Sonification - sound of sand - 2

Progress - Last week I did some more research on the Internet and I found new and better keywords. This lead me to better articles and promising software. The techniques I'm looking for are popular in paleontology and they're used for comparing species.
Norman MacLeod of the The Natural History Museum in London has put a series of articles online about quantitative analysis of paleontological data. These describe how shapes can be quantified, compared and classified mathematically. Link here.

The most interesting technique is "Elliptic Fourier Analysis". Using this technique any shape, even the most complex one, can be described by a series of 2-dimensional harmonics. This is demonstrated by this very cool picture:

The Centre Cannot Hold II: Elliptic Fourier Analysis by Norman MacLeod

The mathematics is easy to understand if you've got a technical background. And even better, the author has a list of relevant software packages that can be downloaded from the Internet.

More background literature - The morphometric techniques are explained in other documents as well:

• A very short introduction to circular harmonics.
• The morphometrics website of Stony Brook. It also has a long list of morphometric software packages.
• A personal site with morphometric research (used in archaeology) and some software.

Most promising image software - The most promising software is SHAPE, written by Hiroyoshi Iwata. It is a free software for quantitative evaluation of biological shapes based on elliptic fourier analysis. Link here. If I can get this working it will solve the spectrum analysis part of my project. Then I will only have to find software for the sonification.

Other relevant image software - I've found more interesting software that could be useful for my project but I'll only investigate that further if SHAPE does not work as expected:

• Potrace and autotrace : these software packages translate a bitmap picture into a scalable vector drawing. I don't know how easy it would be to do fourier analysis on their output. (E: Thanks anyway for the tip!)
• PyNGL : a Python language module used to visualize scientific data. A very interesting software package but it has no image processing functionality. But it might be useful for GPS mapping plots.
• SHTOOLS : an archive of software that can be used for spectral analyses on the sphere. This may do the job of spherical harmonic analysis. But it looks too powerful and too complex for my purposes.
• Fiji and ImageJ : image processing software written in Java. Fiji has a GUI with menus.

Less progress with sonification - I haven't found a software package that does simple spectral synthesis just like I need it. But I have found some interesting websites:

• SonEnvir : a research project that investigates sonification in a number of scientific disciplines. It uses SuperCollider.
• MAX/MSP was mentioned as useful software. In the meantime I realize that PureData is a branch of this development and that it has fourier transforms. So maybe I'll have to dive into that too.

Next time maybe real results!

Sonification project - sounds of sand

Sand spectrum - I want to listen to the sound of the shapes of sand grains. This seems a weird idea but it is a standard geological technique. The outline of a sand grain is first extracted by image processing:

And then the roughness of the grain outline is translated into a series of harmonics by Fourier analysis. This is a more formal description of sphericity, roundness or roughness:

Different grains with different provenance have different spectra:

The technique is described in these research papers:

• On the shapes of natural sand grains - David R. Barclay and Michael J. Buckingham - Published 21 February 2009 - JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114 - Link
• Particle Shape Characterisation using Fourier Analysis - Elisabeth T. Bowman, Kenichi Saga & Tom W. Drummond - CUED/D-SoWTR315 (2000) - Link

Software tools discarded - I've spent a lot of time searching for tools. I need tools for image processing and sound synthesis. These don't often go together. I've discarded the following options:

• Matlab - Has image and sound and mathematics. But is prohibitively expensive and probably a steep learning curve.
• Scilab and SIP (Scilab Image Processing Toolbox) - Free and functionality looks sufficient. But I'm worried about stability, reliability and the steep learning curve.
• Processing - Not many examples of image processing, I'm not sure it's powerful enough.
• Supercollider and PureData - I'm afraid of the learning curve.

Software tools chosen - Finally I've settled on tools written in Python. I already know the language, it is portable to both Windows and Linux and it has both image processing and sound synthesis tools. These are the tools I'm going forward with:

• Python Vision - This seems a workable set of image processing tools. I'll just try it for a first start. It consists of a set of image processing tools, described here.
• Python XY - Most of the tool set can be installed in Windows 7 in one go from here. You have to deinstall all other Python software first.
• Two additional modules:
• Pymorph - Downloadable from here. Install by: python setup.py install. No problems here.
• Mahotas - Downloadable from here. This one is more tricky to get working. You get a well known error that is described here. But the solution is different from what is written here. You don't need to install MinGW and you don't need to set the path. I think Python-XY has done that already. You just need to install the module with a different command: python setup.py install build --compiler=mingw32. This worked for me after some googling and experimentation.

