# Graphics overlay doesn't work properly

**URL:** <https://community.wolfram.com/t/graphics-overlay-doesnt-work-properly/22983>\
**Category:** Questions\
**Tags:** graphics-and-visualization, interface-construction\
**Created:** [October 18, 2023, 8:28pm UTC](https://community.wolfram.com/t/graphics-overlay-doesnt-work-properly/22983 "2023-10-18T20:28:41Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![joeltenenbaum](https://avatars.discourse-cdn.com/v4/letter/j/eada6e/32.png) [@joeltenenbaum](https://community.wolfram.com/u/joeltenenbaum)\
**Post date:** [October 18, 2023, 8:28pm UTC](https://community.wolfram.com/t/graphics-overlay-doesnt-work-properly/22983/1 "2023-10-18T20:28:41Z")

</div>

I have two Graphics images, the first generated by Manipulate and the second generated directly that don’t overlap correctly. Changing both primary graphs to Manipulate doesn’t solve the problem.  
Version that overlays properly (See attached notebook)

Version that doesn’t overlay properly (see attached notebook)

[Open in Wolfram Cloud ↗](https://www.wolframcloud.com/obj/361c64ae-809b-49b4-b9fd-2af5a46c07c8)

The underlying definitions

```
In[24] = lineLONCUR = Line[{{iloncapture2, 1}, {iloncapture2, 9}}]
In[25] = lineLONGRA = Show[Graphics[lineLONCUR]]
In[26]:= lineTRKCUR = Line[{{0.0, 1.6}, {1.7, 3.2}, {3.4, 4.2}, {5.1, 5.4}, {6.9, 6.2}, {8.6, 6.2}, {103, 6.1}}];
In[27]:= Line[{{0.`, 1.6`}, {1.7`, 3.2`}, {3.4`, 4.2`}, {5.1`, 5.4`}, {6.9`, 6.2`}, {8.6`, 6.2`}, {103, 6.1`}}];
In[28]:= Line[{{0.`, 1.6`}, {1.7`, 3.2`}, {3.4`, 4.2`}, {5.1`, 5.4`}, {6.9`, 6.2`}, {8.6`, 6.2`}, {103, 6.1`}}];
In[29]:= lineTRKGRA = Show[Graphics[{Green, Thick, lineTRKCUR}]]
In[30]:= lineTURCUR = Line[{{8.51, 5.85}, {8.71, 5.85}}];
In[31]:= lineTURGRA = Show[Graphics[{Red, Thick, lineTURCUR}]]

```

The one that overlays properly

```
Manipulate[
  wspdLEVshort2 = 
   Table[wspd3d[[klev, jlat, ilon]], {jlat, nlat, 1, -1}, {ilon, 1, nlon, 1}];
  klevcapture = klev;
  gLEV1 = 
   ListContourPlot[wspdLEVshort2, ContourLabels -> All, AxesLabel -> {Longitude, Latitude}, 
    Contours -> {90, 80, 70, 60, 50, 40} , PlotLabel -> "wspdLEV", PlotLegends -> Automatic]
  , {{klev, 3}, 1, 5, 1}
  ]
 ]

gLEV1comb = Show[gLEV1, lineLONGRA, lineTRKGRA, lineTURGRA]

```

The one that doesn’t overlay properly

```
gLEV2 = ListContourPlot[wlinLEV, ContourLabels -> All, 
  AxesLabel -> {Longitude, Latitude}, 
  Contours -> {90, 80, 70, 60, 50, 40} , PlotLabel -> "wspdLEV", 
  PlotRegion -> {{0.0, 1.0}, {0.0, 1.0}}, PlotLegends -> Automatic]

v2LEV2comb = Show[{lineLONGRA, lineTRKGRA, lineTURGRA, gLEV2}]

```

[correct\_and\_incorrect\_overlays.nb](https://community.wolfram.com/uploads/short-url/1cItKmEaqc0bvjQt8GpCgabQKxM.nb) (33.4 KB)

---

<div class="post-metadata">

**Author:** ![gianlucagorni](https://avatars.discourse-cdn.com/v4/letter/g/ec9cab/32.png) [@gianlucagorni](https://community.wolfram.com/u/gianlucagorni)\
**Post date:** [October 19, 2023, 7:37am UTC](https://community.wolfram.com/t/graphics-overlay-doesnt-work-properly/22983/2 "2023-10-19T07:37:03Z")

</div>

It appears to be a problem of `PlotRange`. When you `Show` more than one plot, the overlay will use the `PlotRange` of the first plot. Also, if gLEV2 is last, it will sit on top of the previous lines and make them invisible underneath. Place `gLEV2` first in the list:

```
Show[gLEV2,lineLONGRA, lineTRKGRA, lineTURGRA]

```

Otherwise, use `Epilog` within `ListContourPlot`.  
By the way, there is no need for `Show` when only one `Graphics` is inside: `Show[Graphics[lineLONCUR]]` is the same as `Graphics[lineLONCUR]`

---

<div class="post-metadata">

**Author:** ![joeltenenbaum](https://avatars.discourse-cdn.com/v4/letter/j/eada6e/32.png) [@joeltenenbaum](https://community.wolfram.com/u/joeltenenbaum)\
**Post date:** [October 20, 2023, 8:22pm UTC](https://community.wolfram.com/t/graphics-overlay-doesnt-work-properly/22983/3 "2023-10-20T20:22:51Z")

</div>

Thanks for the suggestions. Some background: the difference between gLEV1 and gLEV2 is to get the axis labels to be the meteorologically appropriate values, with fake negative pressures to get the correct vertical display of atmospheric pressure (-150 hPa at top) and Latitude (60N to 40N). The figure is a slice of wind speed through the jet stream.

