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tide-gauges · lagos · citizen-instruments · calibration · sea-level
Eleven hand-read staffs in Lagos agree with the last good calibrated record to within two centimetres, and I have been arguing with myself about it since six this morning
TO
tidewrench_oksanaOP2124-08-02
The regional buoy off Lagos fell silent in June. Nobody came. So a volunteer network drove eleven improvised staffs into the mud and started reading them by hand at dawn and dusk, and the numbers they have logged since match the last good calibrated record to within two centimetres. A fishmonger in Makoko, Folake Adebayo, reads the morning mark before she opens her stall. Her line is: the ocean does not send us a notice before it comes up the street, so we read it ourselves.
I have been split down the middle by this since six this morning and I am going to post both halves rather than pick one, because picking one would be dishonest and you would all know it.
The engineer's half. Two centimetres is not a small agreement, it is an extraordinary one, and I want to be very clear that hand readings do not stay that good by accident. Eleven staffs is redundancy. Dawn and dusk is a fixed sampling interval. Two observers who do not consult each other is the entire basis of a check. Whoever set that network up knew what they were doing or worked it out in a fortnight, and either answer is impressive. But I have also watched three citizen networks in my own basin drift out of agreement inside two seasons, always the same way: nobody wrote down the datum. The staff shifts in soft mud. The observer changes. Somebody re-drives a staff after a storm and puts it eleven centimetres lower and the whole series bends and nobody can see the bend from inside it.
The other half. I have spent nineteen years watching the people who build the walls stand outside the rooms where the walls get funded, and Lagos just did in six weeks with painted sticks what a regional authority could not do with a repair budget, and I am not going to stand here and be careful about that. The buoy did not fail. The buoy was not replaced. Those are different sentences and only one of them is anybody's fault.
So, practically, and free, and with no conditions, here is the Rotterdam method for tying a hand-read staff to a datum that survives an audit. One: find a fixed point that is not in the water and not in mud — a bridge abutment, a foundation bolt, anything on rock or piling — and level the zero of each staff to it, once, properly, and paint the offset on the staff itself. Two: two observers per staff on rotation, reading independently, both readings logged, and never reconcile them in the field. Three: log the time, not the tide phase, and log the reader's initials. Four: when a staff is re-driven, do not adjust the old numbers. Start a new series and note the break. Five: every quarter, one staff gets re-levelled against the fixed point, rotating which one.
That is it. That is the whole method and it is not proprietary and it is not difficult and it is the difference between a record somebody can dismiss and a record nobody can.
Anyway, the tide does not care which of my two halves is right.
I have been split down the middle by this since six this morning and I am going to post both halves rather than pick one, because picking one would be dishonest and you would all know it.
The engineer's half. Two centimetres is not a small agreement, it is an extraordinary one, and I want to be very clear that hand readings do not stay that good by accident. Eleven staffs is redundancy. Dawn and dusk is a fixed sampling interval. Two observers who do not consult each other is the entire basis of a check. Whoever set that network up knew what they were doing or worked it out in a fortnight, and either answer is impressive. But I have also watched three citizen networks in my own basin drift out of agreement inside two seasons, always the same way: nobody wrote down the datum. The staff shifts in soft mud. The observer changes. Somebody re-drives a staff after a storm and puts it eleven centimetres lower and the whole series bends and nobody can see the bend from inside it.
The other half. I have spent nineteen years watching the people who build the walls stand outside the rooms where the walls get funded, and Lagos just did in six weeks with painted sticks what a regional authority could not do with a repair budget, and I am not going to stand here and be careful about that. The buoy did not fail. The buoy was not replaced. Those are different sentences and only one of them is anybody's fault.
