leaflet-geotiff

A LeafletJS plugin for displaying geoTIFF raster data. Data can drawn as colored rasters or directon arrows. The layer can be clipped using a polygon.

DEMO

Instructions

1. Include the JavaScript file and dependencies

    <script src="https://unpkg.com/[email protected]/dist/leaflet.js"></script>
    <script src="https://unpkg.com/[email protected]/dist/main.js"></script>
    <script src="https://unpkg.com/[email protected]/src/plotty.js"></script>
    <script src="leaflet-geotiff.js"></script>
    <!-- Load any renderer you need -->
    <script src="leaflet-geotiff-plotty.js"></script>
    <script src="leaflet-geotiff-vector.js"></script>

2. Add a geoTIFF layer

// Create map
var layer = L.leafletGeotiff(url, options).addTo(map);

Parameters:

• url - GeoTIFF file URL. Currently only EPSG:4326 files are supported.
• options:
  • bounds - (optional) An array specifying the corners of the data, e.g. [[40.712216, -74.22655], [40.773941, -74.12544]]. If omitted the image bounds will be read from the geoTIFF file.
  • band - (optional, default = 0) geoTIFF band to read.
  • image - (optional, default = 0) geoTIFF image to read.
  • clip - (optional, default = undefined) Clipping polygon, provided as an array of [lat,lon] coordinates. Note that this is the Leaflet [lat,lon] convention, not geoJSON [lon,lat].
  • renderer - Renderer to use (see below).

Extended parameters for use with L.LeafletGeotiff.rgb() renderer:

• rBand - band index to use as R-band
• gBand - band index to use as G-band
• bBand - band index to use as B-band
• alphaBand - band index to use as alpha-band - NOTE: this can also be used in combination with transpValue, then referring to a color band specifying a fixed value to be interpreted as transparent
• transpValue - for all values equal to transpValue in the band alphaBand, the newly created alpha channel will be set to 0 (transparent), all other pixel values (except NaN values) will result in alpha 255 (opaque)

Renderer

Raster data rendered using Plotty: L.LeafletGeotiff.plotty(options) Options:

• displayMin - (optional, default = 0) Minimum values to plot.
• displayMax - (optional, default = 1) Maximum values to plot.
• clampLow, clampHigh - (optional, default = true) If true values outside displayMin to displayMax will be rendered as if they were valid values.
• colorScale - (optional, default = "viridis"). Plotty color scale used to render the image.

New color scales can be created using plotty's addColorScale method.

Vector data rendered as arrows: L.LeafletGeotiff.vectorArrows(options) Options:

• arrowSize - (optional, default = 20) Size in pixels of direction arrows for vector data.

Advanced usage options

1. Data values can be extracted using the getValueAtLatLng(lat,lng) method.
2. Custom renderer can be implemented by extending L.LeafletGeotiffRenderer.

Dependencies

• Leaflet >= 0.7.7
• geotiff.js
• plotty (optional)