Exploring Zanzibar with Mapillary: Pt 2 - The End of the Road

After the labyrinth of Stone Town’s alleys and a ship wreck on the west coast, our story heads east. This blog post is a continuation of Pt 1 - The Chief Officers’ Logbook. If you haven’t read part 1 of our adventures in Zanzibar, start there. If you have, welcome to part 2!

If you missed it, read Part 1 of this adventure in last week's blog post.

On Sunday morning we had set up a small Mapillary command center in the back of Zanzibar Coffee House. Our plan was to get some work done and then head east to the beautiful beaches of Paje and surrounds. As a hotspot for other geo-folk exploring the island after FOSS4G, we met some familiar faces there. It turned out the entertaining Chad Blevins was heading to Paje as well for some kite-surfing, and being short of a ride we were happy to sign him up as a fellow passenger. After getting the cameras set up again (and getting a quick battery jump from a dozen taxi drivers standing by, don’t forget to turn those lights off overnight), we hit the road again.

zanzibar-two-1 Roadside stands were selling fresh cut coconuts to keep us hydrated on our journey

The route to Paje featured some diverse landscapes, as well as opportunities for quick roadside refreshments in the form of fresh coconut water straight from the shell. We quickly saw a transition from urban Zanzibar City to dense forest and rural settlements, as well as agricultural land and livestock pasture.

At around 1pm we rolled into Paje with visions of flying along the water behind a kite in the front of our minds. Upon arrival at the kite school however, our dreams were dashed. It seems learning to kite surf in 2 hours is a rather grand ambition. We pondered this prospect over lunch. Chad the brave was up for the challenge, but for us two adventurers, the road beckoned. We jumped back in the car and headed north along the eastern portion of the island. Each kilometer presented new imagery for the Mapillary archives.

Not too far north of Paje you will encounter the “The Rock” where some enterprising individuals have constructed a restaurant atop a rather large (you guessed it) rock. During high-tide one must take a small boat out to The Rock’s entrance. During low tide you can rock scramble your way over. After a quick refreshment and a few too many fellow tourists, we jumped backed in the trusty Toyota.

Our Sunday journey took us past Pingwe and to the end of the road. By this time the sun was leaving long shadows, so we decided to park the car and make the most of the daylight that remained. This involved a pleasant swim in the warm Indian ocean, escaping from mud crabs, and wading through the mangrove forests as salamanders scuttled by. A glorious sun set brought an end to a fine weekend. The working week was to begin, and it proved equally interesting.

zanzibar-2-2 Mangrove trees on a quiet stretch of beach

Monday began with our usual morning search - caffeine and Wi-Fi. Having been focused on FOSS4G the week prior and mapping over the weekend, each of us had a mountain of tasks to start the week off–9:00 am Monday reminders and inboxes of an unhealthy size needed to be attended to.

A few espresso and tonics later (yes that’s a thing), it was time for us to meet with Stone Town’s Open Cities Africa team. Yves was also in attendance as well as Spatial Collective–a geospatial consultancy based in Kenya. During the meeting we walked through some of the challenges we had been facing the last few days in our efforts to map Stone Town. The meeting was also a chance for a quick Mapillary refresher with a photo walk to capture imagery around Forodhani Park. We parted ways with the intention of visiting State University of Zanzibar (SUZA) the following day.

zanzibar-2-3 Ed discusses how to integrate Mapillary into mapping workflows

Tuesday we hit the ground with cameras rolling right away. With SUZA our ultimate destination, we thought we’d make use of the rental car and capture some of the routes on the southern parts of the island. There were still many areas of Stone Town without coverage, and as we headed east we decided to explore the neighbourhood of Mombassa. OSM revealed a vast network of residential roads, but we had no idea as to their navigability. Thus began a process of trial and error, venturing away from the main roads and deeper into the suburbs. On a number of occasions we ended up down a narrow pedestrian only path, at someone’s house or in a school yard. Eventually we made our way back to asphalt, but the drive illustrated the importance of proper classification of roads in OSM. The classification should also be country specific, considering the use of the road, not just the surface type. With street-level imagery of these suburbs, we can start to update the classification for these roads to better reflect which ones are navigable by four-wheeled vehicles.

zanzibar-2-4 Updating the road classifications with our latest Mapillary imagery as reference

After leaving Mombassa, we continued our journey east, eventually making our way to the stunning beaches south of Jambiani. After a quick swim in Zanzibar’s warm waters, we set up the cameras for a quick video update on our time in Zanzibar. It was then time to head to SUZA for an afternoon of work.

On Wednesday we made our way back to SUZA for a full day of Mapillary training with computer science and geography students. SUZA has been a key player in the Zanzibar Mapping Initiative (ZMI), helping to map both the main island of Unguja and Pemba island with drones. As a consequence, high resolution aerial imagery is available for government decision making and OpenStreetMap. The students were thus quick to understand Mapillary, how street-level imagery can be used to derive map data, and how to upload using mapillary_tools. We left behind two GoPro cameras so that students can continue our efforts to map the island.

Wednesday was very much a two way knowledge exchange however, with the students giving us a hands on go at drone mapping– definitely a highlight of our a trip. After a long day, we jumped back in the car. The students of SUZA decided to jump in as well and we had a great time heading back to Stone Town, taking many wrong turns along the way.

zanzibar-2-5 High resolution imagery from ZMI’s drone mapping is extremely helpful when editing OSM

Our last full day in Zanzibar was spent at the Maru Maru, getting as much work done as possible in anticipation of a weeks-long vacation in Ethiopia. That same evening, we had the opportunity to meet with the Department of Urban and Rural Planning in Zanzibar to discuss how they could use street-level imagery in their day to day work. Alongside the common use case of parcel management, it was interesting to hear how useful time-travel would be for them, comparing how an area looks at two different points in time. An amusing example the director brought up concerned the heavy, ornate doors that adorn many buildings in Stone Town. Some of the doors are hundreds of years old and consequently very valuable. The director recounted how thieves have been known to steal the heavy doors in the middle of the night, replacing them with knock offs in the hope no one would notice. While this is not a use case Mapillary ever had in mind, it was fascinating to see the unique applications that come to mind in different parts of the world.

Zanzibar was a whirlwind trip and we thoroughly enjoyed the time we spent there. We hope the imagery we collected will prove useful for Tanzania. Most importantly, we’re looking forward to future mapping efforts and will be following closely as drone imagery and street-level imagery are used to create one of the most accurate maps in Africa.

/Edoardo Neerhut, Strategic Partnerships Manager

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