I've not yet chosen which tools I'll use for sonification of the images. But there seem to be sufficient tools available. At first sight this looks sufficient:

• Nsound - Seems sufficient. I'm still a bit dubious about the 'buffer' format. Can I write random data into a buffer or am I limited by the functions in the nsound library? The usage of the library looks a bit weird to me.

We'll see if these choices work. I think it would be difficult to find a better match between learning curve and functional power. But I'm open for advice!

Topography - Waddinxveen

It is difficult to write about walks. Ideally the description of a walk should be like good erotica - it should excite and be - in a minimal way - a substitute for the real thing. But when I try it comes out like a biochemical description of the erotic act - technically correct but not very inspiring.

How to write about places like Waddinxveen where - even according to the guide - nothing exciting ever happened and no interesting person was ever born? And what can we learn from such a walk?

We can learn about the fractal nature of human landscapes. About the intermingling of old and new. About the random patchwork of bad and good architecture. And the always interesting differences between the unintentional backsides and showy front sides of architecture. We can see - in a rough way - the year rings of the city, starting in the old center and fanning out to the suburbs.

We can see the remains of 19th century industry when ships with wood arrived here along the canal. And we have to realize that all that furniture industry has been globalized away by IKEA and China. And we see the agriculture in the background, a branch of industry that has remained in the same place for at least 300 years, ignoring changes in technology, politics and EU-subsidies.

And we can witness the flow of car traffic, that modern river that has overtaken the transport function of the canals. Nowadays water transport is only used for heavy bulk cargo like sand, bricks and stone. And for containers from China. But once the oil runs out water transport might become viable again.

We are amazed by the closeness of the urban tendril of the highway and the virgin countryside. Artificial nature maintained in its original state by careful management and tax money. And again a network of smaller transport canals. Trade and money invades every nook and cranny of the landscape.
This mix of economy and landscape is very authentic. Remember the Breughel paintings? How farmers used every inch of the landscape for survival? You're now walking inside this landscape.

The farmers have not moved but they've shifted markets. Where they used to grow fruit for the cities they now grow garden plants and trees. Later these will be transplanted into modern suburbia to give an illusion of nature and private space. In the meanwhile we can enjoy the structured and efficient chaos of horticulture.

Note:

I wrote this piece at the breakfast table in one session without any research. Later looking on the Internet I saw that I had missed the following facts:

• These inconspicuous places can be very old. This place is from the 13th century. The history is totally invisible (I intend to write more about that, how is it possible that centuries have become invisible?)
• It hosts the "Forgotten place". An artwork marking one of the many lowest points in the area, 7 meters below sea level.
• The Wikipedia list of monuments is laughably short. There is a lot more to see when you're "in situ".

I did not consciously copy the style of the previous Gilbert & George entry but somehow it must have entered my subconscious.



Gilbert and George psychogeography

Strange but interesting book - I found this in my old photo files. It is from the Gilbert & George exhibition at Kröller-Müller museum in 2010. Unfortunately I forgot to make a note of the name of this booklet. But another blogger has visited the exhibition and has made a note of the title: Side by Side. The book is very interesting and shows unexpected possibilities for psychogeography.

SIDE by SIDE 

Side by Side we look to you. A fine dark sky is our background. Flowers edge our way along the dusty road and thick leaved trees shade our way. Some shadows on the road. Quite a funny sky in this one with an incredible atmosphere of threatening and dread, late-evening and we must be home before we are too tired, too depressed and happy. Back to sleep, and dinner and Friends and a House.

Strange irony - This text is much more old fashioned than anything Will Self or Iain Sinclair has written. But it is ultra-modern in its self-awareness and alienation. You are never sure if this is meant to be serious or if it's an ironic comment on Victorian landscape descriptions in the style of John Ruskin.

Picture kindly provided by: 5 uur blog

MODERNITY

 Lunatic wonders in the churchyard. Sweet solace is ours for we are old-fashioned enough to see this ancient building. Old-fashioned are our clothes and eyes but our outlook is ultra-modern. And so here we must recognize sadness as the key to our past and future. Where is the balance in which to be two beings with this lovely scene of an old church in such charming trees and front and sides and surrounds.

