GEOMATICS FOR URBAN AND REGIONAL ANALYSIS 2024/2025 PDF

GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) G. Bitelli Geomatics for Urban and Regional Analysis Designing and applying sequence of operations / models to...

GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) G. Bitelli Geomatics for Urban and Regional Analysis Designing and applying sequence of operations / models to answer questions, extract new information, solve problems SPATIAL ANALYSIS IN GIS - statistics and data reports - special visualization techniques - specific geoprocessing procedures, modeling, automate tasks Spatial Analysis in GIS Geoprocessing Example: Geoprocessing can be used to identify suitable sites for parks. The result is a dataset of potential park sites for further evaluation. Site selection logic is used to find areas that are close to where people live but are not too close to existing parks. This model uses the Weighted Overlay tool, where weights are assigned to each input data based on how much it affects the location of a new park. The sequence of analysis operations can be expressed graphically Examples (I) Geoprocessing Buffer – How many things are within x distance of this location? ○○How many offices are there within x distance of this lab, classroom or parking lot? ○○What are the walk times between a parking lot and each facility?

  Overlay – What things are within the boundaries of a specified area?  
    ○○Which offices are within the space described by this lease?
  
     ○○Which security cameras are in this security zone? Proximity – What are the nearest x things to this location? ○○What are the 10 open work orders nearest to this asset? ○○Where are the three soda machines nearest to this dorm room? What is the most What is the Geocoding – Provide a location that corresponds to a given address. suitable site to locate a fastest way ○○Where is 123 Main Street? new shopping center? along a ○○Where is John Doe’s office? slope? ○○Where is phone number 230-0182? What is the closest fire hydrant Density – Show the density of things typically per square unit, such as meter or hectare. to each building? ○○Where is the highest concentration of students at 2 p.m. on Wednesdays? ○○Where is the highest concentration of work orders in the past 30 days? ○○Display the concentration of hot/cold calls over time. Route – Display the fastest or shortest distance between two points along a transportation network (roads, rail, footpaths). How many people could be ○○What is the most direct route from room x to room y if I am wheelchair bound? DICAM involved in the toxic cloud? Università ○○How long will it take to evacuate building x if stairwell y is blocked? di Bologna ○○How far into building x can I get in two minutes? GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) 1 G. Bitelli  GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) G. Bitelli Examples (II) Spatial selection – Select the objects in layer A that are within the boundaries of a feature(s) in layer B. ○○Select all of the fire extinguishers on north campus and schedule them for inspection. ○○Select all of the people scheduled to be in the buildings adjacent to building x and notify them of an emergency event. ○○Select all of the air handlers within the footprint of this project and schedule them for filter replacement. Drive time – Show me all the things or areas that can be aggregated within a specified drive time of location x. ○○What is the cumulative drive time for all employees to facility x? ○○How many employees of facility x live within 10 minutes drive time of public transportation? ○○What is the total retail spending potential of the population that lives within 15 minutes drive time of this Main spatial operators in a GIS proposed store? Temporal – Show the geographic relationship between things over time. ○○Display energy consumption per square foot (square meter) for each building across my portfolio by month. ○○Display the distribution of trouble calls across campus before and after implementing our community security program. ○○Display the footfall traffic across a specific retail mall every 15 minutes throughout the week. Line of sight – What can I see from location x (3D)? ○○How large/high can a building be constructed on this site without affecting the skyline from location y? ○○If this proposed building is built, at what time of the day will location x be in shadow? ○○What locations can be seen from location x? ○○What proposed security cameras will have visibility of location y? OVERLAY by boolean logical operators between QUERY on a single layer two or more maps Example: select all features that have a certain value in a certain attribute or in several attributes. Boolean expressions used in GIS are AND, OR, NOT, XOR. It can only be a selection within the current map/layer or generate a new file (with its own new topological relationships) Venn diagrams Intersection Union Exclusion Exclusive Union DICAM Università di Bologna OVERLAY in the vector and raster domains Overlay polygon-polygon Overlay for OR = vector datasets Overlay line-polygon Boolean operators in the overlay of vector entities AND = of the same or different type Overlay point-polygon NOT = GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) 2 G. Bitelli  GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) G. Bitelli OVERLAY of two by superim posing differentvectorlayers,a vector datasets fragm entation ofthe areas in the finalm ap can be generated Point in Polygon The overlay of two polygons A and B gives rise to B 9 new polygons, 1 of which formed by both A original polygons, 4 from A and not from B, and 4 from B and not from A Overlay of geometry and attributes between two different datasets: properties and soil type Property (3) Owner X Owner Y OVERLAY (5 classes) Public area X2 X1 Y2 1 2 P1 P2 DICAM DICAM Università Soil type (2) Università di Bologna di Bologna Line in Polygon Overlay in a raster domain (I) The resulting raster map C derives