ccg-r2d

A Java library for rendering 2D Euclidean spatial data using ccg-v2d for vector (point, line, polygon) data and ccg-grids for raster data.

Visualising geometry helps develop ccg-v2d. The work in 2D is helping develop 3D geometry libraries: ccg-v3d and ccg-r3d. Some example static renderings of data are shown below.

GSHHS low resolution land/sea polygons, 825 x 2000:

Triangle rotations, colours and circumcircles

Three rotated overlapping large triangles (one colour for the triangle and a different colour for each respective edge):

Multiple small rotated triangles some overlapping with their circumcircle outlines drawn in white (one colour for all triangles and a different colour for each respective edge:

Triangle rotated 48 times with increasing angle (the last triangle draw has just one colour for it's edge):

Triangle rotated a bit, then the result rotated a bit - 48 times (the last triangle has just one colour for it's edge):

With grids

A triangle on a couple of randomly coloured grids (one grid underlies the other, the top grid is located in the upper right of the image):

Triangle intersections

Two rotated triangles with a two triangle intersection:

Two rotated triangles with a four triangle intersection:

Polygon

Polygon with a polygon internal hole. The external edge of the polygon is coloured red and the edge of the hole is coloured blue:

GSHHS land polygons

The geography data come in five resolutions:

1. full resolution: Original (full) data resolution.
2. high resolution: About 80 % reduction in size and quality.
3. intermediate resolution: Another ~80 % reduction.
4. low resolution: Another ~80 % reduction.
5. crude resolution: Another ~80 % reduction.

Global

Crude resolution

Heirarchy ignored revealing the convex hulls with darker shade for edges:

Without some of antarctica revealing holes:

165 x 400:

660 x 1600:

825 x 2000:

Great Britain

Crude resolution

45 x 42:

90 x 84:

150 x 140:

Low resolution

150 x 140:

Isle of Man

Intermediate resolution

160 x 212

Full resolution

160 x 212

Dependencies

• Java SE 21
• Mainly ccg-v2d for vectors and ccg-grids for rasters. Both of thesehave few light weight dependencies.
• Please see the POM for details.

Development plans/ideas

• Calculate and show some example polygon-polygon intersections.
• Create some animations with geometries moving relative to others.
• Generate some more example renderings of geographical data:
  • Global Self-Consistent Hierarchical High-Resolution Shoreline (GSHHS) data
    • GSHHG-GMT
  • Surface elevation
  • Land cover
  • Temperature
  • Rainfall
  • National boundaries and human population
• Make a versioned release on Maven Central.
• Investigate ways to speed up rendering.
• Community development:
  • Raise awareness
  • Develop use cases
  • Reach out to developers of (GMT, Apache SIS, JTS).

Contributing

• Thanks for thinking about this.
• For a collaborative project, there should be a Code of Conduct and Contributor Guide based on something like this: Open Source Guide
• Meanwhile if you want instructions or there is an issue, please report this in the usual way :)

LICENCE

• APACHE LICENSE, VERSION 2.0
• Other licences are possible!

Acknowledgements and thanks

• The University of Leeds has indirectly supported this work by employing me over the years and encouraging me to develop the skills necessary to produce this library.
• Thank you Eric for the BigMath library.