Plot DEM

Category: Mega-Polis → Visualisation → Visualisation Design Tools
Node ID: SvMegapolisPlotDem
Tooltip: Plot a Dem Array
Dependencies: richdem (uses rd.rdShow) :contentReferenceoaicite:0

Functionality

Plots a DEM (2D raster/array) using RichDEM’s rd.rdShow(...).

When run is enabled, the node visualises the input Dem Array with:

  • optional axes on/off
  • configurable figure size (width/height)
  • selectable sequential colormap
  • ignore_colours=[0] (treats value 0 as a special colour to ignore) :contentReferenceoaicite:1

Inputs

Socket Type Description
Dem Array SvStringsSocket 2D DEM array to plot. Must be linked. :contentReferenceoaicite:2

Parameters

Name Type Default Description
run Bool False If True, triggers rd.rdShow(...) to display the plot. :contentReferenceoaicite:3
axes Bool False Show/hide plot axes. :contentReferenceoaicite:4
width Int 8 Plot width used in figsize=(width, height). :contentReferenceoaicite:5
height Int 5 Plot height used in figsize=(width, height). :contentReferenceoaicite:6
colour Enum inferno Sequential colormap passed as cmap=self.colour. :contentReferenceoaicite:7

Available colormaps (enum)

Includes (as defined in the node):
viridis, plasma, inferno, magma, cividis, Greys, Purples, Blues, Greens, Oranges, Reds, YlOrBr, YlOrRd, OrRd, PuRd, RdPu, BuPu, GnBu, PuBu, YlGnBu, PuBuGn, BuGn, YlGn, binary, gist_yarg, gist_gray, gray, bone, pink, spring, summer, autumn, winter, cool, Wistia, hot, afmhot, gist_heat, copper. :contentReferenceoaicite:8

Outputs

This node has no output sockets. It is a visualisation-only node that displays a plot when run=True. :contentReferenceoaicite:9

Example

Plot a DEM array

  1. Connect a DEM array (e.g., from Read DEM or a terrain attribute output) to Dem Array.
  2. Set:
    • run = True
    • axes = False
    • width = 10, height = 6
    • colour = inferno (or any other colormap)
  3. The node will display the DEM using:

rd.rdShow(dem_array, ignore_colours=[0], axes=axes, cmap=colour, figsize=(width, height)) :contentReferenceoaicite:10

Notes / gotchas

  • Plotting only happens when run is enabled; otherwise the node does nothing beyond reading the input. :contentReferenceoaicite:11
  • ignore_colours=[0] may hide/neutralise zero-valued pixels (often used for NoData masks in some DEM pipelines). :contentReferenceoaicite:12