1 Application of GIS in hydrology and water resource management 1 Application of GIS in hydrology...

1

1

Application of GIS in hydrology and water resource management

Application of GIS in hydrology andwater resources management

University of Stuttgart – ENWAT

Part 1: July 24 – 26, 2007Part 2: ?

Dietrich SchröderUniversity of Applied Sciences [email protected]

2

1


Objective:• Almost everything that happens, happens

somewhere. • 80% of all decisions in policies are spatial

related.• Geographical Information Systems are today

state-of-the-art tools for supporting any kind of spatial related modelling and decisions.

• This holds in particular in hydrology and water resource management.

3

1


Aims of the course (part 1):• Theoretical background of handling

spatial related data• Basic principles of GIS• Handling of a GIS by example ArcGISin the context of water resource management

=> GIS is still (and will remain) an expert system!! (which is impossible to learn in a 2.5-day seminar)

4

1


Aims of the course (part 2):

• GIS in hydrology– DEM– GIS and surface hydrology– GIS and groundwater models– Case studies

5

1


Part 1: 24 July – 26 July 2007

Tuesday, 24th JulyMorning session: lecturesAfternoon session: exercises in the lab

Wedneday, 25th July: Morning session: lecturesAfternoon session: exercises in the lab

Thursday, 26th July:Afternoon session: exercises in the lab

Examination: test

6

1


Outline Part 1 • Overview of GIS• Data modeling• Spatial referencing: Coordinate

systems, geodetic datum, and map projections

• Georeferencing of images• Design of Thematic maps• Analysis of spatial data

7

1


What is Geographic Information System?

A GIS is a computer-based information system that enables

– capture, – modeling, storage, – retrieval, – sharing, – manipulation, – analysis, and – presentation

of geographically referenced data

8

1


• Don‘t mix it:– The software package (e.g. ArcGIS)– The application (e.g. hydrological analysis

tools)

You can apply the same software product for many different applications (and of course use different software for the same application!)

GIS and GIS Application

9

1


Software: ArcGIS, GeoMedia, ILWIS, Smallworld, GRASS,...

Application: Forestry IS, DSS for urban planning, utility management system, hydrological analysis system,...

10

1

Application of GIS in hydrology and water resource management Development of GIS:

from specialist system to Multi-Purpose GIS

mapping(cartography

)

utility management

(network) environmental GIS

(areal analysis)

...

multi-purpose GIS

remote sensing (raster)

• Integrated

• Multi-discipline approach

11

1


Components of GIS

Data Management

Data Analysis

Data Visualization

• Hardware (computer, periphery like digitizing devices, high-end plotters)

• Software (including generic procedurs for analysis)

• Data

• User (his or her expert knowledge

12

1


Life time of the components

H hard-ware

computer, periphery (digitizer, scanner, plotter)

~ 4 years

S soft-ware

programs, extensions, tools, methods

~ 7 years

D data data, rules, knowledge ~ 25 years

U user

13

1


The GIS Cost Pyramide

Hard-ware

Software

Staff / Users

Data

~ 10 %

~ 15 %

~ 25 %

~ 50 %

14

1


Galery of GIS Applicationshydrologycadastreagricultureenvironment geo-sciencesforestry emergency servicespublic services (utilities) navigation regional/local/rural/urban planningtourism...

15

1


Classical Application: Cadastre

Cadastral data is the geo base data for many large scale applications!

16

1


Cadastral data Germany:• ALK (Automatisierte Liegenschaftskarte)• Whole coverage of Germany• Scale level 1:1000 to 1:10 000• Accuracy some centimeter• Content: land parcel (with land use) and

buildings

17

1


Flood inundation mapping for risk evaluation of building insurances

18

1


ZÜRS (Zonierungssystem für Überschwemmung, Rückstau und Starkregen)Zoning system for inundation, backwater, and strong rain

1 river bed

2 Susceptibility class 3 (10 years)

3 Susceptibility class 2(10 – 50 year)

4 Susceptibility class 1(> 50 year)

19

1


Utilities: Sewerage Network

20

1


Utility Network and Orthophoto

21

1


Geo base data 1: 10 000 to 1:50 000 (ATKIS Authorative Topographic-Cartographic

Information System)

22

1


ATKIS- Object-based structure- Whole coverage of Germany- Scale level 1:10 000 to 1:50 000- Accuracy 3 m (as TK25)- Polygons, lines, and points with

attributes- Land use, river, transportation, etc.

