Empty graphic in Jupyter

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Empty graphic in Jupyter

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#1 by (3 votes)

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I am replicating this code to plot a line and a point but when I try to visualize the graphic it is empty.

%matplotlib inline

from matplotlib import pyplot
from shapely.geometry import LineString, Point, LinearRing

# Datos de entrada
Line =  [(-58.39323087479187, -34.64522852285068), (-58.39493519860744, -34.64593911202303), (-58.39540370387294, -34.64612018963881), (-58.39577715270643, -34.64624297063709), (-58.3961720086682, -34.64636735300267), (-58.39657393244798, -34.64649079664271), (-58.39686900560828, -34.64658786576401), (-58.39768408267521, -34.64688376919202), (-58.39804117638568, -34.64699057960223), (-58.39811749931905, -34.64700849164973), (-58.39828903137601, -34.64704378391358), (-58.39848415993365, -34.64708122410398), (-58.3986547387477, -34.64709449060737), (-58.3988514934597, -34.64709955836587), (-58.39897325079004, -34.6471023653607), (-58.39913887311855, -34.64708744614302), (-58.40078230339798, -34.64694668280777), (-58.4011366548087, -34.64692373544752), (-58.40140137506319, -34.64690660901691), (-58.40169294994597, -34.64689298223946), (-58.40188791399491, -34.64691373562576), (-58.40216794959328, -34.64695369573664), (-58.41441599275006, -34.64898345419851), (-58.41468645364731, -34.64902341675737), (-58.41491789917437, -34.6490522244158), (-58.41504783372419, -34.64906712767555), (-58.41517069354625, -34.64908171429391), (-58.41533660567228, -34.64909137548982), (-58.41610344894117, -34.64910924442286), (-58.41663883920926, -34.64911070715178), (-58.41691994816962, -34.64910623905278), (-58.41712925394172, -34.64908282123896), (-58.41735140092969, -34.64905175937751), (-58.4175040105956, -34.64901464682342), (-58.41778163827102, -34.64893890857992), (-58.41810776345819, -34.64882463807892), (-58.42014859446244, -34.64801074189261), (-58.42109129459963, -34.64768468167974), (-58.42150738131538, -34.64755870865789), (-58.42342555778116, -34.64704856595483), (-58.42380036444368, -34.64696522849173), (-58.42402399498763, -34.64692538456899), (-58.42422994553617, -34.64689682578112), (-58.42442882836995, -34.64688048716456), (-58.42466544132492, -34.64686749516407), (-58.42492895224804, -34.64686969903472), (-58.42519118859626, -34.64689581060387), (-58.42548633816839, -34.64693076251233), (-58.42574834123136, -34.64696690278817), (-58.42600734692162, -34.64703299983701), (-58.42633487929256, -34.64713342399471), (-58.42672363380665, -34.6472903832091), (-58.42701863504796, -34.64744017525714), (-58.42735477118806, -34.64764714102999), (-58.42758954729708, -34.64780944247776), (-58.42780426987807, -34.64798874926387), (-58.42805931284784, -34.64825160891823), (-58.42826384085686, -34.64851328718624), (-58.42836837245316, -34.64865441916345), (-58.42849097552769, -34.64886100909527), (-58.42863862000018, -34.64921981114054), (-58.43039902344795, -34.65411150588781), (-58.43058099211167, -34.65454759092934), (-58.43074440690579, -34.65487960245804), (-58.43091147516467, -34.65519055733962), (-58.43112803380347, -34.65554914847827), (-58.43260609566938, -34.65801519415205), (-58.43278567440816, -34.65827265019357), (-58.43296016110701, -34.65845540315134), (-58.43315011877778, -34.65865061801186), (-58.43335842356506, -34.65885169235345), (-58.43349821535271, -34.65894935913921), (-58.43369231539262, -34.65907745659961), (-58.43391244522258, -34.65921105679707), (-58.4342196854351, -34.65939138210857), (-58.43446159367213, -34.65950262175289), (-58.4354319679709, -34.65989668701516), (-58.44002778106239, -34.66183363815986), (-58.44218397209216, -34.66275027310008), (-58.46163757545956, -34.67090968101208), (-58.46246050330255, -34.67120817614321), (-58.46280547898094, -34.67132107658005), (-58.46307488578911, -34.67139608443851), (-58.46332241010779, -34.67144991252323), (-58.46353300409209, -34.67149541798045), (-58.46859653017688, -34.67249959570204), (-58.46908781436287, -34.67259411624501), (-58.46938034898276, -34.67267684368898), (-58.46981999535013, -34.67282189408634), (-58.47017709131737, -34.67296547046871), (-58.47422872212128, -34.67473003403723), (-58.47458907678709, -34.67490463353656), (-58.47485536868304, -34.67507001487545), (-58.47511721636123, -34.67527809815956), (-58.47561611823835, -34.67573966172805), (-58.47637678148585, -34.67650147966764), (-58.4772898411353, -34.677473083393), (-58.47756878106423, -34.67779366716631), (-58.47927838887487, -34.68008637250686), (-58.4796189824651, -34.68046368453628), (-58.4797836819284, -34.68061589623475), (-58.47997298162954, -34.68077149644261), (-58.48013854950542, -34.68087214089938), (-58.48033951807771, -34.68099482470753), (-58.48077178430249, -34.68117907983302), (-58.4809809942354, -34.68125468946911), (-58.48151812211091, -34.68141121492266), (-58.49074865351113, -34.68364996209967), (-58.49280644305118, -34.68416717487745), (-58.49323181266317, -34.68430677581161), (-58.4939040130434, -34.68450404480966), (-58.494446444632, -34.68469758388901), (-58.50679022633284, -34.68987115611775), (-58.50863040256832, -34.6906581855909), (-58.51021336002367, -34.69130911057548), (-58.51092048468821, -34.69162906732615), (-58.51128148474532, -34.69180116103016), (-58.51164513166684, -34.69197626961216), (-58.51190552938787, -34.6921423269721), (-58.51223224913973, -34.6923465503359), (-58.51266317587315, -34.69263696928233), (-58.51283797439013, -34.69275574911642), (-58.51343928772994, -34.69323891435921), (-58.51613617076313, -34.69565149779803), (-58.51639524277449, -34.6959621229764), (-58.51657880735801, -34.69623621532357), (-58.51668736518741, -34.69648714304233), (-58.51677990482248, -34.69677220564932), (-58.51681912473175, -34.69694815217243), (-58.51683540541565, -34.69728978685934), (-58.51682586767205, -34.69757721116119), (-58.51679226699013, -34.697818097686), (-58.51670205772855, -34.69812198637412), (-58.51657448656194, -34.69837726193614), (-58.51643210417134, -34.69861385564264), (-58.51621815101113, -34.69887195886386), (-58.5160233966457, -34.69905049204797), (-58.51546229204164, -34.69948099921363), (-58.51164101129704, -34.70237114559549)]
Punto = (-58.45,-34.68)

