esri map tag

[NadeemQazi]

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

[RobertScheitlin__GISP]

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:

[DasaPaddock]

See this sample:
http://resources.arcgis.com/en/help/flex-api/samples/index.html#/Only_use_some_scales_LODs/01nq00000...

[NadeemQazi]

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

[RobertScheitlin__GISP]

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.

[JeffersonFerreira_Ferreira]

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.

[RobertScheitlin__GISP]

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.

[JeffersonFerreira_Ferreira]

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.

[RobertScheitlin__GISP]

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.

[JeffersonFerreira_Ferreira]

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.