Civil Rights
Movements, leaders, victories and the continuing fight for equality.
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THE BHP WIRE —
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Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
Innovation, patents, science, technology and world-changing contributions.
Pioneers, champions, Negro Leagues, records, activism and excellence.
Meet the people whose lives, choices and achievements shaped the journey.
Black towns, communities, institutions and places where history happened.
Moments that changed communities, movements, institutions and the nation.
Katherine Johnson’s mathematical calculations helped guide some of America’s most important early space missions while she confronted the racial and gender barriers faced by Black women in twentieth-century America.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
The National Spatial Reference System (NSRS), managed by the National Geodetic Survey (NGS), is a coordinate system that includes latitude, longitude, elevation, and other values. The NSRS consists of a National Shoreline, the NOAA CORS Network[3] (a system of Global Positioning System Continuously Operating Reference Stations), a network of permanently marked points, and a set of models that describe dynamic geophysical processes affecting spatial measurements. The system is based on the datums NAD 83 and NAVD 88.[4]
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The North American-Pacific Geopotential Datum of 2022 (NAPGD2022) is a geodetic datum set produced by the U.S. National Geodetic Survey to improve the National Spatial Reference System (NSRS).[5][6][7] It will replace the North American Datum of 1983 (NAD 83) and the North American Vertical Datum of 1988 (NAVD 88) with a new geometric reference frame and geopotential datum.[8] In association with this release, a new, time-dependent geoid model, GEOID2022, will also be released.[9] The release date for these models was planned for 2022 but they have been delayed.
Attribution: contains public domain material copied from ngs.noaa.gov
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The National Spatial Reference System (NSRS), managed by the National Geodetic Survey (NGS), is a coordinate system that includes latitude, longitude, elevation, and other values. The NSRS consists of a National Shoreline, the NOAA CORS Network (a system of Global Positioning System Continuously Operating Reference Stations), a network of permanently marked points, and a set of models that describe dynamic geophysical processes affecting spatial measurements. The system is based on the datums NAD 83 and NAVD 88. The North American-Pacific Geopotential Datum of 2022 (NAPGD2022) is a geodetic datum set produced by the U.S. National Geodetic Survey to improve the National Spatial Reference System (NSRS). It will replace the North American Datum of 1983 (NAD 83) and the North American Vertical Datum of 1988 (NAVD 88) with a new geometric reference frame and geopotential datum. In association with this release, a new, time-dependent geoid model, GEOID2022, will also be released. The release date for these models was planned for 2022 but they have been delayed.
A geodetic control network is a network, often of triangles, that are measured precisely by techniques of control surveying, such as terrestrial surveying or satellite geodesy. It is also known as a geodetic network, reference network, control point network, or simply control network. A geodetic control network consists of geodetic markers, which are stable, identifiable points or vertices with published coordinate values derived from observations that tie the points together. In the U.S., there is a national control network called the National Spatial Reference System (NSRS). Many organizations may contribute information to the geodetic control network. In the United Kingdom, the Ordnance Survey maintains the OS Net network. The higher-order (high precision, usually millimeter-to-decimeter on a scale of continents) control points are normally defined in both space and time using global or space techniques, and are used for "lower-order" points to be tied into. The lower-order control points are normally used for engineering, construction and navigation. The scientific discipline that deals with the establishing of coordinates of points in a control network is called geodesy.
A projected coordinate system – also called a projected coordinate reference system, planar coordinate system, or grid reference system – is a type of spatial reference system that represents locations on Earth using Cartesian coordinates (x, y) on a planar surface created by a particular map projection. Each projected coordinate system, such as "Universal Transverse Mercator WGS 84 Zone 26N," is defined by a choice of map projection (with specific parameters), a choice of geodetic datum to bind the coordinate system to real locations on the earth, an origin point, and a choice of unit of measure. Hundreds of projected coordinate systems have been specified for various purposes in various regions. When the first standardized coordinate systems were created during the 20th century, such as the Universal Transverse Mercator, State Plane Coordinate System, and British National Grid, they were commonly called grid systems; the term is still common in some domains such as the military that encode coordinates as alphanumeric grid references. However, the term projected coordinate system has recently become predominant to clearly differentiate it from other types of spatial reference system. The term is used in international standards such as the EPSG and ISO 19111 (also published by the Open Geospatial Consortium as Abstract Specification 2), and in most geographic information system software.
A spatial reference system (SRS) or coordinate reference system (CRS) is a framework used to precisely measure locations on, or relative to, the surface of Earth as coordinates. It is thus the application of the abstract mathematics of coordinate systems and analytic geometry to geographic space. A particular SRS specification (for example, "Universal Transverse Mercator WGS 84 Zone 16N") comprises a choice of Earth ellipsoid, horizontal datum, map projection (except in the geographic coordinate system), origin point, and unit of measure. Thousands of coordinate systems have been specified for use around the world or in specific regions and for various purposes, necessitating transformations between different SRS. Although they date to the Hellenistic period, spatial reference systems are now a crucial basis for the sciences and technologies of Geoinformatics, including cartography, geographic information systems, surveying, remote sensing, and civil engineering. This has led to their standardization in international specifications such as the EPSG codes and ISO 19111:2019 Geographic information—Spatial referencing by coordinates, prepared by ISO/TC 211, also published by the Open Geospatial Consortium as Abstract Specification, Topic 2: Spatial referencing by coordinate. The above refers to locations directly on the surface of the earth. Information on elevation may also be specified, via a vertical reference frame, so-called vertical CRS, or an integrated 3D CRS. Terminology in this area is evolving in line with increasing technical sophistication in measurement.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Brown v. Board of Education in 1954.
