How can you extract bands from a geotiff?

[john-a-m]

I noticed when browsing through the issues that issue #67 seems to imply that it is possible to visualize a band by providing a pixelValuesToColorFn which sounds good to me. Is there an example of how to leverage pixelValuesToColorFn to do this?

[DanielJDufour]

Sure thing. Here's a few examples:

• https://github.com/GeoTIFF/georaster-layer-for-leaflet-example/blob/master/examples/ndvi.html
• https://github.com/GeoTIFF/georaster-layer-for-leaflet-example/blob/master/examples/population.html
• https://github.com/GeoTIFF/georaster-layer-for-leaflet-example/blob/master/examples/identifying-wildfires-with-landsat.html

Let me know if you have any more questions!

[john-a-m]

If anyone comes across this what is important to know is that if a geotiff has bands then pixelValuesToColorFn will be given an array of values rather than a singular value. The population example highlights this well.

var layer = new GeoRasterLayer({
    attribution: "European Commission: Global Human Settlement",
    georaster: georaster,
    opacity: 0.75,
    resolution: 64,
    pixelValuesToColorFn: function (values) {
      var population = values[0];
      if (population === -200) return;
      if (population < 0) return;
      return scale(population).hex();
    }
});