23

1


Hydrography from ATKIS

24

1


Analysis of networks is a common task for GIS:rivers, utilities, transportation, …

25

1


Land use

Soil

Geology

Elevation

Soil depth

…

Result: HRU

Combining different maps

26

1


Actual Trends

• 3D landscape visualization and animation

• 3D city models• Mobile GIS• Spatial enabled database systems• Web Services (SOA)

27

1


3D landscape visualization

e.g. ArcGis 9.3, G-Graphix (Freiburg), Skylinesoft (Israel)

Vierwald-stätter See

28

1


3D City Model Hamburg

29

1


3D City Model Stuttgart

30

1


Mobile GIS

31

1


Tablet (rich client) to smart GPS receiver (thin client)

32

1


In recent years more and more functionality has moved from GIS to database systems like Oracle (locator and spatial)

Spatial enabled database systems

33

1

Application of GIS in hydrology and water resource managementOracle Spatial• linear referencing system• Over 400 Spatial functions such as centroids and

aggregate functions (e.g. unions• and user defined aggregates)• GeoRaster data type that natively manages

georeferenced raster imagery • A data model to store and analyze network (graph)

structure• A data model and schema to persistently store and

update topology• Spatial analytic functions• • 3-dimensional data type support for terrain and city

models and virtual worlds,• support for LIDAR-based map production• Spatial web services support (WFS 1.0, WFS-T 1.0, CSW

2.0, OpenLS 1.1, web

34

1


Web Services (Service oriented Architecture)

From desktop GIS to server GIS

35

1


GIS Classification• Professional GIS (full functionality)• Desktop GIS (reduced functionality, mainly for visualization of spatial data)• CAD GIS (program with GIS functionality based on a CAD)• Internet-GIS (GIS Server) (Client-Server architecture with a Web-Browser and an application server)• Business-Map-GIS (simple cartographic tool with some

GIS functionality)• Mobile-GIS (for mobile use, in particular for data collection and updating)

36

1


Top Ten 2004 per seats (professional GIS)

ArcGIS ESRI 240 000

GeoMedia Professional

Intergraph 196 000

Erdas Imagine Geosystems 140 000

GRASS GRASS Developer team

30 000

Smallworld GE Network Solution 30 000

Geomatica – EASI/Pace

CGI Systems 12 000

37

1


Top Ten 2004 per seats (desktop GIS)

ArcView 3.3 ESRI 1 200 000

GeoMedia Intergraph 515 000

MapInfo Professional

MapInfo 300 000

MicroImages TNTAtlas + TNTlite

GIS Team 20 000

Sicad Spatial Desktop

Sicad Geomatics 10 000

…

38

1


Top Ten 2003 per seats (others)

Autodesk Map Autodesk

170 000 (?)

CAD GIS

Geograf/Ingrada

HHK / Softplan

12 500 CAD GIS

MicroStation Geographics

Bentley Systems

6700 CAD GIS

Mappoint Microsoft ? Business GIS

Regio Graph Macon AG

25 000 Business GIS

…

39

1


Summary• GIS for visualization• GIS for integration• GIS for analysisof spatial data

In both surface water and groundwater modeling, data management plays a major role. The compilation, analysis, and formulation of model input are the major phases of any modeling study, as is the creation of high-quality, graphical model output.Much of the data required for model development, including land use maps, soil types, production well locations, basin delineation, water quality, recharge, evapotranspiration, parcel data, etc. are being made available in the form of GIS coverages. A GIS allows users to take advantage of the vast quantity of data available today for water resource applications.

