topic Re: Retrieving legend symbol info from a service that has no legend in ArcGIS JavaScript Maps SDK Questions

Retrieving legend symbol info from a service that has no legend

BrettGreenfield__DNR_ — Wed, 19 Feb 2014 17:49:11 GMT

I'm working on developing a custom legend for a webmap of ours by using esri.request to retrieve JSON information about the legend symbol and dynamically creating it for each of the layers in my map. This works fine for our services: I sent the request to http://<mapservice>/legend, and I get the appropriate response.

However, this particular map is also using a few services from an external source, and when I visit the URL for those services, there's no link to "legend", and if I manually add "/legend" to the end of the service URL, I get an error saying Invalid URL. The URL to one of the services in question is here: http://mdewin25.mde.state.md.us/ArcGIS/rest/services/Maryland_Shellfish_Closure_Areas/MapServer.

Is there a way to retrieve the legend symbol information from this service? I'm concerned I'm going to have to just take screen shots of the legend symbols, save them as images, and add those to the map...I really don't want to have to do that.

Re: Retrieving legend symbol info from a service that has no legend

KenBuja — Wed, 19 Feb 2014 18:35:43 GMT

I don't think you have that option on this service. It was created in 9.3.1 (click on the Home link to see this) and it looks like the Legend resource capability was only added in 10.0, SP 1. Take a look at the What's New page for the Rest API

Re: Retrieving legend symbol info from a service that has no legend

BrettGreenfield__DNR_ — Wed, 19 Feb 2014 18:38:32 GMT

Thanks Ken. I'd read that and figured that was the issue. My next question then, how does the legend dijit request the legend information from services hosted on older versions of ArcServer? If I use the legend dijit everything shows up fine, so there's a successful request being made somewhere.

Re: Retrieving legend symbol info from a service that has no legend

BrettGreenfield__DNR_ — Wed, 19 Feb 2014 18:45:38 GMT

Okay, looks like I figured it out. I watched the requests made as I loaded a page that used the legend dijit via Firebug and found I can make the request to the service if I add "http://utility.arcgis.com/sharing/tools/legend?soapUrl=" before the URL to the actual service. Tested it and this seems to work.

Re: Retrieving legend symbol info from a service that has no legend

KenBuja — Wed, 19 Feb 2014 18:59:53 GMT

Glad to hear you found a solution. You should mark your post as the answer.

Re: Retrieving legend symbol info from a service that has no legend

Anonymous User — Sat, 11 Dec 2021 20:58:38 GMT

Hi :)...hoping you could complete your thought on retrieving the legend symbol from the server, this is the closest answer I've found in the threads so far! When using esri/request to get legend info in json, how do you then use the url to get the actual image off the server?

var legendImageRequest = esriRequest({
 url : "https://www.server.com/arcgis2/rest/services/test/test/MapServer/legend",
 content : {f : "json"},
 handleAs : "json",
});
legendImageRequest.then(function(response) {
 console.log(response.layers[0].legend[0]);
});

Thanks!

Re: Retrieving legend symbol info from a service that has no legend

Anonymous User — Thu, 26 Jun 2014 23:07:23 GMT

Got it, sorry, needed to add 'images' to the api call with the image url: "https://www.server.com/arcgis2/rest/services/test/test/MapServer/0/images/8674387q2"