THE ANCIENT OAK 

Here are Arts two old Men, one bending forward and one bent backwards.Our eyes glazed and shuddering in the reality of the moment. We feel overtaken by the Age around us - this timeless hill and ancient oak. What can we do but sit and stare. Our tired legs shake without rest. Our brows are contorted with imagination and rambling ideas. We are not happy as we used to be for we have seen.

Sources:

Side by Side by Gilbert & George - 1972 - Only 600 were printed. Most are in museum collections. One was sold at Christies for $1300. Not something that you buy very easily.

There is not much material about this book online. I could find one extra page in the "5 uur" blog: 5uur.wordpress.com - many thanks that I could use it.

Strange places - drugs and prostitution

Strange places (for bourgeois visitors) - Sometimes you enter an area innocently, suspecting nothing, and suddenly you are outside your comfort zone and you don't know the rules of the place. Literally, you don't know where to look. For example when you enter the red light district unexpectedly. We had this several times.

Surprise 1 - The red light district of Haarlem is situated on the historic tour of the city. One moment you're reading about the Christian community of the Beguines and suddenly you see half-naked ladies behind red-lit windows. A branch of psychogeography you don't often read about.

"Something strange is going on here," said Pancho, as the taxi driver drove happily away, with a few choice words about our mothers. At first glance the street looked normal, but I too noticed something different about the place I remembered so vividly.

Unknown rules - These areas have their own rules. And as a standard bourgeois person I don't know the rules of prostitution, cruising, drug dealing and crime. I feel disoriented and paranoid in these places. But insiders can find their way with ease.

Score some shit,” said Brown ... Milgrim looked out at the street they were parked on. Five-story brick Edwardian retail structures lacquered with the unhappiness of crack or heroin. The fuckedness quotient way up, down in this part of town. ... “I’ve never been here before,” said Milgrim. “I don’t even know if this is the right street.” - “Are you kidding? Look at it.” - “I know,” Milgrim said, “but a local would know what’s going on this week. Today. Is this where the biz is, or did the police just shift it three blocks south? Like that.” ...
He decided it would be best to behave as though he were shopping for his own flavor of pharmaceuticals. This would up his authenticity immediately, he thought, as he knew what to ask for, and that the units would be pills. This way, if he actually managed to buy something, it might even turn out to be worth keeping.The day suddenly seemed brighter, this foreign but oddly familiar street more interesting. Allowing himself to forget Brown almost entirely, he strolled along with a new energy.

Surprise 2 - The red light district of Alkmaar is also situated on the historic tour of the city. One moment you're reading about the cheese trade and the tulip mania and suddenly you find yourself in a narrow alley with men looking as if they're not there at all. And then you see the windows with half-naked ladies with stockings. Now there is no way back, you have to walk to the other side of the alley. Later you find that you've misread the map.

Surprise 3 - The red light district of Antwerp is situated next to the new modern art museum. It used to be right beside Antwerp harbor, in its natural environment. But now the harbor has moved and the whole area is being renovated and gentrified. This is the last remaining island of original use. One moment you're exploring the remains of the harbor and looking for a sandwich and the next moment you see all these dodgy men. It takes a while before you realize what's happening.

"This is where the whores are," said María. The truth is, at first I didn't see anything to suggest that the street was any different from those we had just been on. The traffic was heavy here too, and the people crowding the sidewalks were no different from the people streaming along Bucareli. But then (maybe because of what María had said) I started to notice some differences. To start with, the lighting. The streetlights on Bucareli are white, but on Avenida Guerrero they had more of an amber tone. The cars: on Bucareli it's unusual to find a car parked on the street; on Guerrero there were plenty. On Bucareli, the bars and coffee shops are open and bright; on Guerrero, although there were lots of bars, they seemed turned in on themselves, secret or discreet, with no big windows looking out. And finally, the music. On Bucareli there wasn't any. All the noise came from people or cars. On Guerrero, the farther in you got, especially on the corners of Violeta and Magnolia, the music took over the street, coming from bars, parked cars, and portable radios, and drifting from the lighted windows of dark buildings. "I like this street," said María. "Someday I'm going to live here."

Sources:
Pictures: Google maps - Street view
Drugs: Spook Country by William Gibson, 2007
Prostitution: The Savage Detectives (Los Detectives Salvajes) Roberto Bolaño, 1998

Urban soil analysis - 2

Artistic soil is the most inauthentic soil

I took this sample from the lawn between Boijmans Museum and the Dutch National Architecture Museum in the center of Rotterdam. Now that I've been looking at soil more regularly I recognize the color and texture well. It can be found on many public lawns and parks in the city. Often it is mixed with garbage and dog shit.

