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Module Spatial Analysis Overview

Module Spatial Analysis Overview. Szekesfehervar Hungary. Kydyr Nazarkulov Kyrgyz GIS Centre, ACA* GIScience Geodesy and GeoInformatics Department, KSUCTA. Content. What is spatial analysis Examples of spatial analysis Types of SA Conclusion. Definition.

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Module Spatial Analysis Overview

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  1. Module Spatial Analysis Overview Szekesfehervar Hungary Kydyr Nazarkulov Kyrgyz GIS Centre, ACA* GIScience Geodesy and GeoInformatics Department, KSUCTA

  2. Content • What is spatial analysis • Examples of spatial analysis • Types of SA • Conclusion

  3. Definition • "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

  4. Spatial analysis technique/ methods Input data Information Extracting new information Question Spatial analysis • models, revealing trends and phenomena which otherwise may be lost • Controls human intuitions when human eyes could be misleading .

  5. Example of Spatial Analysis applications von Thunen (1783, - 1850) – isolated city-country 4 1 – Vegetables, fruits and milk products 2 – firewood 3 – crop framing 4 - livestock 3 2 1 1 City

  6. Modified conditions Source: Wikipedia

  7. Example of Spatial Analysis applications (Dr. John Snow(1813 - 1858)

  8. 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? • …

  9. Simple questions: • Thematic search/Тематический поиск • Spatial search/Пространственный поиск What is …? = question starts with location information Where is… ? = question starts with attribute information

  10. 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.

  11. Distance Analysis • Euclidean distance-measuring straight line distance between objects or positions • Buffer (classified distance) – discrete zone(s) with fixed distance from the object

  12. 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

  13. Logical operators • AND • OR • XOR • NOT A And B Set A A Or B Set B A XOr B

  14. 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.

  15. Overlay operation “Point in Polygon”

  16. Overlay: Union

  17. Overlay: Intersect

  18. Overlay: Cut

  19. (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

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

  21. Reclassification Size of objects. Individual objects

  22. Reclassification: Aggregation Aggregation to reorganise data: Qualitative data as well as quantitative data ranges can be grouped into discrete classes -> Reclassification Classified slopes in Degrees Shallow (0° - 5°) Medium (>5° - 15°) Steep (>15° - 30°) Very steep (>30°) Slopes in Degrees

  23. 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.

  24. 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.

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

  26. 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.

  27. 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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