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Welcome to this course on Geo Spatial Analysis In Urban Planning. We are in the 1stmodule, the module is structured as Introduction to Geographic Information System andGeographic Distribution. So, in the 1st lecture of this module we are going to focus mainly onthe components of geographic information system and what this geographic informationsystem is all about. So, we are going to have a very brief look on a GIS Information System,Geographical Information System.
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So, the concept that would be covered in this particular lecture is a brief or an over view ofthe GIS, the component components that constitute GIS, the functions of GIS and theapplication of GIS.
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So, if we see the kind of applications that your GIS would have on the urban scape, we wouldneed to know about what this GIS is all about. So, basically if we see the definition it includescomputer system which basically would capture store, manage, analyze and the display allkinds of geographical or spatial data and it would run the queries and display them as maps.
And it has the data which is aggregated in a locational reference frame work or a kind of alocational reference system such as the data would be having your latitudinal or longitudinalcoordinates or it might be having easting or northing in terms of meters or any distance
measure. Now, the objectives of GIS is basically to aid in increasing the efficiency ofplanning and decision making process.
We make lot of I mean planning judgments based on given scenarios, based on the existingdata and we interpreted and which basically leads to particular solution to a given problemand GIS is a very effective tool in this particular process. Secondly, it provides an efficientmeans of data distribution and data handling.
So, we know in today’s world I mean we have to handle I mean a humongous amount of data,so to handle it efficiently a we need a system which can do it real time, which can process thedata real time. So, basically this particular system of geographical information systemprovides us with a platform for, I mean efficient way of handling the data and processing it inreal time.
The next objective of GIS is to eliminate redundant data base and minimize duplication. So,in today’s world we see that the same data is available from different sources. So, there couldbe redundancy in terms of the data that we might collect. So, we are talking about big data,we are talking about IoT systems wherein the sensors would be aiding in the processes of datacollection.
So, there could be I mean redundancy in terms of the data base that we collect and there couldbe duplicity of the data. So, basically GIS system should do away with this kind of aduplication in terms of the data collection and it is archival, so that is also one of theobjectives to eliminate the redundancy in terms of the data that we collect.
The next objective is to integrate information from multifarious sources. So, basically whenwe are talking about urban systems, we are not just talking about individual components inisolation, but we are talking about multitudes or difference sources wherein information isrequired and it gets collated into this given system. So, it should be able to integrate all thedata from different sources.
So, when we talk about integration of the data we have to look into the temporal integrationthat is the data that you collect at different time points, we have to talk about scalability ofthis particular information at what scale you we are collecting this information. So, thissystem has to integrate all the information that is available from different sources,multifarious sources and integrate it in one platform. And it is very important to mention thatall this data would be having locational reference, otherwise it would be I mean not so usefulfor our analysis and decision making.
The last objective that we can gauge for this particular system is to develop analytical modelshaving queries of the data that we have collected in our, I mean we were talking aboutdifferent sources where we can collect data for urban systems. So, this geographicallyreference data that we had collected needs to be analyzed and these analysis could be verycomplex analysis or it could be simple queries.
So, this system should be I mean robust enough to run complex analysis as well as simplequeries and it should be able to do it in real time and display it as maps which would be easyto interpret.
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Now, if we look at the different components of GIS. The first component is informationsystem on computer that is part of the hardware, then we would be having softwares whichwould be involved in doing the data processing part, collating the data, analyzing, I meangiving as a programming tool to basically write codes, to run processes, do simulations.
The next important most important component of GIS is the data base. So, we have talkedabout the multifarious data base that is required for any sort of an urban analysis which iswhich would have a geographical reference. So, this data base would be pertaining todifferent types of variables and the last but the most important component are the people.
Basically, when we are talking about urban planning we are dealing with planning issues thatare pertinent to the people who are occupants of that particular place. So, people is I meangetting information regarding the people and their feedback, their apprehensions, their I mean
aspirations, it becomes part of the planning process. So, the last component of the GISinformation system is the people.
If we talk about the history of GIS how this came into be. It was Dr. Roger Tomlinson who in1962, he created and developed the Canadian Geographical Information System, the CGIS orthe Canadian Land Inventory System. It was basically a land record system in which hecreated a frame work which can be used for basically I mean recording the inventory of theindividual parses, its usages and the various other related parameters in such data base. Andinterestingly Dr. Roger Tomlinson prior to doing this particular work he was a fighter pilot inthe royal air force.
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Next, if we see the different types of data formats that we use in this particular data base wehad talked about the different components of the GIS and data being one of the most
important component. So, it is important for us to store the data in different formats. So,primarily there are two different types of data formats that we use to store data.
The first type is the raster data, you most of you are familiar with raster data, when we takepictures using our cameras, mobile cameras or cameras we generally I mean take thereflectances and record them as pixels. So, it is a grid or series of grid cells wherein each gridcell would be a value representing the features that are being observed. So, we basicallyrecord the reflectances as digital numbers and basically it is stored as an array of grid cellswhich is recorded as the raster data.
