GIS IN GEOLOGY Miloš Marjanović Lesson 2 7.10.2010.

GIS IN GEOLOGY

Miloš MarjanovićLesson 27.10.2010.

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

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 featuresClassifications 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?

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


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


• 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)


GIS-Geology integration GIS data structure revolution

Storage Generation of new data Editing data Visualization

Integration Isolated Loose Tight Full


Material formats and resources in Geology Mapshttp://www.geology.cz/extranet-eng/geodata/mapserver

http://www.geofond.cz

Borehole logginghttps://www.geofond.cz

Satellite and aerial imageryhttp://edcsns17.cr.usgs.gov/EarthExplorer/

Geophysical data GPS data Field logs (digital or hard-copy archived)


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


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


Embedding GIS1. 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


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)

• 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


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


3. Step MODEL APPLICATION– Integrating the input models in some fashion

(heuristic, deterministic, statistic, probabilistic, artificial intelligence)

a) Two maps integrationb) Multiple maps integration


4. Step MODEL ASSESSMENT– Statistical comparison of expected vs. obtained

resultsa) Accuracy (%)b) Chi-Square-Testsc) Entropy/Uncertaintyd) Kappa-indexe) ROC curves (AUC)


• 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)

GIS IN GEOLOGY

Miloš MarjanovićExercise 17.10.2010.

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

GIS IN GEOLOGY Miloš Marjanović Lesson 2 7.10.2010.

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