Gis is a computation system capable of assembling, storing. This lecture notes are the authors view on what the basic scientific principles of gis are that everybody should know who wants to use and understand todays geographic information system software. A coordinate system is a reference system used to represent the locations of geographic features, imagery, and observations, such as global positioning system gps locations, within a. Handbook on geographic information systems and digital. The department of geomatics is located at the particular coordinate x,y, or, the department is. A gis provides functionality to capture, store, query, analyze, display and. A geographic coordinate system gcs uses a threedimensional spherical surface to define locations on the earth. A gcs includes an angular unit of measure, a prime meridian, and a datum based on a spheroid a point is referenced by its longitude and latitude values. John snows malaria map is a classic example of mapping out geographic data in order to understand the relationship of a contaminated water pump with the spread of disease.
About cad coordinate systemsarcgis pro documentation. Handbook on geographic information systems and digital mapping. It is a geographic coordinate system which is used to identify locations on earth in meters, as measured in the northern hemisphere going north and east from the intersection of the equator and a central meridian assigned to each of 60 longitudinal zones. There are many different coordinate systems, based on a variety of geodetic datums, projections, and units in use geographic coordinate systems no projection.
Area of use values are in decimal degrees based upon wgs 1984. Coordinate systems and transformationsarcgis runtime sdk. For example, it is usual to build a model in its own modeling frame, and later place this model into a scene in the world coordinate frame. Exploration of spatial relationships among data layers. Therefore, accuracy in a features absolute position and its relative position to. Lecture 1 intro to gis and gis vector and raster data models. Note that the use of a projection defines a cartesian coordinate system and hence cre ates grid north, a third version of the. The crs that is chosen depends on when the data was collected, the geographic extent of the data, the purpose of the data, etc. Datums and geographic coordinate systems 952017 geo 327g386g, ut austin 4 geo327g386g.
The geographic coordinate system great lakes worm watch. This is usually done by defining the zeropoint of some coordinate with respect to the coordinates of the other frame as well as specifying the relative orientation. Gis refers to those spatial information systems that are used for processing and analyzing geospatial data. Many different crs are used to describe geographic data. Coordinate systems can be horizontal, defining where features are across the globe, or. Vector representation vector representation of data in the vector based model figure 4, geospatial data is represented in the form of coordinates.
Project a feature class from a geographic to a projected. All places coordinate reference systems blog blog posts log in to create and rate content, and to follow, bookmark, and share content with other members. However, the software exists and performs many tasks of great use when studying the past. A projected coordinate system based on a map projection such as transverse mercator, albers equal area, or robinson, all of which along with numerous other map projection models provide various mechanisms to project maps of the earths spherical surface onto a. Specify a coordinate systemproperties of maps documentation. Unfortunately, there is some disagreement over what actually defines a gis, with some people even arguing that the term itself is not useful at all.
Note that in arcgis, when projecting data, applying a geographic. Geographic coordinate system the principal geographic coordinate system is wgs 1984, a coordinate system designed by the u. The coordinates are often chosen such that one of the numbers represents a vertical position and two or three of the numbers represent a horizontal position. Coordinate systems are designed for detailed calculations and positioning.
Coordinate system as a part of reference system to describe satellite motion it is necessary to have a welldefined coordinate system. A geographic coordinate system is a threedimensional spherical surface that. Geographic information systems geog 106 academic year. View notes gis class notes geodesy, coordinate systems and map projections from geog 402 at longwood university.
A vertical coordinate system defines the origin for height or depth values. Searchable database of coordinate systems gis lounge. A digital map is generally of much greater value than the same map printed on a paper as the. A coordinate system in which the locations of points in space are expressed by reference to three perpendicular axes, called the coordinate axes x,y,z.
Cartesian coordinates polar coordinates p 2 4 x y 3 5 co o rdinate systems cps124, 296. Maps and scenes use coordinate systems to locate and display data correctly on the earths surface and relative to one another. Therefore, accuracy in a features absolute position and its. On the fly projection is a functionality in gis that allows us to overlay layers, even if they are projected in different coordinate reference systems. We often refer to the modeling frame as the object frame, and the world coordinate frame as the. Spheroid or ellipsoid based systems, local systems. The remote sensing and gis pdf notes rs and gis pdf notes.
There are multiple versions of this course available. Microstation and autocad use 2d and 3d cartesian coordinate systems that locate data at fixed coordinates. The second chapter discusses, inter alia, costbenefit analysis of an investment in digital cartography and gis, plans for census cartographic process, digital map database development, quality assurance, database maintenance, and use of gis during census enumeration. In each coordinate system, geodists use mathematics to give each position on earth a unique. Completion of basics of geographic coordinate systems and basics of map projection s is recommended.
