A map projection is a rigorous mathematical means of translating a particular region of our earths curvaceous threedimensional surface into a flat twodimensional representation. Scale distortions on maps are shown on the map by an ellipse of distortion or using scale factor which is the ratio of the scale at a given point to the true scale. Rightclick the dita map folder, and from the menu that displays, click open map editor. Because there is no limit to the number of possible map projections, there can be no comprehensive list. The edges of equatorial projections are determined so as to put the maps audience at the centre of the map. This is a digital copy of a book that was preserved for. The central focus of this book is on the theory of map projections. Every distinct map projection distorts in a distinct way. Learn about the differences between dita maps and bookmaps.
Adobe techcomm blog all about output from dita maps with. Dita maps are documents that organize topics and other resources into structured collections of information. Dec 27, 2002 a map projection is one of many methods used to represent the 3dimensional surface of the earth or other round body on a 2dimensional plane in cartography mapmaking. As suggested by its name, a topicref is simply a reference or a pointer to a topic stored in a separate file of its own. What is a map projection map projection definition. A dita map is basically a sequence of possibly nested topicref elements. Map projection concerns the science of mathematical cartography, the techniques by which the earths dimensions, shape and features are translated in map form, be that twodimensional paper or two or three dimensional electronic representations. Dec 01, 2010 the dita specification provides specialized map types. We encourage you to complete the other classes before taking this class. A map projection is a geometric function that transforms the earths curved, ellipsoidal surface onto a flat, 2dimensional plane. In the translation from a spherical surface to a twodimensional, flat surface, a change in the expression of points occurs. Maps consist of references to topics, maps, and other resources organized into hierarchies, groups, and tables.
A dita map describes the relationships among a set of dita topics. However, instead of projecting a light, cartographers use mathematical formulas to create projections. An album of map projections should enable read ers to sharpen and in some cases to correct their knowledge of the distances, directions, and relative areas of the world. Bookmaps are used to describe page layout publishing outputs such as books, articles, manuals and research papers. Read it properties of the map projections explaining the properties assigned to map projections. Therefore a map projection must have been used to create the map, and, conversely, maps could not exist without map projections. This course builds on what you learned in the four preceding classes. Although there has been no dearth of valuable books describing a wide range of map projec tions, an album of map projections is the. Use the printable worksheet to pinpoint study points to look. The study of map projections is the characterization of these distortions.
A scale tells you the ratio of a distance on the map to the actual distance in real life. Sep 20, 2015 description of three different types of map projections. This fourlesson course introduces you to dita maps and bookmaps. Several common projected coordinate systems are discussed on pages 2021. Similarly constant local scale is maintained in every direction around a point. Page 22 covers use of map projections in group display.
If we were to place a light bulb inside a translucent globe and project the image onto a wallwed have a map projection. In conformal map projections also known as orthomorphic or autogonal projection local angles are preserved. A datum provides a frame of reference for measuring locations on the surface of the earth. The comment about the facility location in relation to the lambert standard parallel lines versus utm makes sense. Mar 31, 2017 data from vector, raster, and elevation data from common gis and raster formats can be used as inputs. These placeholders instructs the dita processing software to automatically. Bookmaps are a specialisation of the base dita map information type. Map projection definition of map projection by the free.
This process is typically, but not necessarily, a mathematical procedure some methods are graphically based. Planning for dita provides insights into how to most. Countries close to the equator barely change, whereas countries further north shrink dramatically. Like ditamaps, bookmaps are containers for structure and context metadata, and do not contain any content. The package also includes a stylesheet for merging all the documents referenced by a map into a single dita. Page 79 discuss map scale and the basics of coordinate systems. Since the earth is roughly the shape of an oblate spheroid, map projections are necessary for creating maps of the earth or parts of the earth that are represented on a plane such as a piece of paper or a computer screen.
The package also includes a stylesheet for merging all the documents referenced by a map into a single dita file. The dita map and map group domain elements organize topics into hierarchies, groups, and relationships. They contain information structures that are specific. Topics and maps takes you through the building blocks of dita.
