|
| 1 | +library(leaflet) |
| 2 | + |
| 3 | +#' h1. Leaflet now with Proj4Leaflet support. |
| 4 | + |
| 5 | +#' This is very very hackish for now.<br/> |
| 6 | +#' <P>But as HTMLWidget's factory/initialize method has no way to pass params, |
| 7 | +#' and the CRS can only be specified at Map creation time (even in 1.0), the only |
| 8 | +#' way to support Proj4Leaflet is by destroying the default map and creating a new one. |
| 9 | +#' I haven't thought all the details here. But this is the first hack at it. |
| 10 | +#' A lot of stuff in the onRender can be moved to R, I just wanted something quick and dirty. |
| 11 | +#' </P><br/><br/>Thoughts/Comments ?<br/><br/> |
| 12 | + |
| 13 | +#' The code is adaptation of [this](https://github.com/turban/Leaflet.Graticule/blob/master/examples/mollweide.html) sans the graticule part.<br/><br/> |
| 14 | +extJS <- htmltools::htmlDependency("countries", "1.0.0", |
| 15 | + src = c(href = "https://cdn.rawgit.com/turban/Leaflet.Graticule/master/examples/lib/"), |
| 16 | + script = "countries-110m.js" |
| 17 | +) |
| 18 | + |
| 19 | +addExtJS <- function(map) { |
| 20 | + map$dependencies <- c(map$dependencies, list(extJS)) |
| 21 | + map |
| 22 | +} |
| 23 | + |
| 24 | +leaflet() %>% addTiles() %>% |
| 25 | + addProj4Leaflet() %>% # Add Proj4Leaflet plugin JSes. |
| 26 | + addExtJS() %>% # Load external GeoJson File |
| 27 | + htmlwidgets::onRender(" |
| 28 | + function(el, x) { |
| 29 | +
|
| 30 | + // remove the original map |
| 31 | + var oldMap = this; |
| 32 | + oldMap.remove(); |
| 33 | +
|
| 34 | + // Sphere Mollweide: http://spatialreference.org/ref/esri/53009/ |
| 35 | + var crs = new L.Proj.CRS('ESRI:53009', |
| 36 | + '+proj=moll +lon_0=0 +x_0=0 +y_0=0 +a=6371000 +b=6371000 +units=m +no_defs', |
| 37 | + { |
| 38 | + resolutions: [65536, 32768, 16384, 8192, 4096, 2048] |
| 39 | + } |
| 40 | + ); |
| 41 | +
|
| 42 | + // create a new map in place of old map using new CRS |
| 43 | + var newMap = L.map(el.id, { |
| 44 | + crs: crs, |
| 45 | + maxZoom: 5 |
| 46 | + }); |
| 47 | +
|
| 48 | + L.geoJson(countries, { |
| 49 | + style: { |
| 50 | + color: '#000', |
| 51 | + weight: 0.5, |
| 52 | + opacity: 1, |
| 53 | + fillColor: '#fff', |
| 54 | + fillOpacity: 1 |
| 55 | + } |
| 56 | + }).addTo(newMap); |
| 57 | + newMap.fitWorld(); |
| 58 | +
|
| 59 | + //debugger; |
| 60 | + } |
| 61 | + ") |
| 62 | + |
| 63 | +leaflet() %>% addTiles() %>% |
| 64 | + addProj4Leaflet() %>% # Add Proj4Leaflet plugin JSes. |
| 65 | + addExtJS() %>% # Load external GeoJson File |
| 66 | + # Graticule not strictly necessary just aesthetics |
| 67 | + addGraticule(style= |
| 68 | + list( color= '#777', |
| 69 | + weight= 1, opacity= 0.5)) %>% |
| 70 | + htmlwidgets::onRender(" |
| 71 | + function(el, x) { |
| 72 | +
|
| 73 | + // remove the original map |
| 74 | + var oldMap = this; |
| 75 | + oldMap.remove(); |
| 76 | +
|
| 77 | + // Sphere Mollweide: http://spatialreference.org/ref/esri/53009/ |
| 78 | + var crs = new L.Proj.CRS('ESRI:53009', |
| 79 | + '+proj=moll +lon_0=0 +x_0=0 +y_0=0 +a=6371000 +b=6371000 +units=m +no_defs', |
| 80 | + { |
| 81 | + resolutions: [65536, 32768, 16384, 8192, 4096, 2048] |
| 82 | + } |
| 83 | + ); |
| 84 | +
|
| 85 | + // create a new map in place of old map using new CRS |
| 86 | + var newMap = L.map(el.id, { |
| 87 | + crs: crs, |
| 88 | + maxZoom: 5 |
| 89 | + }); |
| 90 | +
|
| 91 | + L.graticule({ |
| 92 | + sphere: true, |
| 93 | + style: { |
| 94 | + color: '#777', |
| 95 | + opacity: 1, |
| 96 | + fillColor: '#ccf', |
| 97 | + fillOpacity: 1, |
| 98 | + weight: 2 |
| 99 | + } |
| 100 | + }).addTo(newMap); |
| 101 | +
|
| 102 | +
|
| 103 | + L.graticule({ |
| 104 | + style: { |
| 105 | + color: '#777', |
| 106 | + weight: 1, |
| 107 | + opacity: 0.5 |
| 108 | + } |
| 109 | + }).addTo(newMap); |
| 110 | +
|
| 111 | +
|
| 112 | + L.geoJson(countries, { |
| 113 | + style: { |
| 114 | + color: '#000', |
| 115 | + weight: 0.5, |
| 116 | + opacity: 1, |
| 117 | + fillColor: '#fff', |
| 118 | + fillOpacity: 1 |
| 119 | + } |
| 120 | + }).addTo(newMap); |
| 121 | + newMap.fitWorld(); |
| 122 | +
|
| 123 | + //debugger; |
| 124 | + } |
| 125 | + ") |
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