40

1


Literature• M. Gurnell, D. R. Montgomery (Editors): Hydrological Applications of GIS (collection of papers)• J. Fürst: GIS in Hydrologie und Wasserwirtschaft, Wichmann (in German but with many references)• D.R. Maidment: ArcHydro, ESRI Press• D.R. Maidment: Hydrologic and Hydraulic Modeling Support with GIS (HEC-Ras related)

• M.N. DeMers: Fundamentals of Geographic Information Systems, Wiley&Sons

41

1


Spatial Modeling

42

1


Outline• Modeling the real world• Discrete objects and continuous fields• Vector and raster representation• Managing spatial and attributive data• Object based data models• Process modeling• Dimensions• Topology

43

1


Modeling the real world

real world

Perception of the world:

models of geographic phenomena

database

representation

process model

map

44

1


What is our „model“ of the river Neckar?• A polyline on the a map 1:100 000?• A polygon on a map 1:1000?• A trench in the earth surface?• A habitat for animals and plants?• Is it a waterbody exactly defined by its

channel banks?• Is it a continuous varying field of the

river bed‘s elevation?

45

1


Moving from the real world through various data models to model output requires transformations in both information structure and information content. These transformations from the real world to binary representations include:•abstraction, generalization and selection of relevant concepts, processes and relationships in the real world •conceptual modeling of the relationships between abstract entities •mathematical modeling of the relationships between defined entities •physical sampling of the real world •storage of data in computers - may or may not include the necessity to model space •transformation of data between different representations (models).

46

1


Geographic Phenomena

Something of interest that

• Can be named or described

• Can be georeferenced

• (Can be assigned a time (interval) at which it is/ was present)

What is present? building, river,…

Where is it? coordinates

(When was it present time interval)

47

1


Types of geographic phenomena

• A geographic field is a geographic phenomenon for which, for every point in the study area, a value can be determined.

• Geographic objects populate the study area, and are usually well-distinguishable, discrete, bounded areas. The space between them is potentially empty.

48

1


Continuous Fields: elevation

49

1


Continuous Fields: rainfall

50

1


Continuous Fields: pH-value

51

1


Geographic Objects: Utility network•Sewage canal

•Manhole

•Valve

•Building

52

1


Geographic Objects: river network

53

1


Discrete Fields: Land use classification

54

1


Discrete Fields: rainfall classes

55

1


Conceptual Representations

real world

raster representation

vector representation

model of geographic phenomena

56

1


Raster: For Continuous Fields

X Y Z3532500. 5379500. 688.83532500. 5379550. 688.63532500. 5379600. 688.43532500. 5379650. 689.03532500. 5379700. 690.73532500. 5379750. 692.93532500. 5379800. 693.53532500. 5379850. 693.13532500. 5379900. 693.83532500. 5379950. 696.03532500. 5380000. 697.7

57

1


1 ... n 1 . . .

n

cell(35,67)

columns

rows

• imaginary grid over the study area

• only “inner” coordinates

for each cell

• whole grid has to be georeferenced

• stores information on the interior of areal features

• boundaries only implicit

Raster representation

58

1


• location,• value,• resolution, and • appearance

2424

location: 535020E, 3642640Nvalue: 24resolution: 10m appearance: RGB(255,0,0)

59

1


• In GIS usually squares are used as cell form• Location of each cell as inner coordinates,

specified are the coordinates of the upper left corner of the whole grid and ist direction towards north, e.g. for cell(35,45):x35=xul+35*resolutiony45=yul-45*resolution

• The meaning of the value depends on the application, e.g.– Intensity in a RADAR or LASER image– Classification of an RGB satellite image (range of

values) for land use– Calculated combination of different band of a

satellite image like NDVI (Normalized Difference Vegetation Index) using infra red

– Elevation above sea level– …

60

1


NDVI from NOAA-AVHRR satellite for February and May 1997 showing the photosynthetic activity

61

1


Floating point versus integer grids

1 forest

2 Farmland

3 grassland

Value land cover

•Only integer grids can have a VAT (value attribute table)

•Some operations only work on integer grids

•Integer grids are mainly used for discrete fields like land use

•Floating point grids are used for continuous fields like elevation (DEM)

VAT

grid

62

1


Raster Resolution

63

1


Cell raster: the value is an average value for the whole cell

Point raster: the value is the (interpolated) value of the cell center point

64

1


Advantages of the grid or raster representation

• simple concept• easy management within the computer; many computer languages deal effectively with matrices, e.g. MatLab • map overlay and algebra is simple: cell by cell• native format of satellite imagery and scanned images• modeling and interpolating is simple, because the grid is dense and complete

