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Mount Beerwah

Earlier today I posted a model of Mount Beerwah, and I had a request to do the same for Mount Barney, a couple of hundred kilometres to the south, in the Scenic Rim near the border between Queensland and New South Wales.

Barney has lots of secondary peaks and ridges, and to make it all load I made the easting and northing grid 25 × 25 metres, even though Geoscience Australia has elevation data to 5 metres. The grid nodes are coloured based on a couple of screenshots from Google Maps. The highest peak is at 1359 metres above sea level; the highest point in the data is at 1357.9 metres.

Manipulating the plot will cause Chrome on my Galaxy S3 to crash – there are about 300,000 triangles in the surface (309 × 240 grid nodes), and perhaps that's too many. Please let me know (email dw.barry@gmail.com or tweet @pappubahry) if you get a crash on a different device. Still it looks great on my laptop.

The x- and y-axes are UTM easting and northing; click/tap somewhere on the surface to see the co-ordinates below the plot.

Mouse controls: Left-click and drag to rotate; alt (Mac)- or ctrl (Windows)-click-drag or middle-click-drag to pan; scroll or shift-click-drag to zoom. Touch screen controls: one finger to rotate; two-finger scroll to pan; pinch to zoom. Click/tap on the cube icons to snap to a side-on view.

Imagery ©2016 DigitalGlobe, CNES / Astrium.

Clicked point: x =  ; y =  ; z =  .

You can see how the plot is constructed in the HTML source. The hard part is the data collection, particularly going from the Google Maps screenshot to the grid nodes. The Beerwah example has a download link with full details on doing these colour interpolations; the Barney example was trickier because the much larger area meant that the ASCII file from Geoscience Australia had too many columns for LibreOffice Calc, so I counted columns and did transposes in perl for a while.

Posted 2016-12-22.


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