[GIS] Changing basemaps with different spatial references (ArcGIS Javascript)

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I've got a new requirement to switch basemaps that have different spatial references. The app is using ArcGIS Javascript, and switching to Silverlight is not an option at this point in development. I saw this question from 2 years ago and was hoping there was an alternative. Is there an easier way to change basemaps that have different spatial references in 3.6?

Best Answer

The basemap defines the spatial reference of the map; changing the basemap and its spatial reference could cause unintended issues. Some possible alternatives are:

Destroy and recreate the map with the new basemap and load any other layers. You would want to be sure you destroy all handlers and other objects before recreating the map to avoid memory leaks.
Create a new map with the new basemap. If you want to switch back and forth, keep the old map; otherwise destroy it.
Insert the new basemap as a layer just above the basemap in the display order. The new layer would be warped to the map's spatial reference, which might slow down your map and look kinda crappy depending on the layer's contents.

Related Solutions

[GIS] How To Use Tiled Map Services with Different Spatial References in ArcGIS API for JavaScript

Tiled map services added to a JS API map have to match the map's spatial reference. The map's spatial reference is set when you create the map if you specify an extent or it's set to the spatial reference of the first layer added to the map.

If you need to use tiled map services that are in different spatial references, then yes, you'll have to destroy and create a new map when you change tiled map services. Ideally, your tiled map services would all use the same spatial reference but it sounds like you might not have control over that.

[GIS] Map Application Requires Refresh to Initialize

I would consolidate all of those dojo.addOnLoad() calls. I suspect something isn't getting loaded before a function is getting called.

Strip all dojo.addOnLoad calls from all of your external javascript files and bundle them into one call in your main HTML file. Put all the functions you want to fire on load into a new function at the bottom of your javascript like this:

function init() {
  basemapToggle();
  layerToggle();
  whatEver();
}
dojo.addOnLoad(init);

This will ensure that everything has loaded before trying to fire off any functions.

Best Answer

Related Solutions

[GIS] How To Use Tiled Map Services with Different Spatial References in ArcGIS API for JavaScript

[GIS] Map Application Requires Refresh to Initialize

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