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A way to access a layer inside a map service without accessing it as a feature layer?

dougbrowning

I want to access one layer of a map service to show it in a list. I do not want to add it as a layer using /MapServer/0 in config.xml because then I lose the dynamic display properties that the /MapServer provides. (The layer has 100,000 features so it blows up as a feature layer.)

Can I get at it in a Map Service or is there a way to add a just layer in config.xml that is dynamic display wise?

Have tried many things.

One was to publish a new map service each time but then there are so many map services the server bogs.

Second was to use setMaxAllowableOffset as in this post http://forums.arcgis.com/threads/49416-maxAllowableOffset-on-operationalLayers. But the ZOOM_END does not seem to be firing in 3.1. This blog post http://blogs.esri.com/esri/arcgis/2011/06/13/feature-layers-can-generalize-geometries-on-the-fly/ says that this concept is what ArcGIS Online does.

In the end all I want to do it be able to list layers multiple times, in multiple places, without having to create another Map Service all the time. In other words granular control over how and where layers (not whole maps) are listed while still keeping the dynamic display properties).

Concept: Kinda like ArcGIS Online where I am building a map up from multiple layers, each of which may be in a different map service.

Any ideas would be very appreciated, this has been struggled with for some time.

thanks

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Accepted answers

RobertScheitlin__GISP

Doug,

Have you looked at LayerDefinitions and/or visibleLayers on the ArcGISDynamicMapServiceLayer?

http://resources.arcgis.com/en/help/flex-api/apiref/com/esri/ags/layers/ArcGISDynamicMapServiceLayer.html

All comments

dougbrowning

Is there a way to use sublayers for this? So I can have the TOC display just one sublayer of a layer?

This would also allow a user to reorder the draw order of sublayers.

AntGiles

Doug,

I was wondering that myself but from what I have read I think sub layers are only used for creating different popup windows on each of your layers.

Have you tried feature layers with ondemand mode?

Regards

Anthony

dougbrowning

It looks like on demand mode just limits the features to the current extent. The problem is all of these are national layers and I am sure people will turn them on at the national (US) scale often. Zoomed in they are not that slow but full extent the browser can not even load all 100K features.

There must be a way because you can make just one layer of a map visible. I am going to look into how the checkbox makes just one layer of the map visible.

Benjamin Jones.jpg

RobertScheitlin__GISP

dougbrowning

Thanks this is really close. Is this available in AS? The mxml seems static.

I am thinking I would make the TOC just like in ArcMap. So I start with a empty TOC and Map (do not let the code load in the layers from the config.xml). Then when the user clicks on a layer name (which is a sublayer) I then tell the TOC/Map to add that sub layer.

In other words the user click tells TOC to go ahead and load sublayer 0 of map service X. (But do not load (or just not show) in the TOC say sublayer 1 of map service X)

AntGiles

Doug,

I know I directed you to ths widget before:

http://www.arcgis.com/home/item.html?id=4ed10ea387444952a3f3f501fee02b76

But did you have a look at it because this does something similar to what you are trying, it allows you to add / remove layers after the application has loaded (these can be individual feature layers from a map service if required).

Regards

Anthony

dougbrowning

Thanks a lot.

I looked at it briefly but I wanted a different UI. Then when i hit the just one layer of a map service issue I had looked at so much stuff I forgot about it.

Looks promising. But the issue I see is that it loads feature layers as /FeatureServer/0 but then they are not dynamically rendered like they are with /MapServer (at least if you say MapServer/0 they are not since they you have to say type feature not dynamic).

I need to show one layer (sublayer) out of a MapServer in the TOC. So tell it - in this Map Service just put this sublayer in the TOC. Some of our Map Service have 190+ layers and I just want one of those - and since it has 103K polygons it needs to be dynamic.

Maybe I can edit that in...

RobertScheitlin__GISP

Doug,

Sure anything you can do in MXML you can do in AS (as all MXML actually gets turned into AS when compiled). For the visibleLayers all you do is hand it a array of layer IDs that you want visible.

dougbrowning

Robert.   I then can change toc.categories to stop it from showing a tree nest structure right?

I am guessing it will still show
     Map Service name ->
             Group Name ->
                    Layer Name

RobertScheitlin__GISP

Doug,

That is correct, it will still show up in the TOC structure just unchecked. Currently there is no way to just add one layer of a map service as type dynamic and not have all the rest of the layers show up in the TOC.

dougbrowning

Someone before me was able to do that - looks like they used this.

toc.hideTopLevelItems = hideTopLevelItems;

public function set hideTopLevelItems( value:Boolean ):void
{
   _hideTopLevelItems = value;

   // Propagate this property to child TOC components
   for each (var toc:TOC in _childTocs)
   {
    toc.hideTopLevelItems = _hideTopLevelItems;
   }
}

RhettZufelt

Doug,

That is correct, it will still show up in the TOC structure just unchecked. Currently there is no way to just add one layer of a map service as type dynamic and not have all the rest of the layers show up in the TOC.

Am I missing something here:

Seems that in the TOCWidget.xml

<excludelayer mapservice="RCC WasteSites">0,2</excludelayer>

with 3 layers in my dynamic map service will only display layer id=1 in the TOC (and only draws that layer)?