65

1


Disadvantages of the grid or raster representation

•fixed resolution, can’t be improved. So when combining maps of various resolutions, you must accept the coarsest resolution•information loss at any resolution, increasingly expensive storage and processing requirements to increase resolution•large amount of data especially at high resolution•not appropriate for high-quality cartography (line drawing)•slow transformations of projections (must transform each cell)•some kinds of map analysis (e.g. networks) is difficult or at least not ‘natural’•no correspondence to real world objects, i.e. difficult to link additional attributive data

66

1


Rasterizing Continuous Fields

67

1


Rasterizing Discrete Objects

68

1


Cell size of the raster determines ist resolution: cell size max. 50% of the smallest object to be recognized

69

1


Vector Data

70

1


point

line

area

Vector representation

Geometric primitives

71

1


Vector data and attributive data• Can be easily linked to additional

information

River segment:

Name, Code, Length, quality, …

Gage station:

Name, Code, temperature, discharge,…

72

1


Advantages of the vector representation

•precision is only limited by quality of the original data•very storage-efficient, since only points about which there is information or which form parts of lines and boundaries are stored•structuring the data logically is very easy•explicit topology makes some kinds of spatial analysis easy•high-quality output

73

1


Disadvantages of the vector representation

•not suitable for continuous surfaces such as scanned or remotely-sensed images and models based on these•time consuming capturing (digitizing, field survey)

74

1


Continuous fields in vector representation

TIN (Triangulated irregular network)

75

1


TIN as a Delaunay Triangulation

Non overlapping triangles, no other point in the outer circle of a triangle

76

1


Contour lines

77

1


Vectorizing rasters

lines polygons

Additional smoothing algorithm necessary!

78

1


Data Types in vector GIS

• Geometry Datae.g. 3433989.35/5399102.09

3433060.42/5398073.89

• Graphical Description (symbology) e.g. width: 3mm

color: bluepattern: dotted

• Graphic Data: Geometry + Graphical Description

X

X

X

X

79

1


• Attributive Data e.g. Type: ephemeral river length: 2 km Name: Thirsty Creek

• Topology Information e.g. upID: 23 downID: 56

• Other Datae.g. Multimedia data

ID Type Length_km

Name

…

34 Ephemeral 2 Thirsty Creek

80

1


The feature representation of geographical objects

OID Geometry topology timestamp attributes (neighboring polygons) landuse owner

12456 x1,y1 122423 1. Jan. 2000 forest Smith ... 435666 xn,yn 655680

A feature

• has an object identity

• has a property set (attributes)

• usually has a geometry, i.e. one of the property is geometric associated with a reference system

• may have various relationships to other features

81

1


geometry

graphical description(per feature class)

attributive data

OID

e.g. ESRI‘s ArcView Shape-Format:

• geometry: Shape-File (*.shp)

• attributive data: DBase-File (*.dbf)

• „link“ or „index“ file (*.shx)

• graphical description: Project-File (*.apr)

How to store and manage this information?Approach 1: separated storing of geometry, graphical description and attributive data

Still one of the most often used format for data exchange

in GIS!

82

1


How to store ands manage this information?Approach 2: storing geometry and the graphical description for each feature separated from the attributive data geometry + graphical description

attributive data

OID

e.g. Autodesk‘s AutoCAD-Map:

• geometry + graphical description: DWG or DXF-File

• atributive data: Database-File

Most GIS support the direct import of CAD data

83

1


How to store ands manage this information?Approach 3: storing geometry and attributive data together, but separated from the graphical description

geometry + attributive data

graphical descriptionfeature

class

e.g. ESRI‘s ArcGIS (Personal Geodatabase, real database systems like Oracle, Informix, DB2)

• geometry + atributive data: Database-File (MS-Access, Oracle)

• graphical description: Map-File (*.mxd)

84

1

Application of GIS in hydrology and water resource managementData Modeling in UML (Unified Modeling Language)

85

1


Features versus objects• Only attributes, no operations• Mapping on „flat“ database

tables structure like Personal Geodatabases– No inheritance– No complex objects, i.e. no

nested tables

86

1


The model and its implementation

87

1


Process Modeling

88

1


Dimensions

2D:

without any height information, only latitude/longitude or Northing/Easting

89

1


2D+1D:

position and contour lines two independent layers

90

1


2.5D:

position with heights as attributive data

91

1


3D surface:

to each position one height is associated

(sometimes also called 2.5 surfaces, don‘t get confused!)

