Projections and coordinate systems overview projections examples of different projections coordinate systems datums. As described under map projections, traditional coordinate systems are based on a flat coordinate system. That is a very simplistic description of the differences between geographic coordinate system and projected coordinate system but one that should at least. A tissot tissoh indicatrix is a figure that shows how a projection distorts the geometric properties at a point. Gis works with spatial data, and, with using this data that needs to be placed at locations. Spcs was established to support surveying, engineering, and mapping activities in the united states and its territories.
Coordinate systems geographic coordinates latitude and longitude geocentric coordinates x, y, z mass centre of the earth cartesian coordinates datums horizontal and vertical references ellipsoid geoid mean sea level vertical elevation geoid undulation role of gravity map projections properties. Spheroid or ellipsoid based systems, local systems. 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 common geographic framework. With both files in the same projection and coordinate system, you are now ready to do correct overlay analyses. This is changing somewhat as more data are collected by gps. Mercator, which combine a projection algorithm with a system of standardized. Which member countries would be able to afford the costs for changing their system. Coordinate systems, projections, and transformationsproperties of. Projected coordinate systems a map projection is the systematic transformation of locations on the earth latitudelongitude to planar coordinates the basis for this transformation is the geographic coordinate system which references a datum map projections are designed for specific purposes. The employed plane coordinate system is either projected or geographic. Overview of projections and coordinate systems classifying. Setting the coordinate system in commandline is described in maptiler manual.
The course format includes detailed information on how these concepts are applied to different regions of the pacific islands. Understanding coordinate systems and projections for arcgis. Working with map projections and coordinate systems. The definition of the map projection for projected coordinate systems.
The present booklet provides a conceptual introduction to map projections, coordinate systems, and geodetic datums. A projection is the means by which you display the coordinate system and your data on a flat surface, such as a piece of paper or a digital screen. Articulate the leader in rapid elearning and communications. Coordinate systems and map projections, second edition. Projected coordinate systems are derived from map projections and geographic coordinate systems from latitude and longitude degrees. In this example two new zealand coast line layers have been added to arcmap. They are almost always a positive quadrant coordinate system, and are easier to develop and use over a small area. Here is a series of links to help you learn more about applying map projections and coordinate systems in your work. The tutorial booklet entitled coordinate reference systems introduces the mechanics of selecting coordinate reference system components. Pdf georegistration encoding best practice version 2. Geographic and vertical coordinate system tables note. The earth exists in threedimensions but, other than globes, most representations of the earth are two dimensional.
If youve taking the specialization with us, you may recall that we discussed this in the first course, but this will be an indepth, more technical overview of projections and coordinate systems. Why are transformations between different coordinate systems not exact. It is extremely important that you gain an understanding of coordinate systems and map projections. To discuss this subject the joint research centre asked eurogeographics to organise a second workshop in december. When you define the coordinate system for a dataset using the define projection tool or. For remote sensing, gis and surveying has become a key book for many students and professionals around the world. Projections and coordinate systems revisited you must understand this to become proficient in gis different projections for different purposes sometimes you really have to dig for the information. Projections transformation of curved earth to a flat map. Supported linear units, map projections, and projected coordinate systems map projection parameters name sphereonly parameters key below aitoff yes lam0 albers equal area conic lam0 phi1 phi2 phi0 azimuthal equidistant.
Supported linear units, map projections, and projected. The state grids have been merged into countrywide grids. Scroll down to view details of the projection parameters and associated ellipsoids. The coordinate system is one of the most important properties of your data frame. Data is defined in both horizontal and vertical coordinate systems. This quality can be combined with equal area, conformal, and equidistant projections, as in the lambert equal area azimuthal and the azimuthal equidistant projections. James frew esm 263 winter 2020 introducon latude and longitude projecons and coordinate systems. Analytical derivation of some map projections including examples of pseudocylindrical and polyconic projections is also covered. Maptiler automatically loads the coordinate system, unfortunately, in some geodata. Visualisation technical projections and coordinate systems. Page 79 discuss map scale and the basics of coordinate systems.
Where can more information be found about coordinate. Commonly used projections and coordinate systems in bc are utm and bc albers. Coordinate systems and map projections 2nd edition. 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. Projections and coordinate systems may seem complex and arcane to you, but as you become more familiar with gis and gis datasets, you will become more capable of handling different coordinate systems and projections. Based on this, projections can also be categorised in. Projections can be used with different datums projection is a derivate of the datum the main problem with projections. Projected coordinate systems, map projections, parameters, and linear units of measure current as of arcgis version 9. Understanding datums, coordinate systems and map projections.
