INTRODUCTION TO SPATIAL ANALYSIS

Four fundamental functions of GIS fall under the manipulation and analysis component (Martin, 1991): Reclassification operations Overlay operations Distance and connectivity measurements Neighbourhood characterisation Will be discussed in the next chapter.

1. Reclassification operations transform the attribute information associated with a single map coverage. E.g. allow the “cause-and-effect” of certain spatial factors be evaluated. E.g. * population densities classified into classes such as 'sparsely populated' or 'overcrowded' etc.) * soil types and farmland values * generalising land use pattern

Example: the darker the more dense the state population MAP

Re-classification Analysis - Association Between Land Value and Soil Types

ORIGINAL CLASSIFICATION GENERALIZED CLASSIFICATION classification provides new patterns/relationships URBAN RESIDENTIAL INDUSTRIAL RURAL FOREST AGRICULTURE ORIGINAL CLASSIFICATION GENERALIZED CLASSIFICATION

Classification (cont.) Land parcels for housing are classed into single storey terrace, double storey terrace and bungalow. Generalisation: single storey terrace, double storey terrace and bungalow are generalised under housing lots

2. Overlay operations involve the combination of two or more maps according to boolean conditions and may result in the delineation of new boundaries of housing market

An overlay of three layers of data b r M e a n o f s i d u l - 5 m . h p 7 4 ( g t v ) 3 8 D G w C y c U K B O R E S 1 2 k W Ordnance Survey Crown Copyright. All rights reserved

3. Distance and connectivity measurements include both simple measures of inter-point distance and more complex operations such as the construction of zones of increasing transport cost away from specified locations. Distance measurement can be used to calculate straight line and network distance. Includes perimeter and area measurements…

MEASUREMENT B D A C DISTANCE PARAMETER AREA/SIZE 5 KM X Y A- B = 20 = 40% B- C = 20 = 40% C - D= 10 = 20% 2 10 km

DISTANCE (STRAIGHT LINE) MEASUREMENT A- B: Alor Setar - Kuala Lumpur 360 KM B- C: Kuala Lumpur - Kuantan 270 KM TOTAL: 630 KM

AREA MEASUREMENT 29.69 1765.635 42.4 177.006 99.928 1470.998 96.084 51.75 97.883 95.026 96.215 23.6 95.231 173.255

4. Neighbourhood characterisation involves ascribing values to location according to characteristics of the surrounding region. Such operations may involve both summary and mean measures of a variable. This can be used to examine positive and negative spatial autocorrelation house price hedonic models.

Neighbourhood analysis of mean selling prices within certain distance of a house Ordnance Survey Crown Copyright. All rights reserved

Other View of GIS Functions Anselin (1998) proposes that GIS functions can be classified as follows Selection Manipulation Exploration Confirmation

GIS functions Selection: involves boolean queries and spatial sampling. This seems similar to the overlay operations function. Manipulation: may be based on attribute data, map data, or integration of both, simultaneously. This means analysing data in an integrated manner where various data as available in the database can be combined in an analysis. Exploration: for investigation of spatial structure and involves description and visualisation. This is relevant to spatial autocorrelation analysis of hedonic models using geo-statistical method Confirmation: for modelling spatial association and/or autocorrelation. This is also more relevant to spatial autocorrelation analysis using geostatistical method.

DATA RECALL can be invoked on spatial and attribute components involves selective search no new objects created examples: * lots owned by foreigners * lots along the substation buffer

LOTS OWNED BY FOREIGNERS

CLASSIFICATION AND GENERALISATION classification - identify a set of characteristics to group together objects. in a vector system, classification involves addition of objects characteristics. in a raster system, classification involves converting or coding cell values. classification examples: Land parcels for housing are classed into single storey terras, double storey terras and bungalow. classification provides new patterns/relationships generalisation: single storey terrace, double storey terrace and bungalow are generalised under housing lots

Housing Age Legend Before 1900 1901-1930 1931-1950 1951 to 1999 Map showing classification of buildings according to age