Beginning almost two thousand years ago with marinus and ptolemy, map projections have played a very significant role in cartography. Except where otherwise noted, images on this site are by tobias jung and are licensed under cc bysa 4. Purchase coordinate systems and map projections 2nd edition. Resources for further study are presented on page 23. Like ditamaps, bookmaps are containers for structure and. Sep 21, 2008 a map projection is a mathematical model used to make the map. Map projections are designed for specific purposes. European maps put the bering strait at the edges, australian and asian maps the atlantic, american maps break asia in two. A map projection is a method for taking the curved surface of the earth and displaying it on something flat, like a computer screen or a piece of paper. The dita package includes xslt stylesheets that enable you, with a single command, to transform all the documents referenced by a map to html and build a table of contents that links to all of them. Latitudes and longitudes are expressed in degrees, minutes and seconds.
Projection wizard is a web application that helps cartographers select an appropriate projection for their map. It has survived long enough for the to expire and the book to enter the public domain. Only the title parameter is displayed, and we dont want to but the info in the fos. The dita map displays in the document structure pane in the dita map editor of the astoria workbench. While generating output form a dita map, print attribute value shall be used to determine whether the topic shall be included in the output. Map projections designed for smallscale data are usually based on spherical rather than spheroidal geographic coordinate systems. Every map projection has its own advantages and disadvantages, as it is impossible to project a 3d surface onto a 2d surface without distorting the image in some fashion. A bookmap is a special kind of dita map that defines the major structures and setup information for producing maps of information as a book. However, map projection refers specifically to a cartographic projection. You dont need to create a for the screen media and a for the. Introduction to dita, the dita concept topic type, the dita task topic type, and the dita reference and glossary topic types. A map of the earth is a representation of a curved surface on a plane. Dita maps specify hierarchy and the relationships among the topics.
Models of map projections there are two models for creating different map projections. There is no limit to the number of possible map projections 1 projections are a subject of several pure mathematical fields, including differential geometry, projective geometry, and manifolds. This book essentially displays a whole lot of different map projections, those formulations by which the curved earth gets represented on flat paper. It no longer works, unless i am,again, missing something. And whats this lenticular class, never heard that one before. The map element describes the relationships among a set of resources, such as dita topics. But then we have 2 problems, i cannot find where to format the the chapter title, and when i use topic headings on level 3 of the map they are not rendered properley, they appear at the end of the.
One map projection might be used for largescale data in a limited area, while another is used for a smallscale map of the world. Flex projectorinteractive software for designing world map projections. This is a summary of map projections that have articles of their own on wikipedia or that are otherwise notable. I believe the north american lambert conformal conic projection im using has standard lines that are centered somewhere in the middle of the u. Sep 26, 2017 a world map tells a lot about the person who has made it, or about the market it is made for, says frans blok. Improve your knowledge of map projections in this interactive quizworksheet combo. The dita specification provides specialized map types. Sep 29, 2011 this video describes what map projections are, and how the earth can be represented using map projections within a gis. Projections by presentation of a metric property would include equidistant, conformal, gnomonic, equal area, and compromise projections. A day in the life of a dita author helps to illustrate how an author would develop a content outline, create topics and write structured content. It defines the origin and orientation of latitude and longitude lines. Dita maps have unique attributes that are designed to control the way that relationships are interpreted for different output purposes. There is a detailed paper published in cartographic perspectives 2008 which describes flex projector.
While its well known that the mercator projection distorts the world, the maps here show very clearly by how much. A dita bookmap is a useful variant of a map in which some specialized topicref elements. These methods enable map makers to control the distortion that. A typical dita map might have a title and then a set of topicrefs, in a sequence, in a hierarchy, or both, that define the structure by which topics are to be viewed as a complete information deliverable. A strange map projection euler spiral numberphile duration. Apr 25, 2017 however, map projections have distortions which depend largely on the size of the area being mapped. Common coordinate system and map projection tasks in arcgis. Coordinate systems and map projections 2nd edition elsevier. Depending on the extent and the distortion property of the map, the application returns a list of appropriate map projections with additional projection parameters if necessary. This example creates a map using the gallpeters projection, rather than the default mercator projection. Map makers have devised methods for taking points on the curved surface of the earth and projecting them onto a flat surface.
973 678 1303 539 389 815 302 1321 281 131 432 950 1353 1023 1296 823 1084 950 488 855 550 257 208 218 875 1157 1430 83 526 1235 1418 1397 627 25 195 354 376