Terrain RGB tiles can be quite large at low (z0-z10) zoom levels the blue channel of the terrainRGB represents around 25M of vertical accuracy, when viewing tiles where 1 pixel is 1,000m sub meter accurarcy is not required.
from initial test cases this can reude the tile size by 50%+
tile z_x_y
Before
After
Bytes saved
% reduction
03_7_4
3,607
2,737
-870
-24.12%
04_15_9
7,802
4,305
-3,497
-44.82%
05_31_19
23,031
8,872
-14,159
-61.48%
06_63_39
64,024
23,827
-40,197
-62.78%
07_126_79
110,251
45,738
-64,513
-58.51%
08_252_159
66,791
28,809
-37,982
-56.87%
09_505_319
125,658
64,711
-60,947
-48.50%
10_1010_639
143,054
91,446
-51,608
-36.08%
11_2020_1278
98,940
62,342
-36,598
-36.99%
12_4040_2556
29,740
29,740
0
0
Modification
Truncates the terrainRGB blue channel down to greatly reduce the file size of the output tiles.
Motivation
Terrain RGB tiles can be quite large at low (z0-z10) zoom levels the blue channel of the terrainRGB represents around 25M of vertical accuracy, when viewing tiles where 1 pixel is 1,000m sub meter accurarcy is not required.
from initial test cases this can reude the tile size by 50%+
Modification
Truncates the terrainRGB blue channel down to greatly reduce the file size of the output tiles.
Checklist
If not applicable, provide explanation of why.