‘Learning Ace makes it easier for me focus on what I want to learn and not what the average search engine suggests I should learn.’ 2Below are the properties that can exhibit distortion on a two-dimensional surface: Shape (Conformality). When the scale of a map at any point on the map is the same in any direction, the projection is conformal. Meridians (lines of longitude) and parallels (lines of latitude) intersect at right angles. Shape is preserved locally on conformal maps. Distance. A map is equidistant when it portrays distances from the center of the projection to any other place on the map. Direction. A map preserves direction when azimuths (angles from a point on a line to another point) are portrayed correctly in all directions. Scale. Scale is the relationship between a distance portrayed on a map and the same distance on the Earth. Area. When a map portrays areas over the entire map so that all mapped areas have the same proportional relationship to the areas on the Earth that they represent, the map is an equal-area map. 4. Why Use a Map Projection?* If your spatial data reference locations with decimal degrees (i.e., latitude and longitude), you can display it on your map without employing a projection. ArcMap draws the data by simply treating the latitude and longitude coordinates as planar x,y coordinates. You might decide you don’t need to project your data, however, if you need to make measurements or would like to create an aesthetically pleasing map, you should choose a projected coordinate system. The following are some reasons for using a projected coordinate system: –You want to make accurate measurements from your map and be sure that spatial analysis options you use in ArcMap calculate distance correctly. Latitude/Longitude is a good system for storing spatial data but not very good for viewing, querying, or analyzing maps. Degrees of latitude and longitude are not consistent units of measure for area, shape, distance, and direction. –You are making a small-scale map such as a national or world map. With a small-scale map, your choice of map projection determines the overall appearance of the map. For example, with some projections, lines of latitude and longitude will appear curved, with others, they will appear straight. –Your organization mandates using a particular projected coordinate system for all maps. E.G. please always turn off your cell phone or put it on vibrate mode for class A kind reminder on distractions such as phone use, noise (see syllabus). Please allow fellow students to focus. GIS for environmental management Dr. William James Smith, Jr. Assistant Professor scales. A third type of transformation is the transformation of cartographic objects themselves via their dimensions. Because Learning Ace is a 100% student-focused web destination that leverages our proprietary adaptive search and recommendation technologies and our instructor/publisher relationships to develop an insanely valuable resource to students at each learning point of their coursework. Discover, Browse and Learn. Source.