Now, this particular type of data GIS data is best suited for acquiring continuous data,wherein you are not basically interested in containing I mean you are recording pointinformation, but a continuous data an information that would not have hard boundaries orlocation. So, I mean as an example we can say when we want to acquire the temperature,values of all the grid cells in a given city, say suppose we are doing a study on the urban heatislands, we would be interesting in capturing the temperature values.
So, the raster data format would be ideally suited to do such an analysis. Next example couldbe of elevation of a given area, wherein if you want to find out the kind of run off in case ofan urban flood. So, the elevation could be stored in for each and every point and we can thereafter convert it into either contours or we can find out the slope map, we can find out theaspect map. So, that could be another example where we could record the data, thecontinuous data as raster data point.
The next type of data that are basically used in GIS and which is extensively used are vectordata. So, vector data, I mean we have been using vector data in CAD systems, wherein thedata basically is recorded as points, lines or polygons. So, we in this particular data framework, we record the discrete data which is represented as vector.
So, this data would have exact location or hard boundaries and these would I mean entail theboundaries of say administrative boundaries or if you are acquiring the linear data points orlines line information, examples could be that of road the point data could be stored I mean
for bus stops in a given urban area. So, this could be some of the examples of data whichcould be stored in vector format, specifically as polygons, as lines or as points.
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Next, we talk about the different types of raster data formats in which we would be storingdata GIS data. So, first data format is the Arcinfo Grid Data Format which is commonly usedand basically it is the proprietary format of Esri and it is comprised of two folders, wherein aworkspace would contain multiple files and it would carry a folder which would have thename of the grid and it would carry number of various adf files which would have thereflectance for each of the pixels or the values of each of the grids aggregated as Arcinfo grid.
The next image types would be Multi band image formats and there are different types offormats in this. The main major formats that are used for this type of raster data are the bandinterleaved line format, the other formats are band interleaved pixel and band sequential. So,
in this three types of formats we would be able to store multiple bands of information ormultiple layers of informations, not just three layers as we see in photographs mostly the red,green and the blue bands.
So, here we can store multiple bands. So, this would be very useful when we are acquiringimage or data from multiple sources. The next type of raster data format is Digital ElevationModel. It is I mean very popularly known as DEM, which is used by USGS to record theelevation of point features on the earth surface. So, this also is an example of continuous dataand it is stored as raster data point format.
The next data type the raster data type is GeoTIFF. So, this is basically a tagged image fileformat in which it is geographical geographically referenced. So, the image in its headerinformation would have the geographical extents as the part of the file.
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Now, we would have other popular raster data formats while we are dealing with GIS. Someof these formats are ADRG format, it is Arc Digitized Raster Graphics. RPF format that isRaster Product Format, it is I mean in the military domain, this is often used. We have theDRG format, which is the digital raster graphic. ECRG format which is the acronym forEnhanced Compressed ARC Raster Graphics.
ECW format which is enhanced compressed Wavelet format which is a ERDAS format. Esrigrid format, which is ASCII raster format used by ESRI, we have already talked about it. Wehave already talked about the GeoTIFF format which is enriched with TIFF file enriched withGIS coordinates. HDF format which is the hierarchical data format files.
IMG format which is the image file format used by ERDAS. We have the Joint PhotographicExperts Group committee the JPEG format and it is popularly known as the JPEG2000format which uses the discrete wavelength transformation for compression. And then we havethe MrSID which is the multi resolution seamless image database.
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The next data format is the vector data that we extensively use in GIS to record basicallydiscrete data points. So, the most commonly used file format is the shape files and this fileformat is mostly compatible with most of the GIS softwares either proprietary or open sourcesoftwares that you would come across.
So, this particular file format has a group of files associated with it and the file name wouldhave different types of prefixes such as dot shp which is the shapefile wherein the datacontent is there, shx which deals with the header and has the meta information regarding thefile. You would have the associated database information in the dot dbf format. Theprojection file which records the geographical projection of the database which is recorded ina dot prj format and then we would have dot lyr files which are basically layer files.
The next vector data type is the Arcinfo coverage which is nowadays which has been replacedby geodatabase format and it is comprised of two folders within a workspace. The first folderhas the name of the coverage and contains a number of adf files and the second folder is theinfo folder which contains dot dat file and dot nit files which basically contain the data baseinformation regarding the vector entities.
The next type of vector data format is the geodatabase information and it is the native dataformat for ESRIs, ArcGIS software. So, basically it is a collection of GIS data sets of varioustypes, I mean it could be vector, raster or tabular data and this is aggregated as geodatabase.
We also have I mean data from LiDAR sensors, that is Light Detection and Ranging sensorswhich are basically pulsed laser to measure the range values that is the distance values andwhich would give you the variable distances to feature objects and this information is storedas point cloud information and this file generally is has a extension of dot LAS, LAS.
