GISBasic Principles

What is GIS?

Geographical Information Systems…GI Science (NB rebrand taking hold: Spatial Data Science)

Conceptualising reality in a computer model

Not just maps or manipulation

Why is GI important? Everything happens somewhere Ability to attach multitude of information Relationship between phenomena

spatial co-incidence relate/transfer info (attributes) between layers where co-incide

Functionality

Data acquisition/integration

Data management/database management ‘electronic filing cabinet’

Data analysis Decision making

Visualisation/cartography

Data Types I: Vector

Discrete entities with specific location Multiple attributes for each feature

Point Polyline Polygon

Longley et al., 2005: 77.

Data Types II: Raster

Continuous surface with changing values Elevation and derivatives Satellite imagery Photographs Scanned maps

Attributes Each cell has single value This can relate to Value Attributes

Examples: Vector

Mapping schools, hospitals, retail outlets, etc.

Points

Multiple attributes can be recorded Type of facility Number of users, staff, etc. Turnover, vol. of sales, success rates, infection rate, etc. Date built, condition of buildings Record number

And of course implicitly – spatial reference/location Permits spatial analysis, incl. of all the attributes above Point-pattern analysis

Examples: Raster

Display density of alcohol outlets in Scotland

Grid (of usually square cells)

Each grid cell can show value relating to density of outlets per unit square

Aggregate (zonal) measures of one variable per grid

GIS – Data Capture

In the field – data capture and recording; primary data Vector Fieldwalking

Point locations Incidents Street Furniture

Line Surveys Transects Elevation Profiles

Polygons Land Parcel Capture Exclusion Zones Conservation Areas

Contour surveys Full Plans

In the lab – (automated) digitising, geo’l text analysis

www.english-heritage.org.uk

GIS – Data Sources Maps

Modern Can be vector or raster OS (OpenData, MasterMap) Enviro, e.g. CEH, BGS

Historical Old OS BGS? Other Historic Maps/Plans

Topography

Geophysical imagery

Remote sensing Optical/RADAR/LiDAR

Caracol LiDAR (www.britannica.com)

Databasing

Asset, Data, Facilities, Resource management Land and Property Gazetteers (National/Local) Large Environmental/Scientific Datasets

e.g. Climate, Flood risk, Land Capability, Forestry

More flexible storage and querying Topology preserved Sophisticated querying/spatial testing Handling of large data volumes (Big Data?) Attaching detailed attribute data to spatial objects Analysis of sites/processes within broader context

Databases – Public Access

Public dissemination Search databases online

Examples Data.gov.uk – goldmine! Met Office Rainfall, DTI/BERR Windspeeds, BGS Geology Data ONS OS – GPS network, OpenData, OpenSpace API

Or restricted to Academia e.g. UK (Census) Data Service EDINA Digimap (OS, CEH), MIMAS Landmap CEH/NERC datasets

Lack of standardisation. Not all may qualify as DBMS.

Data Extraction – APIs/ Screenscraping

Many services publicly accessible but limited In number of points that can be retrieved/processed In number of tasks which can be achieved, thus…

APIs/Screenscraping: Automation of data retrieval across web Using a mashup (our custom web page code) we can 'run' a target

web service with different inputs and extract desired information from the returned web page

E.g. Twitter, Foursquare, Facebook…. "Big Data" See: TwitterMap, TweetMap, etc. But also gov, enviro, health – see OpenCensus proj in R

Smart Cities/City Science/Sensor Networks VGI/Crowd-Sourcing

The one million tweet map

Trendsmap – mapping the #hashtags

Visualising Movement/Flow

Interesting Maps on the Web

These just appeared as I was preparing today’s materials:

http://matadornetwork.com/life/57-worlds-interesting-maps/

And, we can have interactivity

http://earth.nullschool.net/

Or, even a 'full' GIS in a browser…

Distributed GIS – GIS online

BGS Geology of Britain viewer

GIS in your Browser

Google Maps (and Google Earth) Basic Functionality Online Full Power via JavaScript powered web pages Over-reliance on commercial megabusiness?

OpenLayers Free and Open alternative (NB Open <> Free)

Other web map tools: E.g. MapServer, GeoServer

Full GIS Software – ESRI’s ArcMap

Market leader in GIS software One of several ESRI ArcGIS packages – ArcScene, ArcCatalog… Can handle most data types At a basic level, is helpful for cartography and visualisation Many forms of analysis available

Multi-criteria analysis (prediction modelling) Visibility Cost surfaces Networks…

However – Closed, proprietary software; (tho ArcGIS Online to compete with Google) Not the only program available, and expensive (tho some other free

components) Alternatives: MapInfo, GeoMedia, FME, CadCorp

Open Source GIS Much open source software available; modifiable, extensible, fixable! GRASS, Quantum GIS, gvSIG – many make use of GDAL/OGR libraries http://opensourcegis.org/

Or e.g. R or Python – stats, programming – both oft used for maps

http://www.shc.ed.ac.uk/projects/longwalls/Methodology/Visualisation.htm

Büyük Bedesten

Casal de Freiria

Rua and Altivo, 2011: 3302

USGS (Sept 2011) – LiDAR particularly good for trees (top and bot = first and last)

(Now) We’ll Have Manhattan…

U.S. Army JPSD/NOAA / www.britannica.com – a decade earlier (2001)

3D (2.5D) fly-through animations

Previous examples may require GIS data/model be fed to 3D modelling software for detailed work (or that model be constructed in dedicated CAD/3D software)

We can however very quickly create effective visualisations of 2.5D landscapes in e.g. ArcScene (and we can import 3D models from CAD/3D software)

We can also very quickly render animated visualisations of landscapes in GIS software

One example! (NB may not be made with Arc!): http://

www.satimagingcorp.com/gallery/quicktime-north-korea.html

Think!

We must be cautious when using computers Demonstrate how models are developed, and

provide information indicating our depth/lack of knowledge

Full publication (data, methods, limitations) ‘Knowledge representation’-what we think we

know

Don’t be blinded by their ‘scientific aura’ Don’t use them for the sake of it: question them Technological determinism Don’t tacitly accept their results…

Questions to ask before starting GIS analysis

What am I trying to get the GIS to do? How does this relate to my aim?

What data are available and will more need to be created?

What about data quality? Completeness? What is the state of scientific/area

knowledge? Therefore, how appropriate are the data? What is the most appropriate scale at which

to work? And what scale/resolution are the data?

Limitations of GIS Data quality

Different bodies hold data; different standards Currency, Completeness

Representation of reality; and not 3D but 2.5D Technological determinism

Packages can only perform certain operations Algorithms themselves can be restricting

Experiential/Subjective difficult to analyse… GIS/RS works fast over large areas, but final decisions

made at local scale/scale of day-day human experience

Big Data Volumes may allow behavioural analysis, modelling of supply and demand, etc. but temporal GIS still limited (as is true 3D, 4D, 5D, etc…)

Questions?

If not, then…

Practicals!