It is a mixture of sand, clay and peat and it is quite characterless. I think it has been mixed, remixed and reworked many times. Uninteresting color and texture, really tired looking, like the sad brown you get when you mix too many colors, something to overlook. I have no idea where it came from. But looking at the dramatic history of this place, it cannot be virgin soil.

Dramatic history - restless soil

The whole area around the museum was reworked during the construction of the museum and the surrounding streets. It's difficult to determine the local geology from this photograph and at first sight it looks like wet heavy clay but the heaps in the foreground might also be wet sand. Notice the Paradijskerk (Paradise Church) and the Nieuwe Binnenweg in the background for orientation.

Then during the war, after the bombardment of Rotterdam and during the German occupation air raid shelters and defensive trenches were constructed in this area. And also during the war vegetables were grown in this area. (This is real survival in the city, not the fashionable modern urban foraging.) Notice the tower of Boijmans Museum in the background for orientation. And the soil in the pictures already looks like a mixture of soil types.

Attempt at analysis

I'm getting better at it. This time I didn't forget to add something for a sense of scale. Soil is a fractal. It is difficult to estimate the scale at which a picture was taken.

 It is easy to see the different components of the soil, the sand grains, the clay dust covering everything and the organic fragments from the peat.

 The organic fragments float in water - roots and other small pieces of old wood.

Very fine clay settles on everything when the sample is mixed with water. Again scientifically irrelevant - but poetically interesting. Soil and water makes beautiful underwater landscapes, like lost civilizations. And maybe this soil contains authentic memories of Rotterdam.

Sources:
Some old pictures are from the Rotterdam City archive. So I assume they are public domain, but I'm quite willing to remove them if this is against the regulations. I really like the Rotterdam archive and I've spent a few pleasant hours there searching for weird books on Rotterdam.
The air shelter trenches + Another picture from a different side
I don't know where I got the pictures of the vegetable harvest and the construction of the museum from. I've had them on my computer for two years.

Urban soil analysis

Under the pavement: the beach?

A famous Situationist International slogan by Guy Debord, also translated as: "Under the paving stones, the beach". But has anyone really tried to test this hypothesis? In reality the urban soil under the pavement is  more complex than that. And fortunately the ever present roadworks enable us to study urban soil in detail.

Urban soil layers

At the moment the quay of the 4e Westwagenhof is being restored. The soil has been dug up to a depth of only 1 meter. This no archaeological level, it cannot be older than a few years. But already interesting soil patterns can be observed.

There are 4 layers here, or more. But I'm sure about these ones:

• the paving stones (200*100 mm) - useful for scale
• dry sand - it probably dried during the roadworks
• wet sand - it also could have a relationship with the ground water level
• dark clay - might be more than one layer

The transition between dry and wet sand.	The transition between the sand and the clay.

Methodical errors
I'm learning the craft on-the-fly, without any theoretical preparation. So I make all the stupid mistakes. For example ... I only took a soil sample from the heap of sand that had been dug out of the hole. And I took only the sand. In hindsight the clay layer would have been much more interesting because it is older.

Where I took the sample. Not good.

Another error I made is not labeling the container with the sample. I almost forgot where it came from and had almost thrown it away as worthless.

Soil analysis attempt
Weight = 47 grams (using my digital kitchen scales)
Volume = 33 cubic centimeters (estimated by measuring the height in the container)
Density = 1.4 grams / cubic cm
The density of dry sand = 1400 - 1600 kg / cubic m - so this fits the range perfectly.

There is no smell. The sand contains a lot of tiny fragments of cement and asphalt. The sand grains are small and the sand feels very smooth to the touch. But still there are a lot of different grain sizes; the sand looks very unsorted. And there are no seashell fragments. Most likely this is not a beach! I could test this by tasting for salt, but I don't think it would be wise.

I thought I had a spare tea-sieve, but right now I can't find it.

There are a few "concretions" clumps of sand in a cement-like matrix. The chalk might come from the mortar in the canal walls. Or maybe the sand has been used before on some building site.

Conclusion
Scientifically the experiment is worthless. But poetically it makes you aware of the urban underground and it's unfathomable history. It also highlights the variety of underground soil mixtures, colors and textures. To be continued.