Learn what a map projection is, why they are used and what impact they have on maps gis systems. The main body of the paper is a detailed derivation of the formulae for a tm projection of the ellipsoid giving x,y coordinates, grid convergence and point scale factor. 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 twodimensional cartesian coordinate plane. State plane coordinate system fips, zones and the fifty states, learn all about the spcs. Introduction much of this basic map coordinates material in these notes may be wellknown to many students in this class. Without a coordinate system a map is just a drawing. The original data has no coordinate system definition the data was collected using a particular coordinate system, but the software has not been told what that coordinate. Understanding projections and coordinate systems important knowledge to have, especially if you deal with many different sets of data that come from different sources. Coordinate systems are referenced to the physical earth surface through the use of datums. Specifying a coordinate systemhelp arcgis for desktop. Buy coordinate systems and map projections, second edition on free shipping on qualified orders. Data from different sources may have different coordinate systems. Coordinate systems, projections, and transformations.
Some basic ideas about the mathematics of map projections. Gis needs to be able to register data from different. The process of converting a threedimensional space to a twodimensional map is called projection. A map projection is a rigorous mathematical means of translating a particular region of our earths curvaceous threedimensional surface into a flat twodimensional representation. Work undertaken in the usa and ussr on the creation of suitable. Other projections minimize overall distortion but dont preserve any of the four spatial properties of area, shape, distance, and direction. This article describes the theory behind datums, projections and coordinate systems, and highlights the importance of using the correct one for a given purpose. Download the list of supported geographic and vertical coordinate systems. The process of projection involves distorition of area, distance, shape, and angles. Optimized automated survey design in wildlife population assessment.
These spatial data include coordinates that define the location, shape, and extent of. Map projections massachusetts institute of technology. Area of use values are in degrees based upon wgs 1984. It determines the map projection for the map display in the data frame. Map scale is concerned with reducing geographical features of interest to manageable proportions, coordinate systems help us define the positions of features on the surface of the earth, and map projections are concerned with moving from.
The data frames coordinate system need not be the same as the data you are using, although if arcmap has to. Understanding map projections, datums, and coordinate systems. A datum is simply a foundation and reference for spatial measurements. A projected coordinate system such as universal transverse mercator utm. Lecture 2 map projections and gis coordinate systems. A map projection is the mathematical transformation of the earth to a flat surface. Select chapter 3 coordinate reference systems on the sphere. Army topographic engineer center report number 7701 telegraph road tecsr7 alexandria, va 223153864 9.
Ellipsoidal coordinate systems reference a mathematically derived spheroidal or ellipsoidal volumetric surface. No matter how you try, the resulting maps always have distortions. The standard international coordinate projection system used with many different map datums. You will need to understand the building blocks of how to define and visualize a location. History, policy, and future directions 1 executive summary the state plane coordinate system spcs is a system of conformal map projections created by the national geodetic survey ngs. Maling gis applications spring 2004 objectives malings assumption. May 05, 2016 where can more information be found about coordinate systems, map projections, and datums. Projections and coordinate systems are a complicated topic in gis, but they form the basis for how a gis can store, analyze, and display spatial data. The shape of the earth and the geodetic datum concept are covered on pages 46. Map scale, coordinate systems, and map projections. Geodesy, coordinate systems, and map projections objectives introduce the main concepts of geodesy coordinate systems, datums, ellipsoids, and geoids describe map projections and coordinate systems we use in gis two key questions what is the shape of. Horizontal coordinate systems locate data across the surface of the earth, and vertical coordinate systems locate the relative height or depth of data. Map projections and projected coordinate systems can be used interchangably as well.
Map projections are introduced on pages 1012, and pages. Oct 08, 20 everything you need to know to work with coordinate systems and projecting data in arcgis. Do all your shapefiles have to be a projected coordinate system in order to calculate geometry. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime.
Handbook for transformation of datums, projections, grids. These are often referred to arcgis 10 what are map projections. Among the most important cartographic considerations are map scale, coordinate systems, and map projections. Background on the geographic coordinate system and map. Objectives coordinate systems and map projections for gis. A global or spherical coordinate system such as latitudelongitude. Coordinate reference system and spatial projection earth. I address this topic because so much visualization is related to the. This selfpaced, online training teaches the fundamental concepts of map projections, datums, and coordinate systems and demonstrates how to use them using esris arcgis. Complicated mathematics to preserve some quantities distortions are inevitable the algorithmic implementation of some projections especially the transverse. Spatial data has coordinate systems, geographic coordinate systems, or projected coordinate systems defined.
