A 3.320Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE
Editor’s Note: Lying just off the east coast of Africa, the island of Pemba is part of the Zanzibar archipelago of the nation of Tanzania. In 2009, the Zanzibar regional government initiated a project to rehabilitate roughly 45 km (28 miles) of rural roads on Pemba. The $11 million effort was intended to improve safety and maintainability of the island roads. As part of the project, the Swiss company GRG Ingenieure AG was hired to develop horizontal and vertical information on the improvements made to the roadways. In August 2011 GRG assigned surveying engineer Adrian Holzer to perform the field surveys on Pemba. Here is Holzer’s account of the survey.
By late August in Gelterkinden, Switzerland, I have completed the preparations for survey work on Pemba Island. Apparently, the task now at hand is to collect road data to produce a map of the existing roads on Pemba. However, no one can say for sure. Accuracy specifications, fundamental control network, longitudinal and cross sections there are more questions than answers at this point. Moreover, part of the road construction is not even finished. Though there is still a lack of basic information, there are any number of ideas floating around. In my discussions with other surveyors, some approaches have begun to take shape but so many details are lacking. Nevertheless, I am finally able to find a detailed map with general information on the project. So, the preparatory work primarily consists of pleasant anticipation and discussions as well as the procurement of GPS equipment and insurance.
Departure is planned for early September, and I won’t be traveling with a light load. Because of the short time frame, I am carrying my equipment with me as baggage. I have two Trimble® R8 GNSS receivers, a TSC2 controller, my laptop, a base radio for RTK and a generous assortment of cables, chargers and accessories. Have I thought of everything? I will know soon enough.
The first leg of my journey, to Dar es Salaam in Tanzania, proceeds as planned, although the Zurich Cantonal Police decide to take a long look at one of my batteries. When I arrive in Dar es Salaam, Hamisi picks me up, takes me to the hotel and brings me back to the airport the next day for the flight to Pemba. Before my flight’s departure, I sit and wait in a small, familiar room. Twenty years ago I sat in this same room while traveling with my father, who worked as a physician in Tanzania and made regular trips to Zanzibar. Flight delays were common, and I was a very impatient child. My father paid me 100 Schillings for every 15 minutes in which I sat still and was quiet during the seven hours we had to wait. If you asked me today, I would never do that again for so little pay.
This day I make my money in other ways; I save on my excess baggage fees of "only" 50 USD, which I’m invited to "pay" in a back room. The flight to Pemba is a small aircraft and I hope I’m the only one having excess baggage. However, the pilot is British and I’m certain he knows how the wind blows here. Such discrepancies will most likely be included in the mass and balance calculation.
The waiting room empties; almost everybody boards the plane headed to Zanzibar. I no longer fear that my aircraft will be overloaded by excess baggage. Now it’s only me and a friendly woman wearing a burqa waiting for the flight to Pemba.
After I arrive in Pemba, Mr. Idi picks me up and brings me to a resort. I’m the only guest (worker). Here, I begin my work before moving into a house rented for the project. On my first day of work, I try to understand what is actually expected of me. I manage, but only with great effort. We begin exploring some roads, so I can get at least some orientation. With a bit of orientation, my land surveyor psyche begins to feel much better.
After some test measurements to confirm the Trimble equipment has arrived safely and is still in good working order, I set off to the Surveying Department on the adjacent island of Zanzibar to gather fundamental data.
In Zanzibar, I meet the project leader from Switzerland. Together, with a letter of reference from the Ministry of Transport, we go to the office of the Minister for Surveys and Mapping. Unfortunately, he is away. And apparently, no one there knows how to find the data we need. So we are sent from the office on the ground floor to another office on the first floor. From there we go to a second office on the same floor, and then to the third floor. Then back to the very bottom, and again to the second, first, third, first… During all that time, I’m singing to myself…
"I’ve been everywhere, man
I’ve been everywhere, man
Across the deserts bare, man
I’ve breathed the mountain air, man
Of travel I’ve had my share, man
I’ve been everywhere."
Eventually, somewhere on the stairs, we come across a man from Finland. Although he also has no data to share, he provides us with a detailed explanation on how land surveying is organized in Pemba and Zanzibar. Surprisingly, it is quite well developed. As we sometimes encounter back in Switzerland, the problem is that data is collected and stored, but put to no use. I fly back to Pemba that afternoon with this information and a new surveying concept swirling in my head. The following day, I get down to business. Over 40 km of road in total are to be mapped. I am to survey the longitudinal profile and all the civil structures. Distinctive objects such as mosques, power lines or antennas must be measured as well.
An unexpected challenge quickly emerges: eating. There is a large Muslim community on Pemba, and I have arrived in the month of Ramadan. During the day, food is not available. I manage to persuade the cook to give me some rice, bananas and beans for the way. Eating is only possible in the car; anything else would be considered impolite. While travelling, it’s nearly impossible to buy anything. I see the effects of fasting also taking hold of my driver–over the course of the afternoon, his driving becomes ever more aggressive and he complains of a headache.
