Avalanches on Atlantis

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1 Avalanches on Atlantis Real or Fake? The "true" story! Florian Thiery M.Sc.* Dipl.Geogr. Rania Taani** * i3mainz - Institute for Spatial Information and Surveying Technology ** Hochschule Mainz University of Applied Sciences,

2 That s me! Master Degree (Master of Science) in Geoinformatics and Surveying Research Associate at i3mainz Institute for Spatial Information and Surveying Technology Computer Scientist at RGZM Archaeological Research Institute 2

3 We are living in a world of»fake news«and»alternative facts«, also in history 3

4 But what is REAL, what is FAKE? 4

5 But is fake information always bad? 5

6 Have a look in books, there are fairy tales and myths ideas in mind with real facts 6

7 In Greek history, the famous philosopher Plato mentioned the mythical island Atlantis 7

8 Atlantis was a real empire, assigned to the sea god Poseidon 8

9 but only in Platon s mind, to show and explain his theories! 9

10 In geodesy we try to model and measure the real world as perfect as we can 10

11 but we all know, that it will never fit perfectly! 11

12 For demonstrating geodetic methods in GIS, we do not need real data, if it does not exist 12

13 we can use modelled, faked information for demonstrating anything we want! 13

14 In case of Atlantis, it is hard to get real spatial information out of Platon s work 14

15 because Atlantis could have looked like this 15

16 and modelled in a faked dataset like this: 16

17 The»AtlantGIS«dataset by Prof. Dr. phil. Kai-Christian Bruhn! 17

18 Imagine, you have real problems like avalanches threatening populated areas 18

19 just simulate and calculate demolition sites on Atlantis using the AtlantGIS dataset! 19

20 This was done in a students project by Rania as part of an interdisciplinary GIS module focusing on applications in Digital Humanites! 20

It was an avalanche! Nothing happened, puh! Both were responsible for the well-being of their countrymen. Thus, they were obligated to deal with "avalanches".

21 Rania s scenario One day, there was a great concern on Atlantis. Atlas and his twin brothers gathered for the annual island party at the king's palace as they heard a sound coming from the surrounding mighty mountains. It was an avalanche! Nothing happened, puh! Both were responsible for the well-being of their countrymen. Thus, they were obligated to deal with "avalanches". In order to make protective arrangements, areas prone to avalanches, had to be recorded. To analyse the recorded data, a GIS was established. As a result the demolition sites of avalanches have been calculated and will now be presented to the audience. 21

22 The investigation area, real and faked AtlantGIS Sokotra 22

23 The data is based on a Digital Terrain Model (DTM) for the visualization and analysis of the height, slope, terrain alignment and the vertical curvature current Landsat data for surface roughness (calculated using vegetation information) Data Set Landsat Archive, Pre-Collection, L8 OLI/TIRS QGIS, SAGA, GRASS, GDAL 23

24 Important characteristics of areas prone to avalanches are slope, surface design, snow depth, temperature, wind and the soil character (rubble &. Covering of vegetation) A multi criteria analysis was done for height slope terrain alignment vertical curvature surface roughness 24

25 The digital terrain model in pseudo colour 25

26 The calculations include reclassifications using QGIS Raster Calculator 26

27 Risk areas based on height avalanches occur at a certain altitude, which is oriented at the 0 C frost limit of the area; the higher, the more risk 27

28 Risk areas based on slope major influence! critical inclination for avalanches between 25 and 45 28

second highest risk, south slope (135-225 ) third

29 Risk areas based on terrain alignment north slope ( ) highest risk, west slope ( ) second highest risk, south slope ( ) third highest risk and east slope ( ) lowest risk 29

30 Risk areas based on vertical curvature convex surfaces have higher risks, concave surfaces are more stable 30

31 Risk areas based on surface roughness calculation of the Normalized Difference Vegetation Index (NDVI), lower values higher risk 31

32 Classification based on multi criteria analysis demolition sites = (height + alignment + curvature) * slope * roughness 32

33 The resulting risk areas 33

34 Rania s conclusion the resulting map indicates higher avalanche risks in the north-western part of Atlantis. avalanches demolition areas are not the actual danger zones. Lead-out areas have to be included, too. the identified danger zones have to be identified and monitored. 34

35 My conclusion AtlantGIS is cool! use and extend it! 35

36 Avalanches on Atlantis Real or Fake? The "true" story!

37 License Information Except where otherwise noted, textural content on this presentation is licensed under a Creative Commons Attribution 4.0 International license. Image references are noted, if not Public Domain or self-produced. 37

38 Image References 1/4 Slide ALDODEL via fiverr.com Slide 3 Slide Slide 5 Slide 6 CC BY-SA 2.0 Arun Katiyar ( Slide

39 Image References 2/4 Slide 9 Slide 11 Slide Slide 13 Slide 14 Slide

40 Image References 3/4 Slide 16 CC BA-SA kacebe ( Slide 17 ( ) Slide Slide 20 Slide 21 Slide 22 and OpenStreetMap 40

41 Image References 4/4 Slide 26 By User:Anitagraser on QGIS Wiki, Antigraser ( [CC BY-SA 3.0 ( via Wikimedia Commons Slide

42 See also al/working_with_raster/raster_calculator.html 42

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