It is also recommended to search the web for other useful sites. Do all your shapefiles have to be a projected coordinate. Map projections displaying the earth on 2 dimensional maps the world from space. Although the earth is best represented by a spheroid, the earth is sometimes treated as a sphere. A practical guide to coordinate reference systems, datums and map projections. The objective of this section is to describe and discuss the concepts of map scale, coordinate systems, and map projections and explain why they are central to maps, mapping, and geographic information systems giss. Realizing the synergies nils bohlin, eliot daley, and sue thomson merger and acquisition activity has grown sharply in the last five years. Map projections explained a beginners guide youtube. However each using a different sometimes mathematical approach to performing the flattening resulting in different. Nmap network mapper is a free and open source utility for network exploration and security auditing. Chapter 3 coordinate reference systems on the sphere. Map projections and coordinates a map projection is any method of representing the surface of a sphere or other three. Esm263202002 coordinate systems and map projections. Coordinate systems, map projections, and geographic datum.
Learning the basic properties and uses of coordinate systems understanding the difference between geographic coordinates and projected coordinates getting familiar with different types of map projections managing and troubleshooting coordinate systems of feature classes and images. Background on the geographic coordinate system and map projections outline 1. The gcs tells your data where to draw on the earth, and the projection tells the map how to distort the earth onto a flat surface. How can gnss coordinates be related precisely to the national grid and mean sea level orthometric heights. Coordinate systems and map projections sciencedirect. It is important to know the coordinate system, map units, and spatial projection of the maps that you use and. In summary a coordinate reference system crs refers to the way in which spatial data that represent the earths surface which is round 3 dimensional are flattened so that you can draw them on a 2dimensional surface. Projected coordinate systems, map projections, parameters, and linear units of measure. Visualisation technical positionit marapr 2008 45 i f i ask you where you are, you. Within or on top of the projection is a coordinate system containing the x and y location values, which incorporates the ellipsoid shape of the earth, datum known base values, and units e. Heres the recipe for a projected coordinate system. Changing the coordinate system of a layer in arcmap. Projections and coordinate systems made easy by laurette coetzee, open spatial solutions.
In order to properly display, interpret, analyze, and combine spatial data sets, every dataset. Sep 20, 2019 this selfpaced, online training teaches the fundamental concepts of map projections, datums, and coordinate systems and demonstrates how to use them using esris arcgis. Summary of projected epsg geodetic parameters coordinate. Gis positional data are primarily printed maps which have been digitized. Types of coordinate systems there are two common types of coordinate systems used in gis. Because maps are flat, some of the simplest projectionsare made onto geometric shapes that can be flattened without stretching their surfaces. In the translation from a spherical surface to a twodimensional, flat surface, a. Purchase coordinate systems and map projections 2nd edition. There are many different coordinate systems each one is better for certain purposes. Coordinate systems map transformations geospatial pdf merge multiple. Listed below are map projections relevant to new south wales.
A working manual available online scanned file from the usgs of john p. Mar 16, 2015 there are many different coordinate systems, based on a variety of geodetic datums, projections, and units in use geographic coordinate systems no projection. Measuring distances and areas when your map uses the mercator projection. The web sites listed below provide information on coordinate systems, map projections, and datums. While retaining the benefits of the first edition clear presentation assuming no prior knowledge, a problemsolving approach, practical examples and.
The terms datum, projection and coordinate system are often misinterpreted and misunderstood. The presentation starts by explaining the terminology, and then discusses the details you need to know to actually work successfully with coordinate systems, use the proper projections, and geographic transformations. Horizontal coordinate systems can be of three types. Coordinate systems enable geographic datasets to use common locations for integration. In this third module, were going to start off with talking all about projections. Extension in arcview, and project in arcinfo marylands stateplane coordinate system is based on a lambert conformal conic projection. Learning more about map projection and coordinate system concepts caution. Handbook for transformation of datums, projections, grids qe51ud01 and common coordinate systems 6. To understand how distortion affects a single point on a gis layer, you will employ a tissots indicatrix where a circle on a sphere is projected onto a plane. Pdf coordinate systems and map projections rcz uz on. Area of use values are in decimal degrees based upon wgs 1984. Geodesy, coordinate systems, objectives and map projections. Projections and coordinate systems using corpscon, the projector.
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