92

1


3D wire frame / volume:

to each position more than one height can be associated

93

1


4th dimension: time

2+1+1D

94

1


time in ArcGIS

95

1


TopologyStructure of objects independent of their geometry. Using continuous transformation, topologic properties remain unchanged

“rubber sheet” transformation

96

1


Characteristics of the space in GIS

• 3D Euclidean space. Geometric primitives: points (zero-dimensional), lines (one-dimensional), areas (two-dimensional) and volumes (three-dimensional)

• the space is a metric space, (distance function)

• the space is a topological space

• interior and boundary are invariant under topological mappings

97

1


Problems not using topology• lines between adjacent polygons must be digitized and stored twice (slivers and gaps)• there is no neighborhood information• islands are impossible except as purely graphical constructions• there is no easy way to check if the boundary is correct and complete (dead-ends, weird polygons)

slivers

gaps

dead ends

weird polygons

98

1


Vector Data Structures & Topology

99

1


Geographical Objects (Simple Features)

object

coordinates

P1 x1,y1,x2,y2,x3,y3,…,x1,y1

P2 x1,y1,x9,y9,x8,y8,…x1,y1

…

Area-Object by area-object exist explicitly!

Topology only exist implicitly!

100

1


Interoperability

101

1


Exterior

Area (with holes)Line / Polyline

Simple Features – Geometry Definition

0, 1 and 2 - dimensional geometry

Single objects

Groups of similar objects

Object (Feature)

Definitions for

Point

BorderInterior

102

1


Simple Features – Geometry Definition

• only straight connection of points (no curved arcs)

Pecularities of simple feature geometries:

• no topology

Examples for not allowed objects (not simple)

103

1


Topological Structure

Area-object by area-object and topology exist explicitly!

arc Fromnode

Tonode

Left Right

1 1 2 0 P12 2 3 0 P1… … … … …7 7 8 P2 P1… … … … …10 1 13 P2 0

node X y

1 X1 Y1

2 X2 y2

3 x3 y3

… … …

area arc

P1 1,2,3,4,5,6,7,8,9

P2 10,11,12,13,14,7,8,9

… …

node-arc-area (NAA) representation

104

1


Topology has historically been viewed as a spatial data structure used primarily to ensure that the associated data forms a consistent and clean topological fabric. With advances in object-oriented GIS development, an alternative view of topology has evolved. The geodatabase supports an approach to modeling geography that integrates the behavior of different feature types and supports different types of key relationships. In this context, topology is a collection of rules and relationships that, coupled with a set of editing tools and techniques, enables the geodatabase to more accurately model geometric relationships found in the world.

Topology in ArcGIS

105

1


…

106

1


…

107

1


Maintaining data consistency & topology

• some GIS maintain consistency geometrically, i.e. by coinciding coordinates

• maintaining explicitly stored topology is very time consuming

108

1


Data exchange• de-facto-standards like Shape-Format or DXF (only geometry) based on simple features• no real standard for topology• no real standard for symbology• Metadata very important• OGC (Open Geospatial Consortium: initaitives on specification for interoperability

– Simple feature specification– WMS and WFS specification– Symbology encoding– Geo Processing

• tools for data transformation like FME (Feature Manipulation Engine) from Safe software

109

1


Summary• data models and their implementation should

represent spatial phenomena completely and support efficient analysis

• grids for continuous fields (and discrete fields)• discrete primitives for objects (and discrete

fields)• vector-GIS organize geographic objects in

feature classes• GIS are more or less still 2D and 3D surfaces• simple feature is the standard for data

exchange• Topology helps maintaining consistent data

sets• with WebServices data exchange problems will

become less important

1 Application of GIS in hydrology and water resource management 1 Application of GIS in hydrology...

Documents

Transcript of 1 Application of GIS in hydrology and water resource management 1 Application of GIS in hydrology...