topic esri map tag in ArcGIS API for Flex Questions

esri map tag

NadeemQazi — Wed, 29 Aug 2012 09:20:47 GMT

Hi

I used following code
<esri:Map id="myMap"
     crosshairVisible="true"
     level="3">
<esri:ArcGISDynamicMapServiceLayer url="http://149.157.138.198/ArcGIS_Server/rest/services/davesite/MapServer"/>
</esri:Map>
it works but it does not show the scale bar only a + and - sign is shown however when i used it with the esri map address such as :
   <esri:ArcGISTiledMapServiceLayer maxScale="4500" url="http://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer"/>
     it also shows me the full scale bar any suggestion what s wrong
regards
nadeem

Re: esri map tag

RobertScheitlin__GISP — Wed, 29 Aug 2012 11:05:27 GMT

Nadeem,

That is because an ArcGISDynamicMapService does not have any predefined LODS and thus does not require a Zoom Slider (quite different than a scalebar). A ArcGISTiledMapService on the other hand does have set scale levels (LODs) that the map will only draw at these levels and thus needs a Zoom Slider.

Don't forget to click the Mark as answer check on this post and to click the top arrow (promote).
Follow the steps as shown in the below graphic:

Re: esri map tag

DasaPaddock — Wed, 29 Aug 2012 17:07:13 GMT

See this sample:
http://resources.arcgis.com/en/help/flex-api/samples/index.html#/Only_use_some_scales_LODs/01nq0000005v000000/

Re: esri map tag

NadeemQazi — Thu, 30 Aug 2012 08:40:18 GMT

Nadeem,

That is because an ArcGISDynamicMapService does not have any predefined LODS and thus does not require a Zoom Slider (quite different than a scalebar). A ArcGISTiledMapService on the other hand does have set scale levels (LODs) that the map will only draw at these levels and thus needs a Zoom Slider.

Don't forget to click the Mark as answer check on this post and to click the top arrow (promote).
Follow the steps as shown in the below graphic:

Thanks robert for reply however i am bit confused. Should I assume that I need to use ArcGISTiledMapService for a zoom slider and
ArcGISDynamicMapService does not have any zoom slider. Whats the difference between these two services. I appreciate your help.
regards
nadeem

Re: esri map tag

RobertScheitlin__GISP — Thu, 30 Aug 2012 11:22:10 GMT

Nadeem,

There is a pretty big difference between the two. An ArcGISDynamicMapService does not have defined LODs (scale ranges that the map has be cached at) and thus you can zoom the map to a scale of 1444444 or 1444456. This is why it does not have a zoom slider, it only has a zoomin and zoomout button. Each time the map is paned or zoomed a request is made to ArcGIS Server using the current extent of the view area of the map and ArcGIS Server produces image(s) that are returned to draw in the map.

An ArcGISTiledMapService has predefined LODs (zoom scale) where the map has pre-generated images (tiles) that are fetched base on the maps LOD and extent and thus fetching a tile (already produced image) is much quicker than ArcGIS Server has to produce the image on each request. You can not use a ArcGISTiledMapService unless you have already gone though the process of producing a tile cache. Though an ArcGISTiledMapService is much faster to draw it is limited to those defined LODs and it will not attempt to re-project those tiles to a different WKID, where the ArcGISDynamicMapService will re-project it's data based on the requested WKID.

There is really nothing I have covered here that you could not have learned for yourself by reading the documentation.

So the question is do you have a real need for the zoom slider or do you just think you need it? In 2 of my production site for my county I do not use cached maps at all as I have my 3 ArcGIS Servers optimized to produce maps using ArcGISDynamicMapServices and they return the map very fast, and I am not limited to the scales that the map can be zoomed to because of LODs.

Re: esri map tag

JeffersonFerreira_Ferreira — Mon, 24 Sep 2012 14:33:39 GMT

Hi all;

Robert, you're completely right but I've have seen many implications in mapping with no LODs. One of them is visual, 'cause when there are no LODs the scale bar disappear in the application. The another implications are related to widgets you use. An exemple: The PCHPrintSOE crashes in these case. We need to configure at widget xml the scale of the print area that relates to paper format to show the printed area at viewer. When there are no LODs the application apparently doesn't compute any scale and the zoom applied is not in terms of scale but only a zoom itself. As result the print area of PCHPrintSOE It's show wrong as a largest area than the area of interest. So at my experience It's complicated to work without it because it will affect many other functions.