# Computar la proyección del punto sobre la línea
line = LineString(Line)
p = Point(Punto)
np = line.interpolate(line.project(p))

# Función para pintar una serie de puntos en el color que se le pase como parámetro
def plot_coords(ax, ob, color='#999999'):
    x, y = ob.xy
    ax.plot(x, y, 'o', color=color, zorder=1)

# Función para pintar una línea (irá superpuesta a los puntos)
def plot_line(ax, ob, color='#6699cc'):
    x, y = ob.xy
    ax.plot(x, y, color=color, alpha=0.7, linewidth=3, solid_capstyle='round', zorder=2)

# Creación de la figura con matplotlib
fig = pyplot.figure(1, figsize=(6,6), dpi=90)
ax = fig.add_subplot(111)

# Pintar la línea y los puntos que la componen
plot_line(ax, line)
plot_coords(ax, line)

# Pintar en rojo el punto externo y en verde su proyección
plot_coords(ax, p, "red")
plot_coords(ax, np, "green")
ax.set_aspect(1)

Image of the graphic

python python-3.x jupyter

asked by Sebastian 20.03.2018 в 15:38

source

1 answer

JQuery code to pure JS It is safe to save a jwt token in LocalStorage

score 3 · Accepted Answer

The code is perfectly valid and when I run it on my Notebook the correct graph appears.

After private conversations with the user, it is finally discovered that the cause of the problem was the way in which the previous code had been copied and pasted into the Jupyter Notebook.

I have decided to leave a record of the solution in case someone else falls into this same error.

The problem was that the user had separated into two different cells the code that creates the figure:

# Creación de la figura con matplotlib
fig = pyplot.figure(1, figsize=(6,6), dpi=90)
ax = fig.add_subplot(111)

of the code that paints the lines and points in it:

# Pintar la línea y los puntos que la componen
plot_line(ax, line)
plot_coords(ax, line)

# Pintar en rojo el punto externo y en verde su proyección
plot_coords(ax, p, "red")
plot_coords(ax, np, "green")
ax.set_aspect(1)

By separating the execution into two cells, you can effectively see the same result as the user. After the first cell, the empty graph appears and the next one does not appear anymore.

This is due to the way in which matplotlib operates within Notebook when the backend inline is active. In that case, at the end of the cell in which the figure has been created, that figure is overturned and the global variable plt associated with it is discarded. Therefore we turn the figure when it is still "half done".

The problem was solved by bringing these two cells together in one.