Weather map motion. Two-dimensional streamlines based on wind speeds at various levels show areas of convergence and divergence in the wind field, which are helpful in determining the location of features within the wind pattern. A popular type of surface weather map is the surface weather analysis, which plots isobars to depict areas of high pressure and low pressure. Cloud codes are translated into symbols and plotted on these maps along with other meteorological data that are included in synoptic reports sent by professionally trained observers. The use of weather charts in a modern sense began in the middle portion of the
Equal pay for equal work effects, with trade unions sometimes promoting conservatism. However, following the Second World War, trade unions and the legislatures of industrialized countries gradually embraced the principle of equal pay for equal work; one example of this process is the UK's introduction of the Equal Pay Act 1970 in response both to the Treaty of Rome and the Ford sewing machinists strike of 1968. In recent years European trade unions have generally exerted pressure on states and employers for progress in this direction. In international human rights law, the statement on equal pay is the 1951 Equal Remuneration Convention, Convention 100 of