Muslims on Pemba pray five times a day. For the noon prayer, I plan my work so that we are somewhere in the proximity of a mosque. This way, my driver may perform his prayer while I continue my work, since time is short. One day following such a noon prayer, the statement I have come to adore so much slipped from the mouth of my local driver: "We pray, you work." As soon as the sun disappears everyone can finally eat something together. Well, almost together– men and women must eat separately.
And so I measure day by day, road section by road section. I must manage the equipment in the high temperatures and dust. I am using a low-power radio for my RTK base station and frequently move the base station as I progress on the survey. When working in forested areas, I often change position, lifting the receiver, looking towards the sky and waiting for a signal. The people watching me must be thinking, Musungu (white man) has definitely lost his mind, speaking to the sky with a grey-white bowl. Or so I thought, but I was mistaken. I converse with the spectators and explain to them what I’m doing. I find that most of them know very well, in fact, what a GPS receiver is. They even ask me precise questions regarding the accuracy of the instrument.
On Pemba Island, there are four or five major cellular signal towers. They are fenced and guarded; the guardhouse is a straw hut next to the tower. Since my job is also to measure antennas, I quickly march with purpose towards the target. Unfortun
ately the initialization is lost and will likely once again take time to re-establish. As usual, a happy group of children following me shakes the guard out of his sleep with their chattering. Perhaps for the first time in the last five years, the guard sees that his moment has come. Pompously he stands in front of me and snarls, “I am the Special Security. What are you doing here?” I explain to him that I am the Special Surveyor and have to survey this antenna. “Do you have an official letter?” (An official letter with a seal would probably open any doors here….) “No, I don’t have one.” So he turns on his cell phone to call his boss. Finally, my driver takes over and explains to the superior at the other end of the line what we are doing here. Once the authorization is granted, the guard retreats into his hut, rather disappointed. As the saying goes, “Europeans have watches, Africans have time.” I must wait for my driver time after time. I’m not the epitome of punctuality, but waiting for up to an hour makes me a bit impatient given my tight time budget. I’ve adopted the term “Musungu time” from my project leader Andreas Beusch. My driver finds it so amusing that from now on, he runs like a Swiss clock. Lately it’s me who has to apologize for arriving late every morning. Obviously, I’m beginning to catch the slower African flow.
In order to put the results of my own survey into the national system, I still need to measure some permanently marked control points. Lo and behold, these points are in fact available and in very good condition. After I promise to present an official letter with a seal, the local authorities hesitantly provide me with a list of coordinates and sketches with proper point documentation. However, reading the sketches is not an easy task. One description states that a point I am looking for is situated "16 m from the palm tree and 32 m from the rootstock." Unfortunately, I’ve no way to find out which palm tree or which rootstock on this island they refer to.
Clearly, I need some local expertise. Once the financial details are worked out, a local surveyor is placed at my disposal. He navigates to the control points as if he had been there just yesterday. At least, he remembers from which palm tree the measurement has to be started. In the beginning, our conversation remains rather cool. But once he realizes that even a Musungu feels a certain joy and fascination when he finds a control point, the dam really breaks. After having collected – in my opinion – enough control points, which are evenly dispersed over the whole project area, my counterpart explains to me that he knows of more control points which are in very beautiful settings. He says he knows of one extraordinary point, which he absolutely has to show me. Convinced by the gleam in his eye, I agree to go along and see the other points, since the day is over anyway. They were indeed exceptionally beautiful places.
The following day, my pleasant colleague is back again. I explain to him that I’ve paid him for only one day and that I can now work alone. He doesn’t care and wants to come along with me. Now numbering three, we go to set up the first base station. My counterpart assists me in a very professional manner. He says he learned the business in Dar es Salaam. Towards evening, we travel to his village. After leaving the car, he invites me to his home to take some souvenir pictures. Like me, he will show these pictures back home and tell everyone the story of our adventure.
Towards the end of the project, Roman Meyer, a friend from my university days, comes over from Rwanda for a visit. Before we continue on to Zanzibar, we carry out the final measurements together. I’m glad for the help and companionship–it’s nice when you don’t have to drink your beer alone after work.
By late September I have collected all the data I need. The information includes roughly 4,000 individual points on and near roughly 40 km (25 mi) of Pemba roads. I have captured centerlines: culverts, ditches and bridges; electric facilities, radio and cellular antennas; and stone gabions. I’ve also collected the location of the mosques along the roads.
With the work complete, Roman and I fly to Zanzibar together. There we spend a few survey-free days. We visit Stone Town, a lively city with bars and restaurants, a colorful marketplace with countless merchants, and stately old buildings dating back to the British Empire. The celebration in town marking the end of Ramadan is especially impressive. Everybody has dug out their nicest clothing to wear. The delicious smell of the festive food is tantalizing. The vendors are selling everything one can find under the sea as well as meat, vegetables, flat bread, fruits and much more. We can finally fill our stomachs to bursting and enjoy the colorful scenery before we go home.
Dipl.-Ing. Adrian Holzer is a geoinformatics and surveying engineer with GRG Ingenieure AG in Switzerland.
A 3.320Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE