Experiments with "arrow" display

[Ben Wyss]

The Geodetic Strain data includes information about the strain movement, this information needs to be rendered.

Strain Direction

exx describes the magnitude of the strain in the pure east-west direction (east being positive, west being negative). eyy describes the magnitude of the strain in the north-south direction (north being positive).
exy doesn't really have a geographical meaning.

[Ben Wyss (bmwyss)]

I have had an initial success with rendering the strain direction and magnitude of movement in QGIS. Unfortunately the style used for this layer is complicated, and because of this it has become difficult to move the style of the layer into a web mapping tool like Geoserver or Tilemill.
I have tried to use some QGIs plugins like: export layer to tilemill, QTiles, and Quantumnik.
Export layer to tilemill can not be used with QGIS 'new symbologyology'.
Qtiles seems to only work with an older version of QGIs 1.9.0 master.
Quantumnik is unmaintained, the layer drop down not populating: https://github.com/yuletide/QGISTileMillExport/issues/1

One possible solution could be to create a QGIs server and server the layer to the web this way. Another option could be to allow users to view the layer off line within QGIS.

The conclusion is to determine in greater detail the requirement of this visualization. And in the mean time wait for the QGIS 2.0 release and see if we can then find another solution.

[Ben Wyss (bmwyss)]

I was able to convert the x y vertex into a angle and intensity that could be used in tilemill. I will produce two proof of concepts one with a normal intensity and one with a log base 10 intensity.