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Jul 7, 2013

Project HERACLES : Fieldwork Part 2: 3D Laser Scanning , Finishing Gravity, and the Lady Beekeeper

Our lean mean FARO scanner
3D Laser Scanning: what is it and what can you do with that? A 3D scanner basically takes 100,000 or more samples per second of an (at best stationary) object using laser range-finding, providing a point cloud that can render a highly accurate reconstruction (especially with the addition of a camera). Our new scanner from FARO is smaller-faster-better (and lighter - it can be taken as a carry-on, for example, on an airplane). These types of (active) scans are most useful for reconstructions and as an aid to modeling - the uses are varied, ranging from architectural planning to crime scene investigations (heavily alluded to in Primary Fault) to archeological site investigations (featured in Shaky Ground). Here, for example, one of our published scans from Roman ruins in the middle of Cologne.

I reported last time about our cleaning efforts prior to scanning - absolutely essential for getting a good scan. Luckily the east wall in Tiryns and the north wall in Midea (no direct links to either of the sites - but these links are very useful for background information) were cleaned for us by the crews at both sites for which we are tremendously grateful (thanks to Frau Dr. Demakopoulou, former archeological director at Midea and Frau Dr. Papadimitriou, Eforia of the Argolis, also participants in the HERACLES project, for their organizational help).
The brawny man on the right made the Tiryns east wall pretty for scanning.

 The scanning crew Klaus-G. Hinzen and Gregor Schweppe (also the passive seismic crew - geoscientists must be flexible, versatile and photogenic - WORD!) have made a plan of attack that includes the use of opaque white balls on broomsticks (geophysicists are also resourceful!) placed between the fallen rocks on the wall(s). The balls allow near-perfect alignment of the side-by-side scans. 

Balls on broomsticks amid a Bronze Age Cyclopean wall
 The new scanner needs all of 10 minutes to do a complete 360 degree color scan and even less for black and white. There is barely enough time between scans for the crew to enjoy the spectacular view from Midea. 
 
A momentary respite from the heat and wind to cool the scanner

Heat and wind - significant wind - conspire to slow down and even stop the measurements, especially when the scanner begins to overheat (at around 60 degrees Celsius). But the car air-conditioner serves as a quick cooler-downer (creativity!), the only casualty being Gregor's temporarily frozen hands.

Meanwile, the gravity crew, Evi Seferou and I, finished with traipsing around the Midea acropolis, concentrate on taking gravity measurements at the bottom of the hill - gaining profiles from different directions. After finishing the northernmost reach of our N-S profile, we start out on an E-W dirt road that looks promising because it seems less frequented by vehicles. 

Before we'd gone a scant kilometer, we encountered the end of the road and the beekeepers, a Greek giagiĆ” (and the last in the series) and her husband clad in thick white linen/cotton suits and wide-brimmed hats with face-protecting nets. Evi and I - standing just a few meters from the first of the bee boxes - are wearing black T-shirts. The bee man points at us (and the bees who are making passes at us) and tells us bees hate black. While we hurriedly take our last measurement, the man asks us if we are the ones who have come to count the bees. Instantly distracted (not that difficult, to be honest), I ask (through my translator Evi, of course), so how do you count bees? Turns out that you don't count the bees, you count the boxes - and there are approximately 10,000 bees in a box.


The Greek bee lady and a few of her bees
We adjourn just after and follow the beekeepers to their house in the village of Midea to purchase some of the honey. Because it is a Greek grandmother we are commanded to drink Fanta (you are much too thin! Drink! Drink!) and taste the honey (fabulous). 

The bee lady proceeds to show us pictures of her children (and grandchildren) and asks me questions in Greek, first in a very slow cadence and then louder and more insistent - the international solution to speaking to someone in a language they don't comprehend. Evi is trying not to pee her pants in laughter, especially as she's yelling back answers to the questions - repeatedly - while I try to smile nicely and look like I know what the hell is going on (all of the rapid conversation is not being translated to me - for which I'm grateful, I think). "Is she married!? Does she have any children!?" "Yes!" "She has a son!" And the Greek grandfather meanwhile is mumbling epithets ranging from the mismanagement by the government of everything to the end of civilization as we know it. After we pay for the honey and leave, I realize this is one of those moments that will live with me forever. And if I can't find a way to fit that into a story some way somehow, then I'm not much of a writer, am I?

The guards at Midea


The guards at Tiryns
A few days later, and it's already time to leave. We bid farewell to the environs, to the heat, to the culture, and to the helpful guards at both Midea and Tiryns


A free Greek spirit out for a stroll on Midea

A Helen of Troy contest? We never found out.


Fredocino: the only antidote to the searing Greek heat


Jun 24, 2013

Project Heracles: The Field Work, Part I



Field work, Day 1, was mostly spent unpacking the car, setting up and organizing the field office, establishing the survey base, and disassembling the first batch of seismic stations that had been recording since last September. Then it was off to the supermarket for basic supplies such as 2 liter bottles of water, sandwich making material, tomatoes, cucumbers, retsina, and ouzo. The absolute basics.