Also, Doug,

I have seen some that have done similar and thier approach was to put all layers in the exclude list, then programatically remove the layers they want to see. Depending on the amount of "work" it needs to do, might be easier than manipulating the visibleLayers array.

R_

RobertScheitlin__GISP

Rhett,

I guess the only thing you missed is that Doug is not talking about the TOCWidget.

dougbrowning

Rhett. This is exactly what I did at first and it worked great in my samples. But when I started on the real one I found that I could only exclude whole map services.

Robert is correct I am talking about the MapSwitcherWidget. But I am not tied to it. Where is this TOCWidget? Maybe I can use it or just use the code inside of it that is making the exclude work.

Edit: I found the widget - Roberts.

Robert it looks like you give toc.excludelayers a Object that is the layer name, and id array, and basemap false? Any hint into how you made this work would be great.

Thanks

RhettZufelt

Rhett,

I guess the only thing you missed is that Doug is not talking about the TOCWidget.

Guess I should read the posts a little better 🙂

R_

John_Jones_0-1633396660739.png

dougbrowning

Did you modify the toc.exludelayers?

I am trying just this as a test but it is not working.

   excludedLayers = new ArrayCollection;

    var excludes:Object ={
     name: "MapTest",
     ids: [1,2,3,4,5],
     isbasemap: false
    }

    excludedLayers.addItem(excludes);
    toc.excludeLayers = excludedLayers;

Thanks

RobertScheitlin__GISP

Doug,

You will have to dig into the code and look as there was multiple places that I added code to exclude sub layers.

RhettZufelt

Yes, I can succesfully manipulate the toc.excludeLayers, but is very specific about it's "needs".

If you tell it to remove a sublayer that isn't there, it ignores.
If you tell it to remove all ids, it will remove them, but keep the name in the TOC. need to exlude the layername without any sublayers defined if you want to completely remove from the TOC.

Might put a couple trace statements in as such:

      if(idsArray[0] == "")
       idsArray = null;
      var excludes:Object ={
       name: name,
       ids: idsArray,
       isbasemap: false
      }
      trace("excludes.name ",excludes.name);
      trace("excludes.name ",excludes.ids); 
             excludedLayers.addItem(excludes);

and change the excludlayer tag settings in the config to get an idea of the syntax/formatting required. But, if you get it right, it works.

I am not using any basemaps in my TOC, so I didn't have to mess with that section, I just let it add all basemaps to the exclude list, but as Robert mentioned, you would have to modify it anywhere that it getting called.

R_

On my LayerListWidget, I modified the toc.as portion of it to only add layers in the excluded layers list. Was a lot easier as my list to exclude was much larger than the list to include.

RhettZufelt

Doug,

Re-read the posts, and not quite sure what you need. If you are trying to do this programatically, then you would want to have a go at the excludedLayers array.

However, it sounds kind of like you just want to be able to statically pick which layers/sublayers show in the TOC. If that is it, Robert has the excludelayer tag in the config.xml that lets you exclude either a layer, or some/all of the sublayers. No coding required.

R_

dougbrowning

Thanks R_. I do not think they (the ups) are going to want to use his widget so I have to recreate just that part.

I am surprised this was not build in from the beginning. It is confusing that the <layer> tag is used for a map service. Roberts is so much easier to understand (I have this map service and I want these layers from it).

We will also be bringing in layers from other organizations and we may want to have one of the layers from their map service listed in one spot and another somewhere else.

I keep going to exclude layers like you say but i would really like to have a blank map and then load in layers as I go (since there will be 1,000+ layers over many map services - some in house, some not). Just like how ArcMap works, you start with a blank TOC and then add in layers using a Add Data button - you think esri would have made them similar. But when i drill down in the code to where a layer is actually added I eventually hit a spot where the source code is no longer supplied. I have another feature that lets a user save the list of layers they picked out so that say the next day they can reload and keep working or send it to someone else (a save map). I have it working with using exclude but the file is weird to look at since it actually lists the opposite of what they had.

I am trying to build the biggest web map ever but the code assumes just a little simple one is the issue I think.

I will go through Roberts code a 5th time and see if I can find it.

Thanks again.

RobertScheitlin__GISP

Doug,

I believe I have the functions named pretty straight forward... Look for stuff like filterOutSubLayer

dougbrowning

I do not have the full solution done but thought I would post this as it may help someone.

I found down in TOCMapLayerItem.as

    a function called createChildren() where the layers in the map service are added I was able to add an if statement here to only list the layers (children) I want. It just works off a global var for now (I know that is cheating).

my new code is under the else in the adding of dynamic map service layers section

else
            {
             /* OLD layerInfos = _dynamicMapServiceLayerInfos;*/
    /* added by me */
    layerInfos = [];
    for each (var layerInfo:LayerInfo in _dynamicMapServiceLayerInfos)
    {


     if (Application.application.SubLayers.indexOf(layerInfo.name) != -1)
     {
      layerInfos.push(layerInfo);
     }

    }

I might need to add this above the else, if _isVisibleLayersSet is ever used but it does not seem to be used so far?

It does work in my demo great. Going to work on an option to remove the map service name from the mapswitcher widget as well using toc.categories.

Thanks for the help and I will post the full solution when i get it.

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