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Point Cloud Modeling the Alpine Landscape | Christophe Girot | TEDxZurich


I just wanted to explain before we go

into this venture what this point while

modeling is about we founded seven years

ago the ETH together with professor

Greer Egham a laboratory bridging

engineering and architecture it was

supported by the Swiss National Science

Foundation and the school board the ETH

School Board and what happened is that

we transferred a technology that was

privy to engineers and surveyors and

brought it into the realm of modeling

and the way we argued with the Swiss

National Science Foundation is we

basically said well there’s no such

thing as a landscape modeling laboratory

a DTH but not even in Europe or probably

worldwide we’d like to bring this sort

of large-scale modeling from the virtual

world into a reality and make it

accessible to younger generations of

researchers and students so that’s

actually what we did what you’re going

to see is going to require a little bit

of a gymnastic to understand how this

sort of visualizing occurs but actually

what you’re looking at in this picture

is a still picture of a model it’s a

gigantic digital model showing the

entire Alpine chain ranging north south

over the Guittard

before we start I think that we should

define first what a point cloud is made

of it’s actually made of millions if not

billions of pixel points the pixel

itself is a recent word in the history

of mankind it appeared in 1967 at NASA

actually in the Jet Propulsion lab

Billingsly when they satellites and and

spatial missions were sending back

electronic image to earth and it simply

means picture element it’s the smallest

unit visible unit on a digital image or

screen it goes back actually to 19

century theories German person called

Paul nip cough first talked about a

built Punk’d the basically that’s what

the entire cloud is made of so what is a

cloud it’s basically a set of points

that carry information each point

carries in a way a position relative to

its neighbors and the black space in

between is simply no information and as

I said until recently these data sets

these point clouds were used by very

serious engineers civil engineers mostly

to draw precise technical plans and

elevations on construction sites like

dams and other things and the image

itself while the model itself was never

made fully the information was extracted

and 99% of the point cloud information

was thrown away what happened with this

laboratory is we bridged the two fields

engineering and creative architecture

and kept the entire datasets as they

were and started working with these

unwieldy models that count billions of

points basically each point carries the

famous GPS coordinates the X Y Z that

assesses slant latitude longitude and

elevation and you have within this

family of point clouds these so-called

control points that anchor the entire

cloud in precision and we’re talking

about millimetre in terms of height or

width the position is within millimeter

precision these control points are

actually riveted to a series of

satellites that go around the earth and

really give that fixed position the

control point also helps to bring

different sets we use drones we use

terrestrial lasers we use lidar mobile

cars that register elements and these

control points allow us to bring things

together so much for the technical

explanation I think the best way to

explain that is to start again with the

point within a point cloud so that you

can’t stand the sort of phenomenon that

I call trance duck

scale what happens is you can go from a

minut scale of an object to the very

broad scale of a territory seeming

seamlessly and that’s quite

extraordinary so let’s start our journey

here we’re going to see a pixel point

retracting into the virtual digital

space of the new net tunnel this is

actually a data set that was given to us

by the ARP transit of the entire new

high speed rail tunnel in Switzerland

the longest in the world and here we’re

retracting out of the south portal which

is in BO do very slowly and we’re going

to pull out at the scale of an object

and as we go up in the air we’re going

to literally start seeing and this is

all a point cloud data set we’re going

to start seeing the model in a much

bigger picture of the environment here

you even see raindrops falling on the

tunnel entrance

they were scanned the forests the

mountains adjacent to that etc so what’s

extraordinary with the point cloud when

you use it as a general data set is it’s

a virtual model it’s a still image but

it has extraordinary precision this is

just the section of the model that we’ve

been scanning at the eth over the last

seven years of the landscape modeling

and visualizing laboratory what you see

this sort of strange little streak on

the upper part of the the plan picture

is actually the datasets that we took

they’re embedded in a Swiss topo dataset

and what you see underneath is the

section through the mountains with that

high-speed tunnel going through if you

look at the screen you also see that her

thin line in the middle of the picture

which is literally the tunnel that you

see in semi-transparency through the