Days 2 and 3 were mostly spent in that nasty form of field limbo that geophysicists are sent to when things don't work: waiting for permits, endless discussions about why things don't work, and making trips to get parts and odds and ends. But despite the threat of rain, we made our first passive seismic measurements in Midea. Hurrah!
 
Klaus, Gregor, Hector and Evi leveling seismometers in Midea
  
Evi measuring a GPS location on a rock in Tiryns (they're digging in the wrong place, Indie!)
 Another important accomplishment was checking the extent of our new differential GPS in preparation for measuring a gravity profile extending all the way from Tiryns to Midea. Measuring gravity requires precise locations, especially elevation, because gravitational anomalies – those are the interesting things – can only be well modeled if the single points that are measured with a gravimeter are well known. The tidal corrections, elevation corrections, geoid corrections, etc. and so on, all depend on the accuracy of the locations. We are using a Scintrex CG-5 gravimeter that our Belgian colleagues Michel von Camp and Thierry Camelbeeck at the Royal Observatory in Brussels haven generously lent us for the experiments.

While doing our base station tests, we stopped near the house where we had installed a seismometer last year. The nice Greek grandmother who owns the house saw us and made us come inside where she plied us with cucumbers (from her garden), melons (from the neighbor's garden) and fresh well water. I wouldn't have understood a word of her non-stop exuberant conversation if it hadn't been for our versatile and multi-talented geophysicist helper Evi Seferou. Evi kept up a simultaneous translation of Grandma's speech which alternated between exhortations (Eat! Eat! You are all too thin!) and stories about her children, her garden, and whether we wanted to stay the night and keep her company. We brought her cookies the next day, and she yelled even more loudly over the fence and gave us more cucumbers to take home.
 
A very nice Greek grandmother. Part of me wanted to take her home with us.
 Day 4 was also mostly spent in discussions – it seems that the Greeks are very keen on this. Then after all the tiniest details had been covered, we began to clear the East Gallery in Tiryns in preparation for the 3D laser scanning. It was rank under-gardener work with an industrial weed cutter and hand-pulling dried grasses and the occasional Spritzgurke. Science at its least glamorous. These are the pictures they don't show you in the BBC or Nova presentations about how science works.

Under-gardening on a Mycenaean ruin

Friends for life - Gregor and an industrial-strength weedeater.
 Saturday, we worked until late afternoon – first measuring the gravity along the windy road leading up the slope to the acropolis of Midea. We were only seriously interrupted once by a goat-herding Greek grandmother (the second grandmother in a series of four). She wanted us to move the car because the goats wouldn't go past it. Superstitious goats? Not fond of French cars (Citroen)? She screamed at us (and not the goats) but did not offer us either cucumbers or melons. Her daughter came with a stick and length of thick rubber hose to encourage the goats to follow her. The hose made a low frequency noise as she dragged it behind her that enticed the goats. 

Goat and grandmother
 Evi told me that all the small landholders here have goats or sheep, a few olive or orange trees and impressive gardens (for cucumbers and melons). The government pays a small amount per annum to promote the continuance of the local farming economy. It's not enough to live on. Most of the farmers produce enough for their own use but not much more. 

The road goes ever on and on - the windy drive leading to ancient Midea, for example
Just call me the human raisin because that's what I'll be after another week in the Greek countryside with average temperatures around midday of 34o C in the shade. The east European heat wave is holding strong (probably at least until September), and is now accompanied by a hot wind. This is the perfect weather for a sweaty day in the field. It's the beginning of our second week.
 
 We completed the planned gravity profile between Tiryns and Midea (40 points total) and three passive seismic arrays. It was not easy. Another screaming Greek grandmother – the Greek name for them is giagiĆ” (pronounced yaya – with emphasis on the second syllable) – threatened the passive seismic crew (Klaus-G. Hinzen and Gregor Schweppe) until Evi calmed her down and convinced her we were not out to steal her land or the hidden gold. Greek men on mopeds were asking what we – Evi and I, the gravity crew – were doing on their land. Our story was convincing enough: that we are investigating the substructure, searching for local faults. One cute Greek guy asked if we were looking for gold. Apparently everyone believes there are hordes of gold secreted all over Greece. Nearly everyone has a map from someone's grandfather with an 'x marks the spot'. Myself, I would just be happy with a hidden grotto with cool spring water and some shade trees.
Hot but not bothered

Next up, Laser scanning, wildlife, and more! Greek grandmothers.

Jun 18, 2013

Women on Wednesday Interview

Reproduced below is my interview with the Pubslush blog Women on Wednesday feature. Pubslush is an interesting and potentially useful crowdfunding concept that also contributes to increasing literacy (focused on children) with giving partners (for example, Flying Kites in Kenya). They are a hybrid corporation (that is, they have both profit and non-profit status.) I am not affiliated with Pubslush and have no experience with their publishing arms and therefore cannot say anything about them, either good or bad, but they included an interview with me on their website and I'm grateful for that. My advice is, if you are interested in such a venture and want to be a part of their team, look at the terms carefully, and then ask them for more details before entering into any binding agreement - which you do even if you submit to them.

Here's the link to the interview, and again, my appreciation to Genevieve Little of Pubslush for including me.