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    Method mapline

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    mapline(MapFunc, String, Double, Double, Double, Double, Int32[])

    plmapline: Plot all or a subset of Shapefile data using lines in world coordinates

    Declaration
    public void mapline(MapFunc mapform, string name, Double minx, Double maxx, Double miny, Double maxy, Int32[] plotentries)
    Parameters
    Type Name Description
    MapFunc mapform

    A user supplied function to transform the coordinates given in the shapefile into a plot coordinate system. By using this transform, we can change from a longitude, latitude coordinate to a polar stereographic project, for example. Initially, x[0]..[n-1] are the longitudes and y[0]..y[n-1] are the corresponding latitudes. After the call to mapform(), x[] and y[] should be replaced by the corresponding plot coordinates. If no transform is desired, mapform can be replaced by NULL.

    System.String name

    An ascii character string specifying the file name of a set of Shapefile files without the file extension.

    Double minx

    The minimum x value to be plotted. This must be in the same units as used by the Shapefile. You could use a very large negative number to plot everything, but you can improve performance by limiting the area drawn. The units must match those of the Shapefile projection, which may be for example longitude or distance. The value of minx must be less than the value of maxx.

    Double maxx

    The maximum x value to be plotted. You could use a very large number to plot everything, but you can improve performance by limiting the area drawn.

    Double miny

    The minimum y value to be plotted. This must be in the same units as used by the Shapefile. You could use a very large negative number to plot everything, but you can improve performance by limiting the area drawn. The units must match those of the Shapefile projection, which may be for example latitude or distance. The value of miny must be less than the value of maxy.

    Double maxy

    The maximum y value to be plotted. You could use a very large number to plot everything, but you can improve performance by limiting the area drawn.

    Int32[] plotentries

    A vector containing the zero-based indices of the Shapefile elements which will be drawn. Setting plotentries to NULL will plot all elements of the Shapefile.

    Remarks

    Plot all or a subset of Shapefile data using lines in world coordinates. Our 19th standard example demonstrates how to use this function. This function plots data from a Shapefile using lines as in plmap, however it also has the option of also only drawing specified elements from the Shapefile. The vector of indices of the required elements are passed as a function argument. The Shapefile data should include a metadata file (extension.dbf) listing all items within the Shapefile. This file can be opened by most popular spreadsheet programs and can be used to decide which indices to pass to this function.

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