Spatial database systems and geographic information systems as their most important application aim at storing, retrieving, manipulating, querying, and analysing geometric data. Classification methods for spatial data representation. Accordingly, gis technology utilizes two basic types of data. A commonperhaps modalrepresentation of geography in spatial analysis and geographic information systems is native unexamined objects interacting based on simple distance and connectivity. Pdf classification methods for spatial data representation. We will use the term layers from this point on, since this is the recognized term used in arcgis. A new spatial data representation in gis zukuan wei 1 sookkyoung cho 1 jaehong kim 2 haeyoung bae 1.
It is in this light that gis is presented in this chapter. Wentz department of geography, university of utah department of geography, arizona state university. Geographic representation in gis flashcards quizlet. Data types the data model represents a set of guidelines to convert the real world. Jun 06, 2017 data models in geographical information system gis 1. Vector representation vector representation of data in the vector based model figure 4, geospatial data is represented in the form of coordinates. Introduction to gis learning objectives what a gis is what you need to set up a gis basic mapping terminology how gis technology can help you produce maps and other information. Introduction to gis and spatial data vector and raster comparison vector raster compact data structure for homogenous areas.
Spatial data are often referred to as layers, coverages, or layers. Can overlay displays easily can easily manipulate data table can have many variables linked to one geographic file better suited for map output a simple data structure. Only in this way, the student can abstract from the peculiarities of a particular system and open hisher mind to. Representation and spatial analysis in geographic information. In fact, most users are dependent on one another for portions of the data they want to use. These characteristics can be quantitative andor qualitative in. The processes of data collection are also variously referred to as data capture, data automation, data conversion, data transfer, data translation, and digitizing. It is the intention to teach the principles of gis independent of any particular software system. Provide the data analyze the data select the best data further information about collecting data can be found in the module basic data capture. Pdf it is necessary to classify numerical values of spatial data when representing them on a map and visually understanding it. Methods for gis manipulation, analysis, and evaluation 146 overview this chapter details the methods that the team used to 1 evaluate lands within the study area, 2 delineate conservation focus areas cfas, and 3 prioritize individual, privately owned land parcels for protection. The geographers, economists, resource scientists and the decision makers use a lot of data these days. Most gis software applications mainly focus on the usage and manipulation of vector geodatabases with added components to work with rasterbased geodatabases.
Real world data model data structuremachine code geodatabase native data structure for arcgis and is the primary data format used for editing and data management. Introduction to gis basics, data, analysis case studies. Data types in gis the data in a gis can be classified into two main categories. Attribute data generally defined as additional information, which can then be tied to spatial data. Geographic information technology training alliance gitta. Index introduction components of gis data types in gis data representation raster data model vector data model differences between raster and vector triangulated irregular network tin digital elevation model dem conclusion reference. Raster data model each grid cell in a raster data layer is one unit the minimum amount of information in the raster data model every cell has a value, even if it is a special value to indicate that there is no data or that data is missing at that location the values are numbers, either. Spatial data describes the absolute and relative location of geographic features. Research has shown that special data types are necessary to model geometry and to suitably represent geometric data in data base systems. Gis a geographic information system integrates hardware, software, data, and people to capture, manipulate, analyse and display all forms of geographically referenced information or spatial data.
Each representation has merits and is suited for particular kinds of information and analysis. They are the result of more than 20 years involvement in gis and spatial data handling. Every house, every tree, every city has its own unique latitude and longitude coordinates. Taking the raster data model first, it represents space as a continuous field consisting of squares called pixels of a standard size, like the picture on a computer monitor or tv screen. The basic data types in a gis reflect traditional data found on a map. However, gis provide a useful framework for handling geographical data and for performing basic operations. In the vector data model, attributes are stored in table fields. An overview of how the real world is decomposed and stored digitally in the computer, what are spatial data models, specifying the vector data. How gis represents and organizes geographic information. Introduction to geography, gis, spatial data and use of gis. Solving spatial problems with representation and process. Gis software can quickly draw a range of maps from your data, making it easy to pick the most appropriate map for your enquiry question and for the data type and location.
Such data handling and analysis can be seen as a precursor, necessary to subsequent statistical and analytical analysis of the data, perhaps outside the gis. But what is the difference between raster and vector data. Besides the tabular form, the data may also be presented in some graphic or diagrammatic form. Whats the difference between gis spatial data types. Every functionality that makes a gis separate from another analytical environment is rooted in the spatially explicit nature of the data.
Gis layers can be combined from many sources and many users. The huge amount of spatial data generated by gis geographical information systems expansion, the increasing number of geographic informatics applications available, the computerization of a. Pdf techniques for statistical data visualization in gis. These characteristics can be quantitative andor qualitative in nature. Simple data structures overlay and combination of maps and remote sensed images easy some spatial analysis methods simple to perform simulation easy, because cells have the same size technology is cheap disadvantages of raster data structures. Spatial data spatial data are data that have a spatial component, it means that data are connected to a place in the earth.
Spatial data entered into a gis always fits into one of two main data structures, being either raster or vector data. Representation of data the data describe the properties of the phenomena they represent. Types of gis free download as powerpoint presentation. Representation and spatial analysis in geographic information systems harvey j. One key aspect of gis is that it provides a sophisticated series of operators that work against the georeferenced collection of data layers.
Spatial data can be collected from primary sources such as field measurements, or from secondary sources like existing gis datasets. They are collected from a variety of sources chapter 1. Data are usually represented by numerical values, alphanumeric characters, logical values, etc. Using gis maps are a powerful technique for representing spatial relationships, but they can take a long time to draw by hand. Representation models are sometimes referred to as data models and are considered descriptive models. There are three common representations of spatial data, used in gis, namely. Along with establishing the spatial relationships, the gis representation model is also able to model the attributes of the objects for example, who owns each building. Types of gis geographic information system scientific. Think of geographic representation in gis as a 4 step process.
The two primary types of spatial data are vector and raster data in gis. Data structures for networks what do we expect to do with a network. Find out more on the spatial data models commonly used. Information data structured, formatted, converted and modelled to become meaningful to a user. The basic data type in a gis reflects traditional data found on a map. Data types and map types much dictated by continuity, data level and dimension of data map type should be appropriate for data type have covered classification methods and graphics methods exist to optimize classification, statistically and visually classification can impact map message, perception and interpretation. The gis spatial data model university of washington. When should we use raster and when should we use vector. Lecture 1 intro to gis and gis vector and raster data models. Within the spatial referenced data group, the gis data can be further classified into two different types. Attribute data or nonspatial data describes characteristics of the spatial features. Data types in arcgis in a gis software, such as arcgis, data types refer to the attributes in the vector data model and cell values in the raster data model. This chapter describes the data sources, techniques, and workflows involved in gis data collection. Spatial data spatial data in gis represents features that have a known location on the earth.
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