raster-streamlines

Convert a vectorial raster field into streamlines. The output is in a convenient GeoJSON format compatible with d3js mapping.

INSTALL

To use with npm, just type

npm install raster-streamlines

To create the streamlines, a vectorial field is needed:

var srteamlines = require("raster-streamlines");
var properties = srteamlines.streamlines(u, v, geotransform, density, flip);

u is the speed in the x coordinates, where positive numbers go from right to left, as in the wind conventions
v is the speed in the x coordinates, where positive numbers go from lower to upper, as in the wind conventions
u and v must have the same dimensions, obviously
geotransform is a six elements array, as defined in the gdal library. It's an optional parameter, the array position coordinates are used if the array is not given
density is an optional parameter that changes the number of streamlines. When is 1 (default), the number is aprox. 60. If lower than 1, the lines will be fewer
flip is an optional parameter to change the v speed direction if set to true

When using directly in HTML, use the rastertools as the namespace

rastertools.streamlines(u, v, geotransform, flip);

See this block for a real world usage.