Keeling islands gis are projected coordinate systems based on the wgs84 sphere. X, y, and zcoordinates are not inherently geographic locations. Professor hinton and cowans introduction to gis and cartography. Remote sensing and gis notes pdf rs and gis notes pdf book starts with the topics principle and types of aerial photographs. Geographic information systems have emerged in the last decade as an essential tool for urban and resource planning and management. The field of study that measures the shape and size of the earth is geodesy. Gis analysis for applied economists 1 harvard university. They are ordered in such a way to follow the course outline, but most pages can be read in any desirable order.
Coordinate systems enable geographic datasets to use common locations for integration. For details on how to use this information with arcgis runtime, see spatial references. A coordinate system enables every location on the earth to be specified by a set of coordinates of known location on a grid. As indicated in the files, the lecture notes below are based, primarily or in part, on notes. Projections and coordinate system linkedin slideshare. Geographical information systems gis are computerbased systems that enable users to collect, store, process, analyze and present spatial data. For example, passing geologic and topographic data to an erosion model of the appalachians, or. Follow these instructions to check and change permissions on data files or folders. Geographic coordinate systems and projected coordinate systems. A gis geographic information system is a powerful tool used for computerized mapping and spatial analysis. Gis class notes geodesy, coordinate systems and map.
Geographical information systems gis introduction geographical information system gis is a technology that provides the means to collect and use geographic data to assist in the development of agriculture. There are two major global coordinate systems, know as the geographic coordinate system i. The open source webservice was launch this past march and provides a database of over 6000 coordinate systems used around the world by different gis datasets. Definition of coordinate systems is not a trivial issue due to the irregular. Map projections and coordinate systems gis courses. The order of the coordinates is significant, and they are sometimes identified by their position in an ordered tuple and sometimes by a letter, as in the xcoordinate. These pages are a compilation of lecture notes for my introduction to gis and spatial analysis course es214. The following are two common types of coordinate systems used in a geographic information system gis a global or spherical coordinate system such as.
Instructor combining two gis vector features togetherrequires a process to adopt theattributes of the primary feature. In vector data, the basic units of spatial information are points, lines arcs and polygons. Geographic coordinate systems, datums, spheroids, prime meridians, and angular units of measure current as of arcgis version 9. Introduction to coordinate system definition and realization concentrating on geometric definitions sco web. Coordinate systems the idea of a coordinate system, or coordinate frame is pervasive in computer graphics. When one performs a gis analysis, the user first should ensure the input data are cast in the same coordinate system the output will inherit the same cs. You can give any location on earth latitude and longitude coordinates. A gcs is often incorrectly called a datum, but a datum is only one part of a gcs. Coordinate systems free download as powerpoint presentation. Specify a coordinate systemproperties of maps arcgis pro. Coordinate systems and transformations these pdf documents contain tables of wellknown ids wkids and other details about coordinate systems, datum transformations, and units. There are two different types of coordinate reference systems. In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as euclidean space.
Lecture notes principles of the global positioning. A coordinate system is a reference framework that defines the position of features in either two or threedimensional space. Overview of coordinate reference systems crs in r coordinate reference systems crs provide a standardized way of describing locations. It is the central mathematical element of more complex issue. Geographic coordinate systems pdf format projected coordinate systems pdf format geographic transformations pdf format. In other gis applications this may be called projecting on the fly.
If you need a consolidated place to search for coordinate systems, epsg. The issue of scale defines a fundamental difference between how gis and cad systems utilize coordinate systems. Any time you see an option to define the coordinate system, you should. Geodesists use coordinate reference systems such as wgs84, nad27 and nad83. For example, if you merge two addresses together,say, 10 and 12 main street, you can chooseto take all the attributes from 10 main streetas the primary data source for all those attributes. Gnss processing services and geographic information system gis analysis tools. Coordinate systems latitude cartesian coordinate system.
Computer graphics 2d geometric transf orms p age 1 a b d x y x y t ransfo rmations cps124, 296. Coordinate systems, map projections, and geographic datum. Coordinate systems can be horizontal, defining where features are across the globe, or vertical, defining how high or deep features are relative to a surface. A geographic coordinate system is a coordinate system that enables every location on earth to be specified by a set of numbers, letters or symbols. Recall the event theme you created in lab during week 2. Coordinate systems can be defined in both maps and scenes. Below is an example of a map that uses a geographic coordinate system. It provides an electronic representation of information, called spatial data, about the earths natural and manmade features. Plane coordinate systems are typically used in largescale mapping such as a scale of 1.
Coordinate systems a particular kind of reference frame or system, such as plane rectangular coordinates or spherical coordinates, which use linear or angular quantities to. Lecture notes a workshop on geographic information. If you have data that has a coordinate system called. There are two common types of coordinate systems used in gis. Introduction to gis workbook university of maryland. Gis is usually taken to stand for either geographic information systems or geographic information science.