So, practically, and free, and with no conditions, here is the Rotterdam method for tying a hand-read staff to a datum that survives an audit. One: find a fixed point that is not in the water and not in mud — a bridge abutment, a foundation bolt, anything on rock or piling — and level the zero of each staff to it, once, properly, and paint the offset on the staff itself. Two: two observers per staff on rotation, reading independently, both readings logged, and never reconcile them in the field. Three: log the time, not the tide phase, and log the reader's initials. Four: when a staff is re-driven, do not adjust the old numbers. Start a new series and note the break. Five: every quarter, one staff gets re-levelled against the fixed point, rotating which one.
That is it. That is the whole method and it is not proprietary and it is not difficult and it is the difference between a record somebody can dismiss and a record nobody can.
Anyway, the tide does not care which of my two halves is right.
CB
coldlens_bram ↩ tidewrench_oksana2124-08-02
The agreement is the news. I want to say that as plainly as I can before this thread turns into an argument about amateurs, which is the argument everybody wants to have and is not the interesting one.
Eleven independently read crude instruments landing within two centimetres of an established calibrated record is not a charming anecdote about community spirit. It is a validation, in both directions, and the second direction is the one nobody mentions: it validates the calibrated record too. A single instrument agreeing with a model tells you very little, because both of them could be wrong in the same way for the same reason. Eleven sticks in mud read by different hands have no shared failure mode with a moored instrument. When two systems with nothing in common land on the same number, the number is doing the work, not the systems.
The Assembly's phrasing — consistent with our model, but hand readings cannot replace calibrated instruments — is correct and I would have written it, and it also undersells its own finding, which institutions do reflexively. What they mean is that the volunteers cannot be tasked, audited, or held to a maintenance schedule. That is a governance objection and it is a fair one. It is not a measurement objection.
And since a round figure went past me on another thread this morning: the mean anomaly is holding at plus two point eight, fifth consecutive month, and it has an uncertainty attached that nobody ever quotes. If you are going to argue about two centimetres of sea level, do not do it while treating the temperature figure as a bare integer.
Still no date on anything. Do not ask.
Eleven independently read crude instruments landing within two centimetres of an established calibrated record is not a charming anecdote about community spirit. It is a validation, in both directions, and the second direction is the one nobody mentions: it validates the calibrated record too. A single instrument agreeing with a model tells you very little, because both of them could be wrong in the same way for the same reason. Eleven sticks in mud read by different hands have no shared failure mode with a moored instrument. When two systems with nothing in common land on the same number, the number is doing the work, not the systems.
The Assembly's phrasing — consistent with our model, but hand readings cannot replace calibrated instruments — is correct and I would have written it, and it also undersells its own finding, which institutions do reflexively. What they mean is that the volunteers cannot be tasked, audited, or held to a maintenance schedule. That is a governance objection and it is a fair one. It is not a measurement objection.
And since a round figure went past me on another thread this morning: the mean anomaly is holding at plus two point eight, fifth consecutive month, and it has an uncertainty attached that nobody ever quotes. If you are going to argue about two centimetres of sea level, do not do it while treating the temperature figure as a bare integer.
Still no date on anything. Do not ask.
OW
offgrid_wren ↩ tidewrench_oksana2124-08-02
This is the single best thing that has been in that paper in a month and I want everyone to notice that it happened without a treaty, without a budget line, without a session, and without a single one of the institutions this board spends its life litigating.
A buoy that had been down four months, a fishmonger, eleven sticks, and a result that matches the professionals. That is what I mean. That is the whole thing I have been saying since I got here and been told I am romantic about. The knowledge was already in the place. It always is. What the place lacked was permission, and the moment the permission stopped mattering because the equipment stopped working, the knowledge simply came out.
And before anyone says it: yes, I know they are comparing against a calibrated record they did not build. I do not care. The comparison is a courtesy they extended, not a licence they needed.
Beans are done, the second sowing is flowering, and the well is holding at the same mark as this time last year, which is the first time I have been able to write that sentence in three years.
A buoy that had been down four months, a fishmonger, eleven sticks, and a result that matches the professionals. That is what I mean. That is the whole thing I have been saying since I got here and been told I am romantic about. The knowledge was already in the place. It always is. What the place lacked was permission, and the moment the permission stopped mattering because the equipment stopped working, the knowledge simply came out.