Re: esri map tag

RobertScheitlin__GISP — Mon, 24 Sep 2012 14:49:33 GMT

Jefferson,

Well I have to disagree with this statement:

cause when there are no LODs the scale bar disappear in the application

You can absolutely have a scale bar in a application that only uses ArcGISDynamicMapServiceLayers. As for the PCHPrintSOE well there are sometimes draw backs to using third party widget.

Re: esri map tag

JeffersonFerreira_Ferreira — Mon, 24 Sep 2012 17:35:50 GMT

Jefferson,

Well I have to disagree with this statement: (...)

Robert, are you sure? Always I've used only my image services (not cached; type="image") the scale bar disappear and there are no scales at zoom tool, only the + and - buttons and I had even accepted this fact.

Re: esri map tag

RobertScheitlin__GISP — Mon, 24 Sep 2012 17:44:33 GMT

Jefferson,

Now this is where your improper use of terms is hurting you.

cause when there are no LODs the scale bar disappear in the application

The Scale bar is this:[ATTACH=CONFIG]17934[/ATTACH]
and what you are referring to is the zoomslider:
[ATTACH=CONFIG]17935[/ATTACH]

And Image service does not have LODS either thus no ZoomSlider.

Re: esri map tag

JeffersonFerreira_Ferreira — Mon, 24 Sep 2012 18:02:59 GMT

Robert, thanks for your response. In fact I've posted the response to you and I soon realized my mistake. What I'm not wrong in what I'm trying to say. The scale bar and zoom slider really disappear, but how can I have zoomslider and scale bar if what I have is a default image service?! Sorry, you are correct. There are no LOD's in a default image service.

Re: esri map tag

RobertScheitlin__GISP — Mon, 24 Sep 2012 18:08:39 GMT

Jefferson,

So let me be sure of something here than. Are you talking about a custom API application of the Flex Viewer? Because the direction provided will be different.

Re: esri map tag

JeffersonFerreira_Ferreira — Mon, 24 Sep 2012 18:16:48 GMT

Jefferson,

So let me be sure of something here than. Are you talking about a custom API application of the Flex Viewer? Because the direction provided will be different.

Well I'm not certain how far my application may be considered custom. The application itself is the flexviewer api available to download. What I've customized are the widgets, the projection and visual elements. I hope I have answered your question.

Re: esri map tag

RobertScheitlin__GISP — Mon, 24 Sep 2012 18:29:55 GMT

Jefferson,

Just so you know and that is does not become a point of confusion in the future. The Flex Viewer as an application that is built using the AGS Flex API. When someone asks if you are working with a custom API application or the flex viewer, they are trying to determine if you have Only used the AGS Flex API components and built a Flex Application from scratch, not just customizing the viewer.

So, I understand your issue to be that you are loading a image service as your first basmap and thus it is using your image services WKID to set your maps spatial reference. So my fist question would be are you using a tiled basemap at all in your flex viewer and if so why are you not loading that service first? Are all your services (i.e. image service and tiled map service) in the same WKID?

Re: esri map tag

JeffersonFerreira_Ferreira — Mon, 24 Sep 2012 18:51:45 GMT

Jefferson, (...)

So, I understand your issue to be that you are loading a image service as your first basmap and thus it is using your image services WKID to set your maps spatial reference. So my fist question would be are you using a tiled basemap at all in your flex viewer and if so why are you not loading that service first? Are all your services (i.e. image service and tiled map service) in the same WKID?

Robert.

Thanks for your explanation about flex viewer and custom api issues.
Well, I've tried firstly to use bing tiled services. But I have problems with map WKID, that need to be 4326. So I gave it up and decided to use only my satellite images serving them in ArcGIS Server. As result I have no more tiled services. My mapservice is not tiled too 'cause I dont see this need. All the map services and image services are at the same WKID. Now I understand that my current situation prevents me from using LOD's and thus I dont have the scale bar and zoom slider. I'm reading the documentation right now to decide what capabilities I must enable to serving my images more efficiently.

Re: esri map tag

RobertScheitlin__GISP — Mon, 24 Sep 2012 19:01:32 GMT

Jefferson,

So it is possible to manually load LODs in the Flex Viewer App by defining the LODs you want in the Main config.xml. Search this link for lods:

http://resources.arcgis.com/en/help/flex-viewer/concepts/index.html#/Main_configuration_file/01m300000018000000/

Re: esri map tag

JeffersonFerreira_Ferreira — Mon, 24 Sep 2012 19:16:13 GMT

Jefferson,

So it is possible to manually load LODs in the Flex Viewer App by defining the LODs you want in the Main config.xml. Search this link for lods:

http://resources.arcgis.com/en/help/flex-viewer/concepts/index.html#/Main_configuration_file/01m300000018000000/

Thanks Robert. I'll consider it.