ORIGINAL CLASSIFICATION GENERALIZED CLASSIFICATION URBAN RESIDENTIAL INDUSTRIAL RURAL FOREST AGRICULTURE ORIGINAL CLASSIFICATION GENERALIZED CLASSIFICATION

converting attribute values for polygon, line and point raster data ... vector data converting attribute values for polygon, line and point raster data converting attribute values of group cell

measurement functions includes distance, parameter and area example: land parcels larger than 5 hectares example: shortest distance from KLCC to Pudu bas station

MEASUREMENT B D A C DISTANCE PARAMETER AREA/SIZE 5 KM X Y A- B = 20 = 40% B- C = 20 = 40% C - D= 10 = 20% 2 10 km

DISTANCE MEASUREMENT A- B: Alor Setar - Kuala Lumpur 360 KM B- C: Kuala Lumpur - Kuantan 270 KM TOTAL: 630 KM

AREA MEASUREMENT 29.69 1765.635 42.4 177.006 99.928 1470.998 96.084 51.75 97.883 95.026 96.215 23.6 95.231 173.255

area and parameter is obtained from coordinates of the polygon nodes ... MEASUREMENT vector data area and parameter is obtained from coordinates of the polygon nodes distance is derived from coordinates of starting/ending nodes is more accurate than raster data

SEARCHING determine values against target object according to a neighbourhood characteristic three parameters need to be identified targets neighbourhood around the targets applied neighbourhood function for resultant values example: total of households within 1 km of proposed shopping mall target-shopping mall neighborhood-in the radius of 1 km function-total residential units

perform as overlay operations ... SPATIAL SEARCH operated as additional points in polygon, line in polygon and polygon in polygon vector data point, line or polygon analysed with neighbourhood polygon using coordinate nodes involves complex calculation with overlapping and out-of-boundary neighbourhood raster data perform as overlay operations

represents ‘distance’ between map features NEIGHBOURHOOD represents ‘distance’ between map features ‘distance’ unit can be in measurement units or other units like travelling time, noise level, visibility distance etc. requires 4 parameters target location - schools, highways, etc. ‘distance’ units - meter, dB, ppm, etc. function for calculation on distance, perimeter, travel time location to be analysed

used to generate buffer zones ... NEIGHBOURHOOD used to generate buffer zones example: a 2km zone along a proposed transmission line alignment; zones exceeds 50dB around the airport neighbourhood is most often complex and involves data from various layers. For example, more than 50dB from noisy roads AND more than 1km from factories AND 15 minutes walking time AND ...

Buffering a Point eg. All area within one mile of a city R Buffering a Line eg. All areas within 100 meters of a road Buffering an Area eg. All areas within 500 meters of a wetlands area.

Buffering

Involves two or more data layers Produces new layers OVERLAY Involves two or more data layers Produces new layers Two types of overlay operation arithmetic overlay logical overlay Arithmetic overlay involves mathematics operation such as addition, subtraction, multiplication, etc.

MAP ALGEBRA (MULTIPLICATION) OVERLAY BY MULTIPLICATION DISTRICT CROP AREA OVERLAY 1 2 3 4 1 2 X 1 = 3 4 B B OVERLAY BY MAXIMUM VALUE 3 3 4 4 2 2 4 3 4 1 + 5 5 5 = 5 5 5 2 4 6 4 1 1 4 4 6 RAINFALL : RAINFALL: RAINFALL: 1980 1981 1980 - 1981

vector data - operation based on the selected data only ... OVERLAY vector data are sometimes more efficient than raster data if data are not dense. vector data - operation based on the selected data only raster data - operation on all cells - even null values

GIS Technology: Relationship between Land use and Crop Productivity Soil Type + Crops Production (ton/ha) Overlay Analysis Overlay Result GIS Technology: Relationship between Land use and Crop Productivity

Noise Zone Map Jalan Raja Uda Jalan Hamzah Jalan Datuk Malik Jalan Abdul Aziz Jalan Raja Alang Noise Zone Map

Area Map For Areas Outside Sewerage Services Sewerage pond Jalan Raja Uda Jalan Hamzah Sewerage pond Jalan Datuk Malik Jalan Abdul Aziz Jalan Raja Alang Area Map For Areas Outside Sewerage Services

Industrial Buffer Zone Map Jalan Raja Uda Pan Malaysian Plastic Jalan Hamzah Jalan Datuk Malik Jalan Abdul Aziz Jalan Raja Alang Industrial Buffer Zone Map