"In cartography, a map projection is any of a broad set of transformations employed to represent the curved two-dimensional surface of a globe on a plane."
The way that a three-dimensional world is transformed into a two-dimensional map, using mathematical formulas.
Coordinate systems: Understanding the different types of coordinate systems used for spatial data, including geographic (latitude and longitude) and projected (Cartesian coordinates).
Geographic information systems (GIS): An introduction to GIS and the tools used for spatial analysis, such as ArcGIS and QGIS.
Vector data: A type of spatial data that represents points, lines, and polygons using coordinates.
Raster data: A type of spatial data that represents continuous surfaces, such as elevation or temperature, using a grid of cells.
Projections: A mathematical transformation used to convert geographic coordinates to projected coordinates, allowing for accurate measurements and analysis.
Map projections: A method for representing the curved surface of the Earth on a flat map, including popular projections like Mercator and Robinson.
Spatial relationships: Understanding how different spatial features relate to each other, including proximity, adjacency, and connectivity.
Spatial statistics: Analyzing spatial data using statistical techniques, including spatial autocorrelation and clustering.
Spatial queries: Using SQL or other tools to extract specific subsets of spatial data based on location or other criteria.
Geocoding: Converting textual addresses into geographic coordinates to allow for spatial analysis.
Network analysis: Analyzing networks such as road networks and transportation systems to understand their characteristics and efficiencies.
Spatial data visualization: Creating maps and other visual representations of spatial data to communicate patterns and insights.
Spatial modeling: Using mathematical models to simulate and predict spatial phenomena, such as population growth or ecological change.
Spatial data quality: Understanding the sources of error and uncertainty in spatial data and methods for improving data quality.
Spatial data infrastructures: The infrastructure and standards used for managing and sharing spatial data, including the Open Geospatial Consortium's standards.
Point: A data projection that displays data using individual points or symbols. Each point represents a single location or object.
Line: A data projection that displays data using lines or arcs. Each line or arc represents the connection or route between two points.
Area: A data projection that displays data using shaded or colored polygons. Each polygon represents a geographic area or region.
Heat Map: A data projection that displays data using colored grids or patterns to represent the density of a certain variable. This is useful when analyzing patterns of usage, traffic or other attributes.
Choropleth: A data projection that displays data using colors or shading to represent different intensities of a variable over geographic regions.
Isopleth: A data projection that displays data using contour lines or isolines to represent data values.
Voronoi: A data projection that divides a geographic area into regions called Voronoi polygons. These polygons are created by connecting the data points that are nearest to each other.
Network: A data projection that represents data using a network of lines and nodes. This is useful when modeling transportation routes, communication networks or other types of connected systems.
Hexmap: A data projection that divides an area into hexagonal shapes. The size of the hexagon is usually determined by the density of data.
Topographical: A data projection that displays data in relation to the elevation or topography of a geographic area. This is useful when analyzing terrain datasets, infrastructure planning, or predicting natural disasters.
3D: A data projection that displays data in three-dimensional space. This is useful when visualizing complex geographic data, such as urban modeling or environmental simulations.
Space-Time Cube: A data projection that represents data over time and space. This is used to analyze patterns and trends in data over time.
"In a map projection, coordinates, often expressed as latitude and longitude, of locations from the surface of the globe are transformed to coordinates on a plane."
"Projection is a necessary step in creating a two-dimensional map and is one of the essential elements of cartography."
"All projections of a sphere on a plane necessarily distort the surface in some way and to some extent."
"Different map projections exist in order to preserve some properties of the sphere-like body at the expense of other properties."
"The study of map projections is primarily about the characterization of their distortions."
"There is no limit to the number of possible map projections."
"Projections are considered in several fields of pure mathematics, including differential geometry, projective geometry, and manifolds."
"Rather, any mathematical function that transforms coordinates from the curved surface distinctly and smoothly to the plane is a projection."
"The Earth and other large celestial bodies are generally better modeled as oblate spheroids."
"The surfaces of planetary bodies can be mapped even if they are too irregular to be modeled well with a sphere or ellipsoid."
"The most well-known map projection is the Mercator projection."
"This map projection has the property of being conformal."
"However, it has been criticized throughout the 20th century for enlarging regions further from the equator."
"Equal-area projections such as the Sinusoidal projection and the Gall–Peters projection show the correct sizes of countries relative to each other."
"The National Geographic Society and most atlases favor map projections that compromise between area and angular distortion."
"such as the Robinson projection"
"the Winkel tripel projection."
"Therefore, more generally, a map projection is any method of flattening a continuous curved surface onto a plane."
"Few projections in practical use are perspective."