13.6. Little Planet
| 13. Filtres Mappage |

### 13.6. Little Planet

#### 13.6.1. Généralités

This filter converts a panorama into a small planet. All images don't fit this filter. The ideal image is a 360° x 180° image, also known as equirectangular image. We will see that it is possible to use normal images also.

#### 13.6.2. Ouverture du filtre

This filter is found in the image window menu under Filters → Map → Little Planet….

#### 13.6.3. Options

Figure 17.288. « Little Planet » filter options

Options

Presets, Preview, Split view

  | Note
  These options are described in Section 2, « Options communes ».

Pan

  Horizontal camera panning. If « Inverse transform » option is checked, the « pan » option moves line of sight horizontally. Else, it works as « Spin » option.

Tilt

  Vertical camera panning. Moves line of sight upwards/downwards.

Spin

  Spin angle around camera axis. Rotates planet around line of sight.

Zoom

  Zoom level. Zooms planet in/out.

Inverse transform

  Do the inverse mapping; useful for touching up zenith, nadir or other parts of panorama.

Resampling method

  Interpolation methods are described in Interpolation

  « Cubic » may give better result.

Use the selection as input/Use the entire layer as input

  If a selection exists, the filter will use it. Else, the entire layer will be used.

#### 13.6.4. Using Little Planet filter with an equirectangular image

| Astuce
You can find free equirectangular images at https://commons.wikimedia.org/wiki/Category:360°_panoramas_with_equirectangular_projection.

Ettling_Isar_panorama.jpg by © Simon Waldherr under CC by-sa 4.0

GIMP opened this 16000x8000 pixels original image in a 1000x500 px frame at zoom 6.25. This is a screenshot scaled to 600x300 px. Note the empty sky, the horizon perfectly horizontal, the vanishing perspective.

Filter applied

#### 13.6.5. Using Little Planet filter with a normal image

Your panorama rarely satisfies conditions necessary for this filter, especially if you cut it off a larger image. The Little Planet filter brings left and right image sides together, and creates an unwanted sharp limit if sides are different. An uneven horizon gives an irregular circle. A blue empty sky occupying the upper half of the image and a horizontal horizon are perfect. Usually, you will have to prepare your panorama before using filter.

Figure 17.289. Original Images

Original panorama

Filter applied directly with default options

1. Wipe sky: with Color Picker, darker blue to toolbox foreground and lighter blue to toolbox background. Rectangular selection of sky including a small part of horizon. In the selection, draw a Gradient from top to bottom.

2. Select the left border of the image.

3. Copy the selection and Paste it as New layer.

4. Q shortcut to open the Align tool.

5. Click on new layer (superimposed on selection area): new layer limits appear. Align new layer to image right side.

6. Select>None.

7. Flip new layer horizontally.

   New layer aligned to image right side and flipped: left and right image sides are now the same. Sky wiped out. Horizon horizontalized.

8. Add a black Layer Mask to new layer.

9. Apply a black-to-white gradient to layer mask.

10. Apply Little planet filter.

Figure 17.290. Results

Prepared image

Filter applied

13.5. Illusion |  | 13.7. Panorama Projection

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