As a cartographer with over 25 years experience in the GeoSpatial Industry, I guess I have a slightly more critical eye when I see maps that are produced these days. It makes me cringe when I see maps that are missing some essential items like a scale, north point, legends, projection information or title.
Are these basic elements being lost because it does not matter anymore or is it too easy to just rely on the technology and therefore too easy to overlook the basic elements. I feel it is more about the technology, although I do see there appears to be less importance placed on some of these at some levels of education. Technology has become more than a tool to help us but more and more a tool to do the work for us. I know I do and my spelling has suffered at the hands of technology. Maybe the data was captured at ,, but you are producing a map at , What was the original purpose of the data you are using for your maps?
Have you read the metadata associated with your data, or did it even come with metadata. Too often I see data being used in a way that it was not intended. This maybe due to scale, symbology, attributes or just poor representation. Just because your GIS software can symbolise your data in a certain way, is this really enhancing or degrading the original data. Many maps were a work of art and the essential map elements were there to make it useful to the end users.
But when the Earth has a map projection, this means that it has projected coordinates. For example, the Universal Transverse Mercator system splits the Earth into 60 sections by lines of longitude. If you can imagine you are cutting an orange into 60 wedges, this is how the UTM system works. From here, it assigns the central meridian a value of , meters. When we locate positions on a sphere, we use decimal degrees.
But when we use map projections, we locate positions in meters or feet. A developable surface is the geometric shape that a map projection can be built on. Throughout human history, people have used map projections for a wide range of uses.
Explorers use Mercator maps for rhumb lines to accurately travel in a constant track direction. Actually, the first known map originated in Greece and perceived the world as cylindrical.
Some map projections are useful for some things and other map projections are good for other things. Two of the most common map projections used in North America are the Lambert conformal conic and the Transverse Mercator.
The Lambert Conformal Conic is derived from a cone intersecting the ellipsoid along two standard parallels. The most distortion occurs in the north-south directions. In general, distortion increases away from the standard parallels. For example, this map projection severely expands South America. Even though Google maps used the Mercator projection because it preserves shape decently, and north is always up. But Mercator map projections are really bad at preserving area.
For most of us, the projection is common enough that it looks fine. In reality, Africa is huge on the globe.
The Mercator puzzle game illustrates this point. The location of any point on Earth can be defined using latitudes and longitudes. These points are expressed in angular units such as degrees, minutes, and seconds. Most maps in a GIS are in two-dimensional form. How do geographers deal with distortion? Geographers use maps to show features of the Earth, such as oceans and continents.
But every flat map involves some distortion. To deal with distortions, mapmakers use different map projections. Many projections are named after the mapmakers who designed them. What is distortion in map projection? Similarly, when trying to project a spherical surface of the Earth onto a map plane, the curved surface will get deformed, causing distortions in shape angle , area, direction or distance of features.
Some projections minimize distortion or preserve some properties at the expense of increasing distortion of others. What are the 3 types of map projections?
Three of these common types of map projections are cylindrical, conic, and azimuthal. Why is Mercator projection bad? So while it's great for neatly laying out routes on perfectly straight latitude and longitude lines, its distortions make things closer to the poles appear much larger and shift countries to the wrong regions on the map.
Related Gerardus Mercator revolutionized mapmaking. What is on a topographic map? Topographic maps are detailed, accurate graphic representations of features that appear on the Earth's surface. These features include: cultural: roads, buildings, urban development, railways, airports, names of places and geographic features, administrative boundaries, state and international borders, reserves.
How many types of map projections are there? What is meant by the scale on a map? Map scale refers to the relationship or ratio between distance on a map and the corresponding distance on the ground.
For example, on a scale map, 1cm on the map equals 1km on the ground. What is an Isoline map?
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