https://community.esri.com/people/EPolle_TensingInternational/blog/2020/03/24/arcgis-javascript-with-uk-data-table-of-content
Basemapgallery
In the first exercise in this series we just had a single basemap in our map. Here we are going to add a BasemapGallery allowing users to switch basemaps.
Please note: all basemaps added to the gallery need to have the same spatial reference. And because our first basemap is projected in British National Grid, all the other ones should have this same spatial reference.
We have found these basemaps which meet this requirement:
In the code below we use the Basemap class to create six basemap objects. Next we combine these objects in a single LocalBasemapsSource, which in turn we add to the BasemapGallery widget.
Follow this link to see the end result of this exercise:
ArcGIS JavaScript with UK data - OS Basemapgallery
<SPAN class="doctype token"><!DOCTYPE html></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>html</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>head</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>meta</SPAN> <SPAN class="attr-name token">charset</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>utf-8<SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>meta</SPAN> <SPAN class="attr-name token">name</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>viewport<SPAN class="punctuation token">"</SPAN></SPAN> <SPAN class="attr-name token">content</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>initial-scale<SPAN class="punctuation token">=</SPAN>1, maximum-scale<SPAN class="punctuation token">=</SPAN>1, user-scalable<SPAN class="punctuation token">=</SPAN>no<SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>title</SPAN><SPAN class="punctuation token">></SPAN></SPAN>ArcGIS JavaScript with UK data - OS Basemapgallery<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>title</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>link</SPAN> <SPAN class="attr-name token">rel</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>stylesheet<SPAN class="punctuation token">"</SPAN></SPAN> <SPAN class="attr-name token">href</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>https://js.arcgis.com/4.15/esri/css/main.css<SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="language-javascript script token"><SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>script</SPAN> <SPAN class="attr-name token">src</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>https://js.arcgis.com/4.15/<SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN><SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>script</SPAN><SPAN class="punctuation token">></SPAN></SPAN></SPAN>
<SPAN class="language-css style token"><SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>style</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="selector token">html, body, #viewDiv</SPAN> <SPAN class="punctuation token">{</SPAN>
<SPAN class="property token">padding</SPAN><SPAN class="punctuation token">:</SPAN> 0<SPAN class="punctuation token">;</SPAN>
<SPAN class="property token">margin</SPAN><SPAN class="punctuation token">:</SPAN> 0<SPAN class="punctuation token">;</SPAN>
<SPAN class="property token">height</SPAN><SPAN class="punctuation token">:</SPAN> 100%<SPAN class="punctuation token">;</SPAN>
<SPAN class="property token">width</SPAN><SPAN class="punctuation token">:</SPAN> 100%<SPAN class="punctuation token">;</SPAN>
<SPAN class="punctuation token">}</SPAN>
<SPAN class="selector token">.esri-basemap-gallery__item-thumbnail</SPAN> <SPAN class="punctuation token">{</SPAN>
<SPAN class="property token">width</SPAN><SPAN class="punctuation token">:</SPAN> auto<SPAN class="punctuation token">;</SPAN>
<SPAN class="punctuation token">}</SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>style</SPAN><SPAN class="punctuation token">></SPAN></SPAN></SPAN>
<SPAN class="language-javascript script token"><SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>script</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token function">require</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">[</SPAN>
<SPAN class="string token">"esri/Map"</SPAN><SPAN class="punctuation token">,</SPAN>
<SPAN class="string token">"esri/geometry/Point"</SPAN><SPAN class="punctuation token">,</SPAN>
<SPAN class="string token">"esri/views/MapView"</SPAN><SPAN class="punctuation token">,</SPAN>
<SPAN class="string token">"esri/Basemap"</SPAN><SPAN class="punctuation token">,</SPAN>
<SPAN class="string token">"esri/widgets/BasemapGallery"</SPAN><SPAN class="punctuation token">,</SPAN>
<SPAN class="string token">"esri/widgets/BasemapGallery/support/LocalBasemapsSource"</SPAN>
<SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">function</SPAN><SPAN class="punctuation token">(</SPAN>Map<SPAN class="punctuation token">,</SPAN> Point<SPAN class="punctuation token">,</SPAN> MapView<SPAN class="punctuation token">,</SPAN> Basemap<SPAN class="punctuation token">,</SPAN> BasemapGallery<SPAN class="punctuation token">,</SPAN> LocalBasemapsSource<SPAN class="punctuation token">)</SPAN> <SPAN class="punctuation token">{</SPAN>
<SPAN class="comment token">// Basemaps Esri UK</SPAN>
<SPAN class="keyword token">let</SPAN> OS_Open_Background_Esri_UK <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Basemap</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>portalItem<SPAN class="punctuation token">:</SPAN> <SPAN class="punctuation token">{</SPAN>id<SPAN class="punctuation token">:</SPAN> <SPAN class="string token">"a4ee9f2805754f4b9004103f67688bf1"</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN> <SPAN class="comment token">//OS Open Background</SPAN>