When I put gLEV2 at the start, i.e. Show[{gLEV2, lineLONGRA, lineTRKGRA, lineTURGRA}] I get a blank display box but otherwise proper x and y axis labels and the color legends.

Which function, ListContourPlot or Show takes the PlotRange parameters? Am I understanding correctly that these should be -350 to -150 (negative pressure in hectoPascals) and -70 to 0 ( i.e. west Longitude)

Joel

---

<div class="post-metadata">

**Author:** ![gianlucagorni](https://avatars.discourse-cdn.com/v4/letter/g/ec9cab/32.png) [@gianlucagorni](https://community.wolfram.com/u/gianlucagorni)\
**Post date:** [October 21, 2023, 7:53am UTC](https://community.wolfram.com/t/graphics-overlay-doesnt-work-properly/22983/4 "2023-10-21T07:53:41Z")

</div>

It seems to me that you are feeding `ListContourPlot` a simple matrix of speed values. This way the frame labels will only note the position within the matrix. To get more meaningful frame labels you should give a list (not a matrix) of triples `{pressure, latitude, speed}` or whatever. Compare the labels:

```
ListContourPlot[Table[Sin[i + j^2], {i, -1, 2, 0.1},
  {j, 0, 3, 0.1}]]
ListContourPlot[Flatten[Table[{j, i, Sin[i + j^2]},
   {i, -1, 2, 0.1}, {j, 0, 3, 0.1}], 1]]

```

As for adding lines on top of the contour plot, I would recommend `Epilog`:

```
ListContourPlot[Table[Sin[i + j^2], {i, 0, 3, 0.1}, {j, 0, 3, 0.1}],
 Epilog -> {Line[{{-20, -20}, {20, 20}}]}]

```

---

<div class="post-metadata">

**Author:** ![joeltenenbaum](https://avatars.discourse-cdn.com/v4/letter/j/eada6e/32.png) [@joeltenenbaum](https://community.wolfram.com/u/joeltenenbaum)\
**Post date:** [October 26, 2023, 6:36pm UTC](https://community.wolfram.com/t/graphics-overlay-doesnt-work-properly/22983/5 "2023-10-26T18:36:21Z")

</div>

When I try emulating your suggestion (to use Flatten), I get an error message

```
In[67] = wspdLEVshort3 = Flatten[Table[wspd3d[[klev, jlat, ilon]], {jlat, nlat, 1, -1}, {ilon, 1, nlon, 1}], 1]
Out[67] = {13.7266, 15.414, 21.2157, 24.9529, 30.6142, 31.7384, 32.2047, \
33.6632, 38.2124, 51.1077, 40.0414, 18.06, 17.703, 18.7609, 24.5397, \
31.4082, 37.9464, 42.0565, 43.5092, 42.0817, 51.6718, 52.7562, \
39.4708, 17.4501, 21.3099, 21.0234, 28.2605, 39.5729, 48.4302, \
55.9663, 58.1384, 60.184, 59.1318, 39.6699, 35.4416, 17.9134, \
27.4215, 23.1979, 31.0662, 46.8974, 58.2954, 75.8074, 80.1236, \
71.3519, 50.4602, 40.5332, 42.4953, 15.0675, 33.2243, 27.041, 33.452, \
53.1378, 83.8582, 78.9329, 66.6444, 54.6909, 37.9928, 41.7945, \
47.9264, 11.802, 37.7803, 27.9041, 37.1021, 62.3661, 76.0097, \
60.4854, 47.1717, 33.8486, 36.0846, 43.461, 34.9605, 9.00443, \
41.0756, 31.5089, 41.1696, 70.1772, 62.726, 47.3514, 32.3545, \
33.3947, 42.8117, 48.8211, 23.8703, 14.382, 42.1381, 5031.67, \
44.8849, 66.148, 52.6835, 33.1125, 23.337, 35.1117, 49.8902, 41.995, \
18.2291, 14.5471, 40.3319, 32.73, 46.2485, 58.3091, 36.0893, 21.0668, \
28.6275, 47.8213, 47.8315, 21.2894, 15.0483, 20.5185}

ListContourPlot::arrayerr: {13.7266,15.414,21.2157,24.9529,30.6142,31.7384,32.2047,33.6632,38.2124,51.1077,<<98>>} 

```

must be a valid array.

The full printout is attached. Because of travel I’m only able to work on this slowly.

Joel

[test28B\_flatten\_page\_all.pdf](https://community.wolfram.com/uploads/short-url/5zPCz3XI9H0lIajJZqP3hstfdDp.pdf) (2.53 MB)

---

<div class="post-metadata">

**Author:** ![gianlucagorni](https://avatars.discourse-cdn.com/v4/letter/g/ec9cab/32.png) [@gianlucagorni](https://community.wolfram.com/u/gianlucagorni)\
**Post date:** [October 26, 2023, 7:11pm UTC](https://community.wolfram.com/t/graphics-overlay-doesnt-work-properly/22983/6 "2023-10-26T19:11:00Z")

</div>

You have probably flattened too much. You have to flatten only to level 1: `Flatten[matrix 1]`, so that you have a list of triples.