.  It is a place that helps you orient and position yourself within an environment.  Good choices for landmarks are vertical surfaces that are easy to find such as door frames, walls, or windows.   To reload the route, you can return to this same location, position your phone as you did when you created the route, and the app will start providing feedback.  Many times when navigating along a route, the app will be able to further refine your alignment to the saved route by registering the current environment’s visual features to those that it saw when the route was initially recorded.  Since this automatic registration does not happen every time, it is necessary to use a landmark in addition to automatic alignment.   (2) Support for bi-directional routes.  Initial versions of Clew only allowed for navigating your route in reverse.  Many folks requested the ability to navigate the route in the forward or reverse direction.  Support for this has been added.  Importantly, we have observed that route guidance is actually more accurate in the forward direction than the reverse direction (especially when loading saved routes).   (3) Enhancements for users with low vision.  We have enlarged text and button sizes in many parts of the UI (although, many more changes are in the works to do a better job of supporting users with low vision.).  We have also allowed for speech feedback that is not tied to VoiceOver.  This means that if you have enabled the voice feedback option, the app will speak directions to you even if you are not using VoiceOver.   (4) Easier to use pause and create landmark procedure.  When pausing a route in previous versions of Clew, the user was instructed to place the phone against a vertical surface with the camera facing out and the screen facing the wall.  In this configuration the user confirmed that the phone was in the correct position using the volume button (since the screen is not physically accessible in this configuration).  We have changed this procedure.  Now, alignment is done by pressing the top edge of the phone flush with the vertical surface and the screen facing up.  In this configuration, the phone’s position can be confirmed with an onscreen button (which is much more standard).  We have also found that this alignment procedure seems to be a bit more accurate than the previous one and is certainly easier to do and comes with less risk of dropping one’s phone.   (5) Sound feedback volume is now tied to the phone’s volume level even if the mute / vibrate switch is activated.  This change was made in response to some users who were not hearing sound feedback and had a tough time understanding what was causing this.  The reason in many cases was that the mute / vibrate switch was activated.  The new behavior is that if the sound feedback option is activated in the app settings, the app will play sounds (provided the phone’s volume is non-zero).   (6) More transparent communication of tracking errors.  The previous version of Clew hid most of the potential errors with motion tracking from the user.  Now the app communicates errors such as in cases where there are poor visual features in you environment or if the phone is being moved too quickly.   (7) Dropped support for iOS 11.  The new route saving feature requires iOS 12 (or higher) to work as well as possible.  While a much more basic version of route saving would have been possible with iOS 11, we didn’t feel that it would work well enough to justify implementing it.   We would love feedback on these new features before we release this as an official app update.  You can provide feedback through TestFlight e-mail contact or to either of these e-mail addresses ( or   As a final note, while the changes above certainly address some of the feedback we’ve gotten from you all, there are still many things we have not had a chance to do (one notable thing is support for other languages).  Please trust us that we are working on these aspects of the app and look forward to continually improving Clew for the community.   Known bugs: (1) The display of metric units got a bit mangled in the current beta build.  It is still apparent what is being communicated, but a space was accidentally left out of the text that VoiceOver reads.  This is fixed, but I am waiting to upload a new beta build for when we have collected and responded to more feedback from the community.   Again, the link to the beta version that can be downloaded through TestFlight is here:   All the best, and we really appreciate the feedback we have gotten from the community to help us improve Clew, Paul