“Raster” and “Vector” refer to a particular data model A data structure refers to a particular implementation of either the raster or vector model 4 Topology The spatial relationships between things An important distinction between data models and data structures Can be stored or calculated “on the fly” 5 Raster – Vector Data Models Numerous differences in terms of: accuracy storage Section II – Vector Data Model • Overview of the Vector Data Model Vector data models are best suited to geographic entities that have discrete and sharp boundaries. Different types of vector data and concept of topology. GISs have traditionally used either raster or vector for maps. It is a topological vector data model, but compare to the Geodatabase, it is simple and original. Vector data utilizes points, lines, and polygons to represent the spatial features in a map. However, unlike other simple graphic data structures, shapefile polygons are represented by one or more rings. TIN represents the terrain surface as a set of interconnected triangular facets. Figure 3.1 Geographic data can be represented using three basic topological concepts, the point, the line and the area. Topological Structure for Location-based Analyses Raster Topological solitons, a class of stable nonlinear excitations, appear in diverse domains as in the Skyrme model of nuclear forces. The vector data model has since dominated the application of Geographic Information Science, and variants of this model are still in wide use today (Curtin, 2007). Topology rules can help data integrity with vector data models. Lines and boundaries share nodes only if their endpoints are identical. In this model, space is not quantized into discrete grid cells like the raster model. as x,y geographic coordinates Store lines as arcs of connected pts. The Raster Data Model Llano River, Mason Co., TX 5 5 5 5 5 5 5 5 5 5 5 5 2 2 2 2 8 8 5 5 5 5 2 2 8 8 ... (50 m contours, vector data layer) o Resolution of 30 m data is 9 times better than 90 m data ... Topological dependencies = vector or raster . The Data Model A logical data model is how data are organized for use by the GIS. In applied mathematics, topological data analysis ( TDA) is an approach to the analysis of datasets using techniques from topology. List definitions of networks that apply to specific applications or industries. Developed by Esri, shapefiles are now an open format and is a popular option for data transfer. Topology is an informative geospatial property that describes the connectivity, area definition, and contiguity of interrelated points, lines, and polygon. Because shapefiles do not have the processing overhead of a topological data structure, they have advantages over other data sources such as faster drawing speed and edit ability Vector Data Model is an object based approach to the representation of real world features. There are several data models used for vector data such as spaghetti and topological Data formats are based on each data model such as shapefile for spaghetti and geodatabase, coverage for topological data … Two geographic features that share a boundary are called adjacent. There are several algorithms that can be used to visualize vector data. Define the following terms pertaining to a network: Loops, multiple edges, the degree of a vertex, walk, trail, path, cycle, fundamental cycle. Here, we argue that similar excitations play an important role in a remarkable material obtained on stacking and twisting two sheets of graphene. TDA provides a general framework to analyze such data in a manner that is insensitive to the particular metric chosen and provides dimensionality reduction and … The following are types of protocols which help data packets find their way across the Internet: Routing Information Protocol (RIP) RIP is used in both LAN and WAN Networks. Study Lecture 5 (Geographic Data Modeling) flashcards from Kevin Donohue's Portland State University class online, or in Brainscape's iPhone or Android app. Vector data may or may not be topologically explicit, depending on the file’s data structure. The vector model distinguishes between topological and non-topological data structures. Topology is an informative geospatial property that describes the connectivity, area definition, and contiguity of interrelated points, lines, and polygon. Extraction of information from datasets that are high-dimensional, incomplete and noisy is generally challenging. Triangular Irregular Network: a type of topological data structure where all bounded regions are triangles. Geometric Algebra Model for Geometry-oriented Topological Relation Computation Zhaoyuan Yu, Wen Luo, Linwang Yuan, Yong Hu, A-xing Zhu and ... GIS data model (Yuan et al 2011) and the computational framework (Yuan et al. Vector representation of data In the vector based model (), geospatial data is represented in the form of co-ordinates.In vector data, the basic units of spatial information are points, lines and polygons.Each of these units is composed simply as a series of one or more co-ordinate points, for example, a line is a collection of related points, and a polygon is a collection of related lines. An area defined by its Boundary line and by its code is called a polygon. a. coordinate system b. 2.2.2 Shapefile . Data structure Vector model Raster model Georeferencing Projection x-y coordinates Cartesian coordinates Feature Objects Points Lines/polylines Vertex node Polygons Feature Attributes Feature class Themes Layers Vector Models Topological Spaghetti Models Raster Models Grid / matrix Columns / rows Cells / pixels Pixel resolution Discrete Raster vs. Vector Data Model. ESRI Coverage Model HeatherAnn Van Dyke GEOG 575 10‐13‐09 IS a: Georelational Topological Vector Data model Stores geometry and attributes separately Spatial relationships between connecting and adjacent features Uses points and X,Y coordinates Features are represented as points, lines, polygons … Topology in GIS is provided by topological tools. Shapefiles store non-topological vector data along with related attribute data. The full form of RIP is the Routing Information Protocol. This model contains two basic entities, the arc and the node. Vector Data Model To prepare spatial data for computer processing, the vector data model first uses points and their x-, y-coordinates to represent spatial features as points, lines, and areas. Define the following terms pertaining to a network: Loops, multiple edges, the degree of a vertex, walk, trail, path, cycle, fundamental cycle. Shapefile. Topological concepts have been introduced into electronic, photonic and phononic systems, but have not been studied in surface-water-wave systems. An ESRI data format for topological vector data. The GRASS vector model can also store 3D data. On the contrary, lines can cross each other, e.g. The geometry for a feature is stored as a shape comprising a set of vector coordinates. For effective analysis, vector data must be converted into a topological structure. 2) Raster Data Model . Different types of vector data and concept of topology. It is based on R, a statistical programming language that has powerful data processing, visualization, and geospatial capabilities. data. Check out Figure 4.8 in Campbell and Shin. Contiguity is the topological concept, which allows the vector data model to determine adjacency. Raster/grid. Coverage c. Segmentation model d. None of the above 4. True False: Using a topological data structure prevents the repetition of data for lines shared by adjacent polygons. Vector-based Data Raster vs. Vector • Raster: Define objects as arrays of cells • Vector: Define objects as points, lines and polygons Vector-based Data • Simple features • Topological features point line polygon Vector 2. Geographic Data Modeling . Fig. Recall that the from-node and to-node define an arc.