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Now, other popular vector data formats are AutoCAD DXF. So, this is the format byautodesk and this is either in a binary format or it is in a ASCII format. So, if you have a DXFASCII format you can very well open it in a notepad or a WordPad and see the contents ofthat file how the data values are stored for point entities, for line entities or polygon entities.
Next we have the Cartesian coordinate system which is simple point cloud. The DLG that isthe Digital Line Graph which is basically a USGS format, it is extensively used by USGS.GML format which is the Geography Markup Language, it is a open GIS format used forexchanging GIS data. Also we have GeoJSON format which is the light weight format basedon JSON which is used in many open source GIS packages. So, this two formats are veryuseful for us this GML and GeoJSON formats.
The next one is the proprietary format which is GeoMedia, it is Intergraph’s Microsoft accessbased format, for I mean specifically the vector storage, data which are of vector types. Wehave the ISFC format which is Intergraph’s MicroStation based CAD solution. We have theKML format which is I mean extensively used by Google. It is known as the Keyhole MarkupLanguage which is the XML based language for storing vector information.
We have MapInfo TAB format, again this is proprietary format. This is the MapInfosoftwares vector data format. We have the National Transfer Format NTF. We have Spatialiteit is a spatial extension to the SQLite, it is again a open source format. We have simplefeatures which is specification for vector data. SOSI format which is spatial data format usedfor most of the public exchanges and this is used in Norway.
We have the spatial data file which is the autodesk’s high-performance geodatabase format.We have TIGER format, which is Topologically Integrated a Geographic Encoding andReferencing. And we have the VPF format which is Vector Product Format. These are someof the I mean proprietary and open source format which are extensively used while collatingor handling vector data information.
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So, now let us see what could be the uses or applicability of geographical information systemand it could be in various context. But we will focus more on the urban applicability of GISspecifically for issues related to urban planning. First is to basically create the data base tohave an inventory of the data, which would be basically point specific, location specific andwe would also be able to code the relationships between the feature data. So, we would beable to determine the casualty of an event in a urban area.
Second, would be to assess the intensity of the features. Now, say suppose let us take anexample of an urban area say suppose we have a urban area, wherein we are talking aboutdifferent wards, it may have different I mean types of, I mean the number of population, itwould have different attributes related to say economy or say educational attainment or theratio of male to female, the amount of working population. So, these attributes can be added
to or tat with the vector data types and could be stored. So, it could be used to assess theintensity of different features in a given area.
Next is to assess the density of the features. So, we can gauge the intensity of these featuresper unit area. Say for example, we can calculate the population density in different wards andfind out what is intensity of development in different areas. So, similarly I mean in a givenurban area we could see that some of the wards are would have high raised buildings, some ofthem would have slums, some of them would have low raised structures, so we could we canidentify the intensity of development or the development density using GIS platform. We canalso monitor the changes that would happen over time and monitor the growth of a given cityin a temporal frame work.
So, in this context the remote sensing images, I mean this images are generally stored asraster data format, so they provide us with valuable resource when we want to monitor thetemporal changes that happen in the urban context. So, we could work on urban sprawl basedapplications to see the zones where the urban growth is fast and take necessary measures forproviding infrastructure and services in these areas, the temporal modeling or temporalchanges and we can also preclude growth; I mean we can do I mean simulation based on thehistorical growth transacts and we can also portray how the city might be growing in future.
So, we can also do a kind of a projection. So, we can monitor the temporal changes and wecan also predict temporal changes using different modeling approaches. Then we can monitorthe status of in an area of interest. If we have flood in a given area we can identify the areaswhere flooding has happened and we can enlist the number of villages or the wards or thetotal population that is affected by this flood event. So, we can monitor the status in an area ofinterest.
We can create a area of interest which is generally referred to as AOI in common parlance ofGIS and we can find out what is the status or monitor the I mean how things exist, what is theI mean condition of the people, what are the condition of the infrastructure and I mean
different aspects of urban services. So, this monitoring can be done in a area of interest basedstudies.
We can also do proximal studies finding your say land used along different road segmentsusing buffering. So, I mean what lies in proximity to say given features can be studied usingGIS, specifically in the context of urban planning.
We can also model complex scenarios and simulate complex scenarios, I mean I was justtalking to you regarding modeling urban sprawl, we can also model complex scenario such asair pollution. And we can use physical models like Gaussian plume model or say I mean linesource pollution models or area source pollution model or point source pollution models insimulating these kind of deposition the air pollution deposition, and I mean identifying theareas which are prone to such kind of pollution.
Another example that comes to my mind is areas prone to seismic hazard. So, from I meanour understanding of the parameters which affect seismic events, we can find out the factorswhich contribute to the seismic hazard in given areas and we can study areas and we canisolate and identify areas which are prone to seismic hazards. So, these are some of theexamples and uses of GIS.
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So, this comes, I mean with this we would conclude this particular first lecture of this series.For your reference you can go through these two books which are enlisted here by PaulBolstad and by Kang-tsung. And the second book is very fundamental book and it would, Imean help you getting through the ropes of learning GIS.
Thanks, for this I mean for the your patient hearing.
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