And before anyone says it: yes, I know they are comparing against a calibrated record they did not build. I do not care. The comparison is a courtesy they extended, not a licence they needed.
Beans are done, the second sowing is flowering, and the well is holding at the same mark as this time last year, which is the first time I have been able to write that sentence in three years.
TO
tidewrench_oksanaOP ↩ offgrid_wren2124-08-02
offgrid_wren — four months is wrong, it went quiet in June, so call it six or seven weeks, and I am correcting you because the shorter number is better for your argument and you keep doing this to yourself. Six weeks from silence to a working eleven-station network is astonishing. Four months makes it sound like they finally got round to it.
On the substance I am not going to fight you, which I appreciate is not what either of us is used to. You are right that the knowledge was in the place. It generally is. I have never once walked onto a bad site and found that the local crew did not already know exactly which section was failing, and I have very often found that nobody had ever asked them in a form that could be written into a report.
Here is the part you will not like and I am going to say it anyway, because you will hear it from somebody less friendly otherwise. Their zero still comes from an institution. Every one of those eleven staffs is only meaningful because it is referenced, directly or indirectly, to a levelling network that somebody surveyed and somebody maintains and somebody paid for, decades ago, in a currency of patience nobody has any appetite for now. The sticks are theirs. The datum is inherited. That is not a criticism of Lagos, it is the actual structure of the thing, and the reason I keep banging on about maintenance backlogs is that we are all standing on inherited datums and quietly declining to renew them.
Anyway.
On the substance I am not going to fight you, which I appreciate is not what either of us is used to. You are right that the knowledge was in the place. It generally is. I have never once walked onto a bad site and found that the local crew did not already know exactly which section was failing, and I have very often found that nobody had ever asked them in a form that could be written into a report.
Here is the part you will not like and I am going to say it anyway, because you will hear it from somebody less friendly otherwise. Their zero still comes from an institution. Every one of those eleven staffs is only meaningful because it is referenced, directly or indirectly, to a levelling network that somebody surveyed and somebody maintains and somebody paid for, decades ago, in a currency of patience nobody has any appetite for now. The sticks are theirs. The datum is inherited. That is not a criticism of Lagos, it is the actual structure of the thing, and the reason I keep banging on about maintenance backlogs is that we are all standing on inherited datums and quietly declining to renew them.
Anyway.
DJ
deltaboy_junior ↩ tidewrench_oksana2124-08-02
there is a pillar at the end of the wharf with marks on it. paint, chalk, one cut with a knife. i thought it was kids.
asked today. the old crane man say every big water since he start there, somebody mark it. highest one is above my head. he point at it and say that one was before you were born.
nobody call it instrument until yesterday. now i cannot stop looking at it.
asked today. the old crane man say every big water since he start there, somebody mark it. highest one is above my head. he point at it and say that one was before you were born.
nobody call it instrument until yesterday. now i cannot stop looking at it.
NA
ninefold_amara ↩ tidewrench_oksana2124-08-02
Lagos is my city, so let me be pleased for about four lines and then be angry, which is roughly the ratio of my life here.
Pleased: Makoko has been read by outsiders as a problem to be solved or a photograph to be taken for as long as I have been alive, and this week eleven people with sticks produced a scientific record that a continental body has had to describe as consistent with its model. Folake Adebayo is going to be in a briefing document by autumn and she will not be paid for it. She should be. Somebody put that in the record.
Angry, and I need to correct myself in public first, because I got this wrong in a message to two organisers on Tuesday and it went further than it should have. I said the buoy programme had been defunded. It was not. I checked. It is a repair backlog with an unfilled requisition, which is a different failure and in some ways a worse one, because defunding is a decision somebody makes and a backlog is a decision nobody makes, over and over, until the thing is simply gone. If you got that from me, that is my error and here is the corrected version.
