Set layer definition on Webmap through URL?

[RobertWinterbottom]

My question is that is it possible to set a layer definition on a Webmap through the URL? 

What I am essentially trying to do is I am building an app that has a profile page with a link to an AGOL webmap.  When the user clicks the link I would not only like to be able to take them to a webmap but also set a layer definition on the layer in the webmap. Each profile page is for a specific district and there are tons of districts over the whole country, can I link them to the webmap and pass in a definition expression, say something like 'DistrictId = 240042' and have that set on the map on load.

[JohnGravois]

have you seen Sonia's code sample in this forum post?  it allows her to fire a spatial query by appending X and Y coordinates to the Url of her app.  perhaps you could modify it to use similar information to create a definition query on your layer.

[RobertWinterbottom]

Thanks for the response, How would I get access to the layer though to apply the layer definition?  If it were for the map in my app I think this would be very easy but because it is a webmap on an AGOL account I don't have access to the layer(atleast not that I know of).  I am just giving my user an <a> tag with the link to the webmap to open it in a new page.  I was hoping to be able to have it open with a particular definition set on it.

[JohnGravois · Accepted solution]

you can definitely dig into the layers in the web map in an application written with our API.  this sample loops through the webmap layers to add them to a legend.

it sounds however like you are currently sharing a link to open the original web map (perhaps in the standard arcgis.com viewer?).  in order to build out the functionality you describe you would need to be linking to a configurable web application (that loads a web map based on its id) and similarly pulls additional information out of the Url to write a definition query on the fly.

[RobertWinterbottom]

you can definitely dig into the layers in the web map in an application written with our API.  this sample loops through the webmap layers to add them to a legend.

Thanks I have done this a few times, the API makes it pretty simple.

it sounds however like you are currently sharing a link to open the original web map (perhaps in the standard arcgis.com viewer?).  in order to build out the functionality you describe you would need to be linking to a configurable web application (that loads a web map based on its id) and similarly pulls additional information out of the Url to write a definition query on the fly.

But this is exactly what I was going for.  The webmap is currently living on the standard viewer.  I think my project manager would prefer I do this through the standard AGOL viewer but it sounds like at this time that is not possible. I will suggest this as an alternative to her as this would be fairly simple to build and see if it's something we can do.  Thanks a lot, I appreciate the response.

[JohnGravois]

no problem at all.  i see people share links to open web maps directly in the arcgis.com viewer quite a bit.  my perception is that it adds quite a bit of unnecessary background noise for a lot of end users. 

a clean, simple web mapping application is a much better way to present the web map.  and if it adds some logic to build a definition query on the fly, all the better 🙂