<SPAN class="keyword token">let</SPAN> OS_Open_Gray_Esri_UK <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Basemap</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>portalItem<SPAN class="punctuation token">:</SPAN> <SPAN class="punctuation token">{</SPAN>id<SPAN class="punctuation token">:</SPAN> <SPAN class="string token">"93320e50f3f3419795946b1243aadb1e"</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN> <SPAN class="comment token">//OS Open Grey</SPAN>
<SPAN class="keyword token">let</SPAN> OS_Open_Gray_Labels_Esri_UK <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Basemap</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>portalItem<SPAN class="punctuation token">:</SPAN> <SPAN class="punctuation token">{</SPAN>id<SPAN class="punctuation token">:</SPAN> <SPAN class="string token">"7be6d1f81ab047fda02107a97079ccd3"</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN> <SPAN class="comment token">//OS Open Grey Labels</SPAN>
<SPAN class="keyword token">let</SPAN> OS_Open_Carto_Esri_UK <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Basemap</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>portalItem<SPAN class="punctuation token">:</SPAN> <SPAN class="punctuation token">{</SPAN>id<SPAN class="punctuation token">:</SPAN> <SPAN class="string token">"0bd3a4a6fd674a90a7d0a9e5f36fb59b"</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN> <SPAN class="comment token">//OS Open Carto</SPAN>
<SPAN class="keyword token">let</SPAN> OS_Open_Raster_Esri_UK <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Basemap</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>portalItem<SPAN class="punctuation token">:</SPAN> <SPAN class="punctuation token">{</SPAN>id<SPAN class="punctuation token">:</SPAN> <SPAN class="string token">"5b5ff94ca7414a26b75e0d337a023d38"</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN> <SPAN class="comment token">//OS Open Rasters</SPAN>
<SPAN class="keyword token">let</SPAN> GB_Dark_Grey_Esri_UK <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Basemap</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>portalItem<SPAN class="punctuation token">:</SPAN> <SPAN class="punctuation token">{</SPAN>id<SPAN class="punctuation token">:</SPAN> <SPAN class="string token">"a118075240bc4e4f8062265ecdad0e7e"</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN> <SPAN class="comment token">//GB Dark Grey</SPAN>
<SPAN class="keyword token">let</SPAN> UKBasemaps <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">LocalBasemapsSource</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>
basemaps <SPAN class="punctuation token">:</SPAN> <SPAN class="punctuation token">[</SPAN>OS_Open_Background_Esri_UK<SPAN class="punctuation token">,</SPAN> OS_Open_Carto_Esri_UK<SPAN class="punctuation token">,</SPAN> OS_Open_Gray_Esri_UK<SPAN class="punctuation token">,</SPAN> OS_Open_Gray_Labels_Esri_UK<SPAN class="punctuation token">,</SPAN> OS_Open_Raster_Esri_UK<SPAN class="punctuation token">,</SPAN> GB_Dark_Grey_Esri_UK<SPAN class="punctuation token">]</SPAN>
<SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
<SPAN class="keyword token">let</SPAN> map <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Map</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>
basemap<SPAN class="punctuation token">:</SPAN> OS_Open_Carto_Esri_UK
<SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
<SPAN class="keyword token">let</SPAN> view <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">MapView</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>
spatialReference<SPAN class="punctuation token">:</SPAN> <SPAN class="number token">27700</SPAN><SPAN class="punctuation token">,</SPAN>
container<SPAN class="punctuation token">:</SPAN> <SPAN class="string token">"viewDiv"</SPAN><SPAN class="punctuation token">,</SPAN>
map<SPAN class="punctuation token">:</SPAN> map<SPAN class="punctuation token">,</SPAN>
center<SPAN class="punctuation token">:</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Point</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>x<SPAN class="punctuation token">:</SPAN> <SPAN class="number token">500000</SPAN><SPAN class="punctuation token">,</SPAN> y<SPAN class="punctuation token">:</SPAN> <SPAN class="number token">500000</SPAN><SPAN class="punctuation token">,</SPAN> spatialReference<SPAN class="punctuation token">:</SPAN> <SPAN class="number token">27700</SPAN><SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">,</SPAN>
zoom<SPAN class="punctuation token">:</SPAN> <SPAN class="number token">7</SPAN>
<SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
<SPAN class="keyword token">let</SPAN> basemapGallery <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">BasemapGallery</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>
view<SPAN class="punctuation token">:</SPAN> view<SPAN class="punctuation token">,</SPAN>
source<SPAN class="punctuation token">:</SPAN> UKBasemaps
<SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
view<SPAN class="punctuation token">.</SPAN>ui<SPAN class="punctuation token">.</SPAN><SPAN class="token function">add</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">[</SPAN>basemapGallery<SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"top-right"</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
<SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>script</SPAN><SPAN class="punctuation token">></SPAN></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>head</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>body</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>div</SPAN> <SPAN class="attr-name token">id</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>viewDiv<SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN><SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>div</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>body</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>html</SPAN><SPAN class="punctuation token">></SPAN></SPAN><SPAN class="line-numbers-rows"><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN></SPAN>
