Webbased GISLecture 1

• Types of web maps and web GIS • OGC Web Map Servers Google Maps • Basic and advanced use Mapserver • Server based map applications • Local and remote data sources • Databases and spati

School of Geography

FACULTY OF EARTH & ENVIRONMENT

GEOG5870: Web-based GIS

Lecture 1

Oliver Duke-Williams

o.w.duke-williams@leeds.ac.uk

Week 1 Introduction

Introduction to module

• Module structure, timetable and assessment

Web-based GIS

• What do we mean by this?

• What types of web-based GIS are there?

Week 1 Practical

• Discussion of this week’s practical task

Module structure

Blended course of face-to-face and on-line materials

Weekly practical classes

Assessment for the course is based on assessed course work

Lecture timetable

Three weekly cycle:

• Week a: Face-to-face lecture

• Week b: On-line lecture

• Week c: On-line lecture

Each week will be accompanied with a practical class

Module outline

Introduction

• What is ‘web-based GIS’?

• Types of web maps and web GIS

• OGC Web Map Servers

Google Maps

• Basic and advanced use

Mapserver

• Server based map applications

• Local and remote data sources

• Databases and spatial data

Assessed work

• Planning and constructing your assessed work

Web-based GIS

What is ‘web-based GIS’?

Types of web-based GIS

Differences between web-based and other GIS Growth in power of web-based GIS

Web Map Servers and Web Feature Servers

What is “web-based GIS”

• Does not require specialized client

• Differing degrees of support for different

graphics formats etc.

• Growing platform variety

A map-based system that is delivered via a web browser

“web-based GIS”

SVG example

www.statistics.gov.uk/populationestimates/svg_pyramid/uk/index.html

GIS and the mobile web

Mobile web platforms have additional advantages and disadvantages

• Small screen size

• Constrained user input

• Readily available location

• Location based services

What is “web-based GIS”?

• Does not require specialized client

• Differing degrees of support for different

graphics formats etc.

• Growing platform variety

A map-based system that is delivered via a web browser

Map data on the web

Web mapping

Web GIS

Web cartography

Types of web GIS

What types of web-based GIS are there? How might we classify them?

• Examples

• Classification attempts

Google Maps

www.casa.ucl.ac.uk/googlemaps/OAC-super-EngScotWales.html

Google Maps

More examples - transport

www.trafficmap.co.uk

www.bbc.co.uk/london/jamcams_interactive_map.shtml

Weather maps

www.usatoday.com/weather

www.snow-forecast.com

Physical phenomena

earthquakes.tafoni.net

Peng (2001) and Campagna and Delano (2004) has studied the use of Public Participation GIS (PPGIS) over the Internet, and have separately suggested some useful classificatory

terms

Peng, 2001

Peng describes a framework for classifying web-based public participation systems (WPPS) Development of internet GIS

• Internet as a way to disseminate digital data

• Linking existing GIS programs to the web to offer simple functionality

• Distributed components offering rich environment

Functions and features: Peng

Internet based and platform neutral

Distributed database management

Map-based coupled with HTML based interface

Analysis models should be supported

Multiple communication channels

Proper system to support voting and expressing preferencesHighly scalable

Compatible with current standards

Campagna and Delano

Adapted Peng’s taxonomy

Produced a Content / Technology matrix to assess public administration sites in Italy

Content types

Increasing technical sophistication

Content / Technology Matrix

Content / Technology T1: Web browsing and

static maps T2: Interactive map images T3: Interactive dynamic maps multimedia, 3D

representation

T4: Interactive map based search; query and analysis – basic web GIS functions

T5: Web-GIS advanced functions – Planning & Support Systems

Content examples

C1: General information

• Tourist maps

• Other location maps

C2: Environment and planning

• Local planning applications

• Submitted map documents

C3: Raw data

• Raw data for users to download

C4: Analysis tools

Technology examples

T1: Static maps

• Embedded images in HTML or PDF documents

T2: Interactive maps

• May be integrated into the site or via a link to a 3 rd party such as Multimap

T3: Interactive dynamic maps

• Features may include multimedia and 3D representation

T4: Interactive map based search

• Query and analysis – basic web GIS functions

T5: Web-GIS advanced functions

• Planning & Support Systems

CTM surfaces for Italy

From: Campagna & Delano (2004)

CTM surfaces for Denmark

From: Arleth (2005)

CTM surface for Ireland

From: de Róiste (2006)

Web-based GIS

What is ‘web-based GIS’?

Types of web-based GIS

Differences between web-based and other GIS Growth in power of web-based GIS

Web Map Servers and Web Feature Servers

What are the differences between ‘web-based’ and desktop GIS?

• Universality of interface

• Very limited interface components on the web

• Limited access to locally stored data

• Limitless remote data

• Processing in browser is limited

• Potential of significant server-side processing power

Growth in power of web-based GIS

Recent years have seen the introduction of powerful and easy

to use map based tools

• Introduction of GoogleMaps is the key event in this change

• These have further blurred the distinction between web-mapping and web-GIS

• Dangers in the ubiquity of GoogleMaps

Onwards from Google

GoogleMaps and similar services allow users to generate map outputs using:

• Map base data from Google

• Projections defined by Google

• Potential to use additional data in conjunction

More sophisticated services can draw from a wider range of source data

• Different map bases

• Different projections

• In order to make sense of multiple sources, standards are required

OGC Standards

Open Geospatial Consortium control various important specifications

• Services

• Web Map Service (WMS)

• Web Feature Service (WFS)

• Web Coverage Service (WCS)

• Data formats and standards

• Simple Features for SQL (SFS)

• Geographic Markup Language (GML)

www.opengeospatial.org

OGC Services

• Use web protocols to send and receive information

• Return data plus metadata

• WFS – returns linear data about features

• WCS – returns raster data

• WMS – returns formatted graphical rendering of a map

• Use web protocols to communicate between server and client

Alternate data sources

•Data projected for region of interest

•Privately collected data

•Ad hoc data

www.openstreetmap.org

www.openstreetmap.org

Week 1 Practical task

• Identify four websites that make significant use of map-based interfaces

• These can be UK-centric or anywhere

• Try to find sites with a range of capabilities (i.e from simple to more advanced) and covering a range of primary themes (for example, phenomena of interest to both human and physical geographers)

• Would you classify them as ‘web maps’ or ‘web GIS’?

• What GIS capabilities if any do they sites exhibit?

• Features and usability

• Using your knowledge of GIS, how do you think that any of these sites could

Practical report

• Write a brief report (500-1000 words) discussing the different websites that you have considered covering the sort of questions raised in the previous slide

• Submit paper copy as normal but please also email to me

• Web Cartography: Developments and Prospects

Edited by Menno-Jan Kraak and Alan Brown, Taylor & Francis

• Campagna, M and Delano, D (2004) Evaluating geographic

information provision within public administration websites, Environment

and Planning B, 31 (1): 21-37

• Peng Z-R, 2001, "Internet GIS for public participation" Environment and

Planning B: Planning and Design 28(6) 889 – 905