1PLMAP(3plplot) PLplot API PLMAP(3plplot)
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6 plmap - Plot continental outline or shapefile data in world coordinates
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9 plmap(mapform, name, minx, maxx, miny, maxy)
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12 Plots continental outlines or shapefile data in world coordinates. A
13 demonstration of how to use this function to create different projec‐
14 tions can be found in examples/c/x19c. PLplot is provided with basic
15 coastal outlines and USA state borders. These can be used irrespective
16 of whether Shapefile support is built into PLplot. With Shapefile sup‐
17 port this function can also be used with user Shapefiles, in which case
18 it will plot the entire contents of a Shapefile joining each point of
19 each Shapefile element with a line. Shapefiles have become a popular
20 standard for geographical data and data in this format can be easily
21 found from a number of online sources. Shapefile data is actually pro‐
22 vided as three or more files with the same filename, but different
23 extensions. The .shp and .shx files are required for plotting Shapefile
24 data with PLplot.
25 Redacted form: plmap(mapform, name, minx, maxx, miny, maxy)
27 This function is used in example 19.
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31 mapform (PLMAPFORM_callback(3plplot), input)
32 A user supplied function to transform the original map data
33 coordinates to a new coordinate system. The PLplot-supplied map
34 data is provided as latitudes and longitudes; other Shapefile
35 data may be provided in other coordinate systems as can be found
36 in their .prj plain text files. For example, by using this
37 transform we can change from a longitude, latitude coordinate to
38 a polar stereographic projection. Initially, x[0]..[n-1] are the
39 original x coordinates (longitudes for the PLplot-supplied data)
40 and y[0]..y[n-1] are the corresponding y coordinates (latitudes
41 for the PLplot supplied data). After the call to mapform(), x[]
42 and y[] should be replaced by the corresponding plot coordi‐
43 nates. If no transform is desired, mapform can be replaced by
44 NULL.
45 name (PLCHAR_VECTOR(3plplot), input)
47 An ascii character string specifying the type of map plotted.
48 This is either one of the PLplot built-in maps or the file name
49 of a set of Shapefile files without the file extensions. For the
50 PLplot built-in maps the possible values are: "globe" -- conti‐
51 nental outlines "usa" -- USA and state boundaries "cglobe" --
52 continental outlines and countries "usaglobe" -- USA, state
53 boundaries and continental outlines
54 minx (PLFLT(3plplot), input)
57 The minimum x value of map elements to be drawn. For the built
58 in maps this is a measure of longitude. For Shapefiles the units
59 must match the projection. The value of minx must be less than
60 the value of maxx. Specifying a useful limit for these limits
61 provides a useful optimization for complex or detailed maps.
62 maxx (PLFLT(3plplot), input)
64 The maximum x value of map elements to be drawn
65 miny (PLFLT(3plplot), input)
67 The minimum y value of map elements to be drawn. For the built
68 in maps this is a measure of latitude. For Shapefiles the units
69 must match the projection. The value of miny must be less than
70 the value of maxy.
71 maxy (PLFLT(3plplot), input)
73 The maximum y value of map elements to be drawn.
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77 Many developers (who are credited at http://plplot.source‐
78 forge.net/credits.php) have contributed to PLplot over its long his‐
79 tory.
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82 PLplot documentation at http://plplot.sourceforge.net/documenta‐
83 tion.php.
84 August, 2017 PLMAP(3plplot)