SzekesfehervarHungary

Kydyr Nazarkulov

Kyrgyz GIS Centre, ACA* GIScience Geodesy and GeoInformatics Department, KSUCTA

Module Spatial Analysis Overview

Content

What is spatial analysis Examples of spatial analysis Types of SA Conclusion

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Definition

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"A set of techniques whose results dependon the locations of the objects being analyzed" Move the object location and result will change … = location dependent

"A set of techniques requiring access both to the locations of objects and also to their attributes"

- Both location information and attribute information are used in spatial analysis

Source: M. Goodchild, 2001

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Extracting new information

Spatial analysis models, revealing trends and phenomena which

otherwise may be lost Controls human intuitions when human eyes

could be misleading

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Input data

InformationSpatial analysis

technique/ methods

Question

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Example of Spatial Analysis applications

von Thunen (1783, - 1850) – isolated city-country

City1

2341 – Vegetables, fruits

and milk products

2 – firewood

3 – crop framing

4 - livestock

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Modified conditions

Source: Wikipedia

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(Dr. John Snow (1813 - 1858)

Example of Spatial Analysis applications

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SA methods/ techniques

Simple … “what is …?” (identification) “where is …?” (search)

… more complex How is object А located to object В? What will happen if… What will be the result of intersection A and B? The best route from A to B? Which objects are located in X1, X2, ..., Xn? …

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Simple questions:

Thematic search/Тематический поиск Spatial search/Пространственный поиск

What is …? = question starts with location information

Where is… ? = question starts with attribute information

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Spatial Query

Query - task for search in a database that meet certain conditions, which is formulated in the query language.

In the process the query information can be sorted and processed statistically, that obtained the mean, standard deviation, sum, and other data values.

Spatial query - is formed under the terms of containing the coordinates.

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Distance Analysis

Euclidean distance- measuring straight line distance between objects or positions

Buffer (classified distance) – discrete zone(s) with fixed distance from the object

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Overlay - Operation of the graphic overlay one layer to

another, resulting in the formation, or a graphic composition layer is derived.The result is presented in a new layer

Use Boolean / logical operators, and cartographic algebra (map algebra).The layers were combined in a operators such as AND, OR, negation, ...Often inherent in the software commands, such as intersection, union, andWeight categories are used when the importance of the different layers.

Mask: absence / presence of characteristics

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Logical operators

Set B

Set A

A And B

A Or B

A XOr B

AND OR XOR NOT

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Overlay operations are:

determine the origin point of the polygon; determine the origin line of a polygon; determine the origin polygon polygon; overlay of two polygonal layers; destruction of similar classes of polygonal boundaries of the layer with generation of a new layer; determining lines of intersection of the objects; join (combine) the objects of the same type; determine the point of tangency of a linear object, etc.

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Overlay operation “Point in Polygon”

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Overlay: Union

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Overlay: Intersect

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Overlay: Cut

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(Re)Classification Goal

group attribute data into ranges of values for simplification

or: change classification scheme Manual (re)classification

Number of classes and class limits can be specified manually

Statistical methods for determining class limits (depend on measurement scales)

Equal interval Natural breaks Quantile Standard deviation Equal area

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Reclassification

reclassification is analytical operation, which is generating map layer with definite conditions.

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Reclassification

Size of objects.

Individual objects

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Reclassification: AggregationAggregation to reorganise data: Qualitative data as well as quantitative

data ranges can be grouped into discrete classes -> Reclassification

Slopes in Degrees

Classified slopes in Degrees

Shallow (0° - 5°)

Medium (>5° - 15°)

Steep (>15° - 30°)

Very steep (>30°)

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Network analysis

Group spatial analytical operations aimed at the study of topological and geometrical properties of the linear spatial objects that form a network, the corresponding graphs.examples:

the shortest path Selection of the optimal route Allocation of resources?

(Possible zone) The nearest services.

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Cost surface analysis How effective (non-Euclidean) distance can be calculated on a

raster? Using the method of "cumulative distance“ Cells assigned a value of costs / difference "Distance" is regarded as the difference between the values of

neighboring cells.

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Terrain analysisTerrain analysis creates new information such as: - Slope - Aspect (Direction) - Visibility - River Catchment

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Interpolation Interpolation predicts unknown values based on

known values located in other locations Tobler’s Law: Location of nearby points are more

similar values than locations situated far away from each other.

Literature Longley, P.A., Goodchild M.F., Maguire D.J. and Rhind D.W., 2002.

Geographic Infromation Systems and Science.john Wliey&Sons, Ltd.

Пространственный Анализ С Использованием Дополнительных Модулей К Настольным Продуктам ArcGIS. ESRI, 2001

http://www.sli.unimelb.edu.au/gisweb/RSAModule/RSA_A_Zo.htm Представление и обработка пространственных данных в ГИС:

Методические указания для студентов специальности 071903 – «Геоинформационные системы» / Сост. И.В.Варфоломеев, А.С.Савельев. Красноярск: КГТУ, 2001, 31с.

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