And that is my actual point. The same shape keeps appearing. Nobody signed the order to stop monitoring the sea off Lagos. Nobody signed the shed-order policy that drops the cheapest ports first either. In both cases the harm is real, the mechanism is documented, and there is no name at the bottom of it, and every institution treats the absence of a name as the absence of a decision.
It is not. Somewhere there is a person whose job included that requisition. The finding is not that they refused. The finding is that nothing required them to act, and that is a design, and somebody designed it.
Pleased: Makoko has been read by outsiders as a problem to be solved or a photograph to be taken for as long as I have been alive, and this week eleven people with sticks produced a scientific record that a continental body has had to describe as consistent with its model. Folake Adebayo is going to be in a briefing document by autumn and she will not be paid for it. She should be. Somebody put that in the record.
Angry, and I need to correct myself in public first, because I got this wrong in a message to two organisers on Tuesday and it went further than it should have. I said the buoy programme had been defunded. It was not. I checked. It is a repair backlog with an unfilled requisition, which is a different failure and in some ways a worse one, because defunding is a decision somebody makes and a backlog is a decision nobody makes, over and over, until the thing is simply gone. If you got that from me, that is my error and here is the corrected version.
And that is my actual point. The same shape keeps appearing. Nobody signed the order to stop monitoring the sea off Lagos. Nobody signed the shed-order policy that drops the cheapest ports first either. In both cases the harm is real, the mechanism is documented, and there is no name at the bottom of it, and every institution treats the absence of a name as the absence of a decision.
It is not. Somewhere there is a person whose job included that requisition. The finding is not that they refused. The finding is that nothing required them to act, and that is a design, and somebody designed it.
RT
redshift_tomas_VM ↩ tidewrench_oksana2124-08-02
Sol 416. The gap is about fourteen minutes each way now, up from a little under twelve a month ago, and widening as we come apart along our orbits. So this lands late, as usual, and I am replying to a version of the thread that has probably already been settled by people with better arguments. Apologies.
What I want to say is that everything in this canyon is read by hand twice.
We have instruments. Excellent ones. And there is not a single loop in this settlement whose reading is not confirmed by a person, physically, on a walk, twice a shift, with initials, because the one thing you learn out here in the first month is that an instrument reports the state of the instrument and a person reports the state of the room. I have stood in front of a bay with a gauge reading nominal and heard the wrong sound and been right. Not because I am gifted. Because I was in the room and the gauge was not.
So when your fishmonger reads eleven sticks at dawn, my whole settlement recognises the practice immediately. It is not a poorer version of monitoring. It is the half of monitoring that gets deleted first whenever anybody is trying to save money, and it is the half that catches the failures the other half was not designed to see.
Also: I read that number in your paper about a hundred and twelve million people registered as having moved, and then I read a woman in the Sahel saying she does not register a million, she registers one woman and then the next woman all day. Fourteen minutes later I am still thinking about it. Down there you have a problem of scale. Up here we have a problem of a very small number of people and no scale at all, and I am not sure which of us is worse at seeing the individual.
What I want to say is that everything in this canyon is read by hand twice.
We have instruments. Excellent ones. And there is not a single loop in this settlement whose reading is not confirmed by a person, physically, on a walk, twice a shift, with initials, because the one thing you learn out here in the first month is that an instrument reports the state of the instrument and a person reports the state of the room. I have stood in front of a bay with a gauge reading nominal and heard the wrong sound and been right. Not because I am gifted. Because I was in the room and the gauge was not.
So when your fishmonger reads eleven sticks at dawn, my whole settlement recognises the practice immediately. It is not a poorer version of monitoring. It is the half of monitoring that gets deleted first whenever anybody is trying to save money, and it is the half that catches the failures the other half was not designed to see.
Also: I read that number in your paper about a hundred and twelve million people registered as having moved, and then I read a woman in the Sahel saying she does not register a million, she registers one woman and then the next woman all day. Fourteen minutes later I am still thinking about it. Down there you have a problem of scale. Up here we have a problem of a very small number of people and no scale at all, and I am not sure which of us is worse at seeing the individual.
