PLMAPLINE(3plplot)

💖 PLMAPLINE 💖

ok so bestie, we're in the PLplot API today, and the star of the show is plmapline from section 3plplot — she plots Shapefile data as lines in world coordinates and honestly? iconic. 🎀

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✨ NAME ✨

plmapline — plot all or a subset of Shapefile data using lines in world coordinates. that's it, that's the vibe. 🦋

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🌸 SYNOPSIS 🌸

plmapline(mapform, name, minx, maxx, miny, maxy, plotentries,
nplotentries)

like, seven arguments plus a count, she's a little extra but she delivers 💅

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⭐ DESCRIPTION ⭐

okay so real talk: plmapline plots all or a subset of Shapefile data using lines in world coordinates. Our 19th standard example literally demonstrates how to use this function, so if you wanna see her in action, go look at that 👑

She plots data from a Shapefile using lines, same energy as plmap(3plplot) — but with a glow-up: she also has the option of only drawing specified elements from the Shapefile. You pass the vector of indices of the required elements as a function argument. periodt. 💫

Now, 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 you can use it to decide which indices to pass to this function. so you can literally open it, look at your lil rows, and pick your faves 🌈

Redacted form: plmapline(mapform, name, minx, maxx, miny, maxy, plotentries)

This function is used in example 19. yes, again. she's committed.

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💜 ARGUMENTS 💜

• mapform (PLMAPFORM_callback(3plplot), input) — 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. no thoughts, just NULL 🫶
• name (PLCHAR_VECTOR(3plplot), input) — an ascii character string specifying the file name of a set of Shapefile files without the file extension. yes, just the name, bestie, she'll figure out the rest 💅
• minx (PLFLT(3plplot), input) — 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. like, that's not a suggestion, that's the rules 🔥
• maxx (PLFLT(3plplot), input) — 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. lowkey the performance tip is free real estate ✨
• miny (PLFLT(3plplot), input) — 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. same energy, y edition 🦋
• maxy (PLFLT(3plplot), input) — 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. mmhm you know the drill 💖
• plotentries (PLINT_VECTOR(3plplot), input) — 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. zero-based, so start counting at 0, not 1, i'm begging 🙈
• nplotentries (PLINT(3plplot), input) — the number of items in plotentries. Ignored if plotentries is NULL. she said "not needed, next" 💀

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👑 AUTHORS 👑

Many developers (who are credited at http://plplot.sourceforge.net/credits.php) have contributed to PLplot over its long history. shoutout the whole group chat, fr fr 🫶

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🌟 SEE ALSO 🌟

PLplot documentation at http://plplot.sourceforge.net/documentation.php. go read it, it's giving study session 📚

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and that's the page, bestie 💅 this was PLMAPLINE(3plplot) from the PLplot API, dated August, 2026 — mwah, drink some water, and go plot something gorgeous 🌸💖