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Maps in Two Projections

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06-02-2010 11:26 AM
BradOleson
Emerging Contributor
I have a need to view my maps in the Flex Viewer (or are we calling it Flash Viewer now?) in UTM 11N.  I need the data from the MGRS to be correct and that is projected to UTM.  Printed maps will be used to navigate using the MGRS.  However, the basemap (ESRI StreetMap, etc) is the WGS 84 projection.  How would this best / most easily be handled?

Thanks in advance...

Brad
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14 Replies
ZahidChaudhry
Deactivated User
I have a need to view my maps in the Flex Viewer (or are we calling it Flash Viewer now?) in UTM 11N.  I need the data from the MGRS to be correct and that is projected to UTM.  Printed maps will be used to navigate using the MGRS.  However, the basemap (ESRI StreetMap, etc) is the WGS 84 projection.  How would this best / most easily be handled?

Thanks in advance...

Brad

All the new services from ESRI are in web mercator. WGS 84 will phase out in near future.
Easiest way is to use your own base maps and then you do not need to worry about projection issues.
Although, if you want to use ESRI's base maps, you can use your dynamic map layers and server will reproject them on fly to web mercator and you will be fine but you can not do this if your map services are cached.
Bottom line is as long as your data is dynamic, it is not an issue and it will display
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RobertScheitlin__GISP
MVP Emeritus
Brad,

   Zahid is correct, it is best just to have your own basemaps when working with your own specific projection. One thing to add to what Zahid said though is you can use ESRI base maps in WGS 1984 that are cached as long as you add them as dynamic map services and not tiled. If you add a cached map service as a dynamic map service then the cache is ignored and ArcGIS Server will reproject on the fly. That being said you have to either specify the Extent with the UTM Spatial Reference or ensure you add your UTM map service as the first layer. The preformance of this app would be hindered though as ArcGIS Server will have to reproject evry map call.
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BradOleson
Emerging Contributor
Ok, let's expound on that a little, then:

In my config file I now have moved the StreetMap layer into the livemaps portion of config.xml:
<mapservice label="Street Map" type="dynamic" visible="true" alpha="1" icon="com/esri/solutions/flexviewer/assets/images/icons/i_highway.png">http://server.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer</mapservice>
          <mapservice label="NVNG Imagery" type="dynamic" visible="true" alpha="1">http://ngnv-jhqj6-a014/ArcGIS/rest/services/NVNG_Site_Imagery/ImageServer</mapservice>
          <mapservice label="NVNG Facilities" type="dynamic" visible="true" alpha="1">http://ngnv-jhqj6-a014/ArcGIS/rest/services/NVNG_Web_Mapping/MapServer</mapservice>

This results in listing the services in this order in the layers widget:
NVNG Facilities
NVNG Imagery
Street Map

My first question is why the order gets reversed between the config file and the widget.  The second question is: does this mean the UTM layer (NVNG Facilities) is loaded first and the projection should thus be in UTM in Flex?  If so, it doesn't seem so, since my UTM Grid is not "square" on the screen.  Please shine a little more light on this for me?  Thanks!

Brad
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RobertScheitlin__GISP
MVP Emeritus
Brad,

   What does the initialExtent and fullExtent in your config file look like?
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BradOleson
Emerging Contributor
Here it is:

<map initialExtent="-120.2 34.6 -113.8 42.2" fullExtent="-150 -50 150 50">
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RobertScheitlin__GISP
MVP Emeritus
Brad,

   Those are WGS84 coordinates... If you want your map to be in UTM then you have to tell it that by setting the extent in UTM and making sure that the first map service loaded is UTM.
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BradOleson
Emerging Contributor
Gotcha.  I will change them.  But which is the "first service loaded", per my previous reply?
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RobertScheitlin__GISP
MVP Emeritus
Brad,

   Based on the order of your previous post the Map would get a SR of the Street map (WGS84) because that is the first one listed in the config.xml.
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BradOleson
Emerging Contributor
Ok...so riddle me this: why does the widget show them in reverse order from how they are loaded in the config.xml?
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