eddy-geek

Terrain Analysis 3D Bug — Root Cause & Fix

Summary

The terrain-analysis layer type (from @eslopemap/maplibre-gl@5.21.2) fails to render in 3D terrain mode when many non-DEM layers (GeoJSON tracks, circles, symbols, etc.) are positioned between the hillshade layer and the terrain-analysis layer in the MapLibre style layer stack.

Root cause: Layer position in the style stack. When terrain-analysis layers are appended to the end of the layer stack via map.addLayer() (the default behavior), and 20+ other layers exist above the hillshade, 3D terrain rendering silently drops the terrain-analysis output. This appears to be a bug in the fork's render-to-texture pipeline for 3D terrain.

Fix applied: Move terrain-analysis layers into the initial style definition, immediately after the hillshade layer, instead of adding them dynamically via addLayer() during map.on('load').

eddy-geek

VsCode (home)

[
{ "key": "shift shift",      "command": "workbench.action.quickOpen" },

// default ctrl+k ctrl+s
{ "key": "alt+left",         "command": "workbench.action.navigateBack" },
// default ctrl+shift+-
{ "key": "alt+right",        "command": "workbench.action.navigateForward" },

eddy-geek

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eddy-geek

      slope: [
        'step', ['slope'],
        "#ffffff", // white
        20, "#c0ffff", // light sky blue
        24, "#57ffff", // bright cyan
        28, "#00d3db", // aqua blue
        31, "#fffa32", // sunshine yellow
        34, "#ffc256", // macaroni
        37, "#fd7100", // orange
        40, "#ff0000", // cherry red

eddy-geek

What this does

full interactive slope/aspect debug viewer using only maplibre-gl-js with:

• Hybrid DEM pipeline

  • Uses internal backfilled DEM tiles when available
  • Falls back to custom border-fixed tiles when needed
  • Status counters show internal vs fallback usage

• Terrain analysis overlay

eddy-geek

How to convert terrarrium terrain RGB mbtiles back into tif ?

You can do it with GDAL in two steps:

1. pick the correct decoder (Terrarium vs Mapbox Terrain‑RGB),
2. apply the formula to the RGB PNG tiles inside the MBTiles and write out a Float32 GeoTIFF (then optionally reproject to WGS84).

Below I give ready‑to‑run commands for both encodings, plus tips to choose the zoom level, mask with the alpha band, and reproject.

eddy-geek

#!/bin/bash

set -e  # Exit on any error

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

eddy-geek

#!/bin/sh
hda-verb /dev/snd/hwC0D0 0x20 0x500 0x0
hda-verb /dev/snd/hwC0D0 0x20 0x500 0x0
hda-verb /dev/snd/hwC0D0 0x20 0x500 0x99
hda-verb /dev/snd/hwC0D0 0x20 0x500 0x99
hda-verb /dev/snd/hwC0D0 0x20 0x500 0x99
hda-verb /dev/snd/hwC0D0 0x20 0x480 0x0
hda-verb /dev/snd/hwC0D0 0x20 0x500 0x99
hda-verb /dev/snd/hwC0D0 0x20 0x480 0x0
hda-verb /dev/snd/hwC0D0 0x20 0x500 0x99

eddy-geek

KDE Bug 466373 – Qt apps don't use wp-fractional-scale-v1 for hidpi fractional scaling on Wayland

SUMMARY Qt client apps using system Qt 5.15.8 still use the old downscaling mechanism to deal with fractional scaling, instead of wp-fractional-scale-v1, leading to visual artefacts.

STEPS TO REPRODUCE

1. Set "Scale" to fractional eg 135% in Display Configuration
2. Open a Qt app

OBSERVED RESULT

eddy-geek

def get_jpg_quality(pim: 'PIL.Image.Image') -> int:
    """
    Implement quality computation following ImageMagick heuristic algorithm:
    https://github.com/ImageMagick/ImageMagick/blob/7.1.0-57/coders/jpeg.c#L782
    Usage:
    ```
    pim = Img.open(...)
    quality = get_jpg_quality(pim)
    ```
    See also https://stackoverflow.com/questions/4354543/