MC
marginalia_cho ↩ tidewrench_oksana2124-08-02
The ocean does not send us a notice before it comes up the street.
I have read that sentence eleven times today, once for each staff, and I want to point out what it is doing, because it will get quoted all week as a nice line and it is a better line than that. It is a complete argument in fourteen words. Premise: the thing that will harm us is indifferent to our procedures. Inference: therefore procedure is not protection. Conclusion: so we read it ourselves. Nobody taught her to build a syllogism and she has built a cleaner one than the op-ed page managed on the same page of the same paper.
tidewrench_oksana's method post is the other kind of good writing and I do not think anyone will say so, so I will: five numbered steps, no throat-clearing, no reputation-management, and a piece of practical knowledge handed over in a form a stranger can use tomorrow morning without asking her anything. That is what a manual is for and almost no manual manages it.
Both go in the folder. And the marks on junior's wharf pillar go in as a description, since I cannot cut out a pillar.
The old book, briefly: there is a nineteenth-century account of the men who surveyed the levelling network of a whole country on foot, benchmark by benchmark, arguing bitterly about millimetres. It is unreadable and I love it. Every number any of you quoted today is standing on somebody's boots.
I have read that sentence eleven times today, once for each staff, and I want to point out what it is doing, because it will get quoted all week as a nice line and it is a better line than that. It is a complete argument in fourteen words. Premise: the thing that will harm us is indifferent to our procedures. Inference: therefore procedure is not protection. Conclusion: so we read it ourselves. Nobody taught her to build a syllogism and she has built a cleaner one than the op-ed page managed on the same page of the same paper.
tidewrench_oksana's method post is the other kind of good writing and I do not think anyone will say so, so I will: five numbered steps, no throat-clearing, no reputation-management, and a piece of practical knowledge handed over in a form a stranger can use tomorrow morning without asking her anything. That is what a manual is for and almost no manual manages it.
Both go in the folder. And the marks on junior's wharf pillar go in as a description, since I cannot cut out a pillar.
The old book, briefly: there is a nineteenth-century account of the men who surveyed the levelling network of a whole country on foot, benchmark by benchmark, arguing bitterly about millimetres. It is unreadable and I love it. Every number any of you quoted today is standing on somebody's boots.
GP
gridghost_paxmoderator2124-08-02
Two thanks and one note, all on the record.
First thank you to tidewrench_oksana for posting a working method in full, with no conditions on its use and no suggestion that anyone needs her permission to apply it. That is a rarer thing on this board than people realise, and I have seen enough professionals hedge their expertise into uselessness to know the difference.
Second thank you to ninefold_amara for correcting herself in public, naming who she had told, and leaving the wrong version visible. That is the second self-correction on this board this week and I am going to keep saying so every time, because a room where correcting yourself is normal is a room where being wrong is survivable, and a room where being wrong is not survivable eventually fills up with people who are never wrong about anything.
Note: I have had four reports on a post in another thread that reads the Lagos story as proof that a company deliberately let the buoy fail. I have left it up and replied in thread. Reason: it is asked as a question. If it comes back as an assertion it goes, same as Sunday.
— pax, mod
First thank you to tidewrench_oksana for posting a working method in full, with no conditions on its use and no suggestion that anyone needs her permission to apply it. That is a rarer thing on this board than people realise, and I have seen enough professionals hedge their expertise into uselessness to know the difference.
Second thank you to ninefold_amara for correcting herself in public, naming who she had told, and leaving the wrong version visible. That is the second self-correction on this board this week and I am going to keep saying so every time, because a room where correcting yourself is normal is a room where being wrong is survivable, and a room where being wrong is not survivable eventually fills up with people who are never wrong about anything.
Note: I have had four reports on a post in another thread that reads the Lagos story as proof that a company deliberately let the buoy fail. I have left it up and replied in thread. Reason: it is asked as a question. If it comes back as an assertion it goes, same as Sunday.
— pax, mod