A from the application of an arithmetic or Boolean operator to maps (matrices) A and B. B The operation is performed pixel by pixel. C sum DICAM DICAM Università Università di Bologna di Bologna DISSOLVE (single layer file) Overlay in Areas selected with certain attribute raster to values are “dissolved” into the larger (re)classify areas they are in an area Adjacent areas that share the same attribute value can be combined The input layers can be weighted differently when adding (multiplying Also used to eliminate sliver them by the weight polygons that remain after factor) overlaying two maps that don't perfectly overlap DICAM Università di Bologna GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) 3 G. Bitelli  GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) G. Bitelli DISSOLVE CLIP Merges adjacent polygons if they share the same attribute value. a map is "cut" according to the extension of another map (= covers the same geographical area) or according to a cutting feature In the example, MapClass is used as the dissolve item Inputlayer: Cutting feature: Outputlayer:subw ay subw ay netw ork polygon ofthe urban center netw ork ofthe centralarea DICAM Università di Bologna SPLIT ERASE Generates an output layer by superimposing and eliminating the polygonal elements of an “Erase layer” Splits the input layer into as many output feature classes as from an input layer there are polygons of the split layer Split polygons DICAM DICAM Università Università di Bologna di Bologna Spatial operators that operate on the context: NEAR BUFFER The NEAR function calculates the distance of the points of an input layer with areas of influence (buffer areas) the closest points or lines of another layer. created as a function of the distance from point, linear, areal point polyline polygon The results (nearest entity and distance) are recorded in the attribute table for entities each point of the input layer they can also be used to represent the error associated with the geometry of an object fixed or variable distance according to other attributes, possibility of introducing “friction” effects, costs and barriers in raster o in vector domain DICAM Università di Bologna GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) 4 G. Bitelli  GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) G. Bitelli Options in Buffer applications Buffer The distance By the Buffer operation on a geometric element it is possible to answer value can be questions such as: derived from an attribute How many houses are located within 100 meters of the water pipe? of the points What is the total number of customers within 10 kilometers of the department store? What terrains are involved in the construction of the new road? or provide a solution to problems such as: determination of protected areas around lakes and rivers, extension of pollution zones around motorways, buffer strips around power lines, etc. DICAM DICAM Università Università di Bologna di Bologna Minimum / lowest cost routes Minimum route: shorter or faster? Input data: DTM In determining the fastest path, the GIS can consider The white line represents the impedance associated the optimal solution: lowest with each section (high cost path through a friction impedance → low speed) surface (here raster: DTM). The cost is linked to altitude and slope. The blue line represents the solution to the same problem with a lower resolution DTM. The impedance can be different in different time DICAM DICAM windows (hours of the day, Università Università di Bologna di Bologna potential jams) Determining optimal routes Buffer in a raster domain City limits For a municipal Areas reachable in 5 company, a GIS minutes can plan the routes that 7 different Areas reachable in 10 minutes teams must take every day to collect Other waste. DICAM DICAM Università Università di Bologna di Bologna GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) 5 G. Bitelli  GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) G. Bitelli GIS examples in an urban or GIS examples in an urban or building / infrastructure setting building / infrastructure setting Lederle Graduate Research Center evacuation analysis Building information system Use of GIS tools allowed NASA to find Analysis of distances and ineffective uses of office space and make DICAM walking times from parking DICAM changes to optimize space use resulting in 50 Università lots to offices at MIT Università percent more available office space di Bologna di Bologna Combination of analysis functions: resources allocation From criteria to spatial analysis methods (I) Example: We want to create Problem: in this area locate a new radiological center: the most suitable site for the - within 5 km of the nearest construction of an airport hospital - at least 1 km away from the nearest existing center Criteria: - within 100 m of a road of some importance distance from the city (beyond a minimum limit according to safety regulations and within a maximum limit acceptable to potential - max 50 m from a bus stop users) - in an area intended for in a flat area not subject to flood danger commercial use... ease of access from the main current communication routes DICAM DICAM not in the lake! Università Università di Bologna di Bologna From criteria to spatial analysis methods (II) Suitability analysis with use of weight factors 1 distance from city 2 area with limited slope 3 area not subject within regulatory values to flood danger difference between buffer areas around the DTM: re-classification Analysis of historical city according to the slope data, DTM The final result derives from the intersection (logical AND) of the maps (white areas) derived from the application of the criteria 4 ease ccess from 5 not in the lake main communication routes reclassification DICAM Buffer area around the following a Boolean DICAM Università main routes operation Università di Bologna di Bologna GEOMATICS FOR URBAN AND REGIONAL ANALYSIS (2024/2025) 6 G. Bitelli