pixel points of the model this is the

tunnel you all know it it’s been very

highly publicized since its inauguration

last June it is quite unreal one really

doesn’t know where the one is under the

ocean or under the mountain the

relationship to the landscape has been

in a way lost here and of course when

you look at what has happened with this

highly technical sort of device

is that you can cross the Alps in

roughly 20 minutes it used to take two

weeks when Goethe went over the Alps and

basically what you see in gray is the

entire mountain landscape having

disappeared what’s good though is that

the Swiss train company the SBB has

provided for us a virtual compensation

they have within the trains as you cross

the tunnel monitors that talk about your

new horizon it’s labeled underneath each

screen and probably it’s the absence

thereof that means that the new horizon

appears on a virtual screen so what

should we say about that I think we’re

going to go back to the point cloud to

try and understand how it actually works

as a model and as a piece and I think

the best way to designate that is to

explain that the model is like a crust

here we’re just south of the Gothic

going down we’re monitoring the earth

crust it’s really showing in the most

intricate details the old tremolo wrote

in the new tremolo Road it’s almost like

a big cake a digital cake which is empty

underneath it’s just really showing the

surface in the most intricate detail

what you’re going to start seeing now

though is the tunnel below that line

that appears in transparency which is

actually the autobahn tunnel the first

tunnel that we’re going to see and it’s

appearing in transparency through the

cross the second line above that looks

like a cloth hanging line is actually

the nail tunnel which is further east

and as we cut through that model as if

you’re cutting through a piece of cake

we see with exact geographic position

the depth of field with the two tunnels

below the earth crust that’s quite a big

will during image and that’s where these

point cloud data sets are actually

producing a sort of revolution of sorts

again the point cloud is a surface that

is geo-referenced and that really shows

an extraordinary amount of texture here

you see the texture in front of the

terrain but you also see the

transparency of the entire mountain

chain behind it goes all the way to the

Mater hole on the far left this is part

of the model again and here we see the

journey

north-to-south so I’ll just let you

travel we’re going to go through the

portal that we just saw before what’s

extraordinary with this vision is that

we actually come down and within the

recognizable human scale we see things

in very very precise positioning I think

here we’re going to get to the portal

that we just left a few minutes before

and what you’re going to see very

quickly is the portal and then the

double pipe of the train line veering to

the right under the mounting crust and

then shooting into the mountain itself

transparently here we’re going up the

hill towards the Guittard

and then we’ll come down over the

devil’s bridge below you see the

motorway tunnel in transparency that’s

really what’s absolutely fascinating

so it’s actually a massive scale digital

model that can be used here we’re

arriving on the Gothard again and then

we go down again with the mote ultra ban

bridge underneath and magician and fluke

The Devil’s Bridge the well-known

Devil’s Bridge on the bottom of the

picture etc going through we’ve been

deploying techniques like drones before

they were celebrated that was 10 years

ago now they’re sort of ubiquitous we’ve

been using the lidar system we even

reserved the Ultra Bank tunnel for

ourselves close it off and measured it

we even have been going to very cold

places this is Matthias scanning the

Guittard what I think is really

important to understand is how this

really works and what its applications

are for the future it’s not just a

nice-to-have model of the Swiss Alps

here we can literally work as engineers

sexually we’re going to cut through the

infrastructure that pours out of the

Alps in Goshen and here you see a very

very precise section showing how the

motorway the railway bridge etc works

and the applications there have been

multiple we’ve worked in Southeast Asia

and Jakarta monitoring flood problems in

slums we’ve been rebuilding artificial

islands in Venice with the same

technology we’ve been working in Israel

and Jordan on the naira your insight to

document archaeological elements and

basically what we’re able to do with

this type of modeling is not just map

the Alps but actually simulate flow

simulate new projects and use it almost

as a tool of participation we’ve trained

hundreds of young researchers and

students for it and I think that’s

really the goal of this laboratory so

basically the entire team behind the

guitar project which was shown

by the way in the Venice Biennale two

years ago and will be shown again at the

ETH Center at the beginning of next year

in June is actually the result of a huge

amount of collaborations I thank you for

your attention

[Applause] [Music]

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