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GIS IN GEOLOGY Miloš Marjanović Lesson 2 7.10.2010.

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Presentation on theme: "GIS IN GEOLOGY Miloš Marjanović Lesson 2 7.10.2010."— Presentation transcript:

1 GIS IN GEOLOGY Miloš Marjanović Lesson

2 Principles of modeling in Geology Introduction – Model definition and modeling scope – Geological model – GIS definition, relations and rolls – GIS-Geology integration Material formats and resources in Geology Geological modeling procedure using GIS

3  Model definition and modeling scope: No uniform deffinition, but Model is a simplified representation of reality – system (Küne, Stachowiack, Stainmüller)  They are crucial for scientific development in any discipline (Physics, Chemistry, Biology, Geology, Meteorology, Urban planning, Psychology…) due to interoperability, comparativeness, generalization, communication and other model features  Classifications of the model by Temporal state: static, dynamic Dimension and resolution: 0-nD; macro-micro Indeterminism: deterministic, probabilistic, stochastic Data type: raster, vector Modeling techniques: white, gray, black-box models  A system is modeled consecutively through model building, model application and model assessment Principles of modeling in Geology What is a model?

4  Geological model  What is Geological model? Difficult to define (observational empiricism, perceptional limitations, uncertainty) Intuitively developed through practice (depends on education, training and experience) A way of transferring or presenting information that captures the essence of the character of the soil/rock mass in a simple form that meets the objectives (Sullivan) So it is a PROCESS not a RESULT!  Modeling principles: From general to particular (regional to local) Balancing the complexity (scale vs. information, accuracy vs. representativeness) Think 5-dimensionally Extrapolate Always regard lithology, soil/rock properties, groundwater and structures Simplification to the essence Principles of modeling in Geology

5  Building a Geological model Formulation of hypothesis Observation/measurement Merging Re-examining and testing of hypothesis  Developing of modeling skills Clustering of data (sorting patterns) Selecting important Perception of details and “getting the whole picture” Learning habits (new discovery says “learn different things simultaneously and in different rooms, with different music”) Reasoning Simplification Using scientific methodology Obtain good mentoring Savants Principles of modeling in Geology

6 Term GIS? A System, analysis or science? GIS in relation to other disciplines Purpose: to visualize, analyze combine, merge together… Fields of application – Geological mapping – Mineral mapping – Hazard/Risk zonation (analysis) – Hydrogeological modeling (Schalstad, Dynlam, Trigg) – Site selection (road route, windmill farm location, building construction site) – RS - spectral signature in relation to geology, vegetation… – Geophysical Contouring and surface modeling General statistics Spread- sheets Desktop and Web publishing Geostatistics Desktop mapping Image Processing (IP) Database Management Systems (DBMS) Computer Aided Drawing (CAD) Artificial Intelligence(AI) Geographic Information System (GIS) GIS is an organized assemblage of computer hardware, software, geographical data and personel designed/trained to efficiently capture, store, update, manipulate analyze and display all forms of geographically referenced information (Voženílek) Principles of modeling in Geology

7  GIS-Geology integration  GIS data structure revolution Storage Generation of new data Editing data Visualization  Integration Isolated Loose Tight Full Principles of modeling in Geology

8  Material formats and resources in Geology  Maps  Borehole logging  Satellite and aerial imagery  Geophysical data  GPS data  Field logs (digital or hard-copy archived) Principles of modeling in Geology

9  Material formats and resources in Geology  Logic, Nominal, Ordinal, Scalar & Directional Data  2-2,5D objects Raster - pixels Vector - vertices, lines, surfaces  3D objects Blocks - voxels Boreholes and interpolating surfaces Thematic surfaces Principles of modeling in Geology

10  Geological modeling procedure using GIS  Knowledge (about object, area or phenomenon of interest)  Conceptual model: Providing a theoretical framework of a case study (example of mineral exploration, landslide analysis) Selecting necessary vs. available conditions Deciding what type of analysis is feasible Expectations Principles of modeling in Geology

11  Embedding GIS 1. Step MODEL BUILDING Building spatial database (the most time-consuming) Selecting the area and scale (motif) Selecting the working projection Data assemblage – input Spatial database for different research levels and end-users Principles of modeling in Geology Scale concept: – Small scale: preliminary investigation (zonation) – Medium scale: (further research, e.g. mapping, directed by the small scale research) – Large scale: (detailed analysis of the selected areas)

12 Input model types – Raster – Vector Spatial data input requirements – Geo-referencing – Digitizing (manual, scanning) and converting – Calculating (interpolation) and processing (raster oriented algebra, e.g. different filters, enhancements…) – Conversion to target data type Principles of modeling in Geology

13 2. Step MODEL APPLICATION – Spatial analysis, processing and modeling of inputs Reclassification Morphometric calculations Buffering Statistics Querying − Type of modeling technique/approach “White box” (physically-based) models “Grey box” (statistical) models “Black box” (AI approach) models Principles of modeling in Geology

14 3. Step MODEL APPLICATION – Integrating the input models in some fashion (heuristic, deterministic, statistic, probabilistic, artificial intelligence) a) Two maps integration b) Multiple maps integration Principles of modeling in Geology

15 4. Step MODEL ASSESSMENT – Statistical comparison of expected vs. obtained results a) Accuracy (%) b) Chi-Square-Tests c) Entropy/Uncertainty d) Kappa-index e) ROC curves (AUC) Principles of modeling in Geology

16 Outline scheme for Mineral exploration example Geological background and rock unit contact map Geochemical data maps of different components (from tables) Geophysical maps (also from table or profile or cross-section data) Temporary outputs of processing/modeling stage (contact distance buffers, density distributions etc) Temporary output maps, conecting some of the sources together (e.g. geological and geochemical) A - Stratigraphic factor B - “Heat factor” C - Alteration factor Final map of mineral potential of sulphidic mineralization (favorability map, ranging from 0-1)

17 GIS IN GEOLOGY Miloš Marjanović Exercise

18 Exercise 1  Explore geological survey web pages of different countries world-wide, and make your selection (choose a country)  Make a short (2 pg. max) report on your assignment. The report should regard:  Description of the Web Map service provided by the chosen survey  Comment of the interface according to your appeal (is it user- friendly, interactive, good or poor graphic design, versatile – provides many different geological thematic layers and metadata)  Maps’ availability for public (cost-free) use and to which extent  Your suggestions for improvement (if any)  One of the exercise term will be reserved for your oral and interactive presentation of this exercise

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