Islands

The islands of Flat Holm and Steep Holm. Inspired by Hamish Haswell-Smith.
QGIS
Published

May 20, 2022

Flat Holm and Steep Holm

Flat Holm and Steep Holm are islands in the Bristol Channel visible from Weston-Super-Mare. I spent many happy holidays in Weston-Super-Mare staying with my grandparents.

The maps are inspired by the style of Hamish Haswell-Smith in his Scottish Islands book.

Flat Holm.

Flat Holm.

Steep Holm.

Steep Holm.

Contains OS data © Crown Copyright and database right 2022.

Also contains OpenStreetMap data © OpenStreetMap Contributors, 2022.

Data

Tools I used

  • QGIS

What did I learn?

  • How to add a grid in a way which makes it possible to put it under the island.
  • Using symbol levels to display the polygon height layers in correct order in QGIS.

Process

  • Converted contour and waterline layers from OS OpenZoomstack to polygons - Lines to polygons
  • Had to add height field to waterline polygons and add 0 as height. Note, this should be double, not integer data type.
  • Merged all polygon height layers
  • Set categorised styling on height.
  • Use Symbol levels to get displaying in right order, with 0 at bottom and highest height at top.
  • Colour as wished…
  • Use Create grid tool to create a grid which can be placed under the island. Note this doesn’t have grid coordinates, though Haswell-Smith’s maps don’t have coordinates either.

What would I like to change or add?

  • Can I find names for some of the sea areas? e.g. bays?
  • Grid coordinates for the grid? Annotations? Labels?
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