13.6. Little Planet

13.6.1. 概観

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. フィルターの呼び出し方

This filter is found in the image window menu under FiltersMapLittle Planet….

13.6.3. オプション

図17.288 Little Planet filter options

Little Planet filter options

オプション

Presets, Preview, Split view
[注記] 注記

These options are described in 「Common Features」.

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 補間アルゴリズム

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

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.

図17.289 Original Images

Original Images

Original panorama

Original Images

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.

図17.290 Results

Results

Prepared image

Results

Filter applied