topic Re: Resampling option for ArcGISTiledMapServiceLayer in ArcGIS JavaScript Maps SDK Questions

Resampling option for ArcGISTiledMapServiceLayer

DaveTimmins — Mon, 06 Jan 2014 18:29:30 GMT

Hi,

I have a question regarding the resampling option that was added at v3.6 as per the documentation at https://developers.arcgis.com/en/javascript/jsapi/arcgistiledmapservicelayer-amd.html#arcgistiledmapservicelayer1. My question is does it work? I put together a jsfiddle at http://jsfiddle.net/vVUF6/ that has 2 tiled services in the same projection but with differing LODs. They are both served by the same ArcGIS Server running v10.2.0. I have explicitly set the LODs for the map (though not setting this makes no difference) and you can see that the only scale that both services display is the 1:50,000 scale. This is the only one where the LODs match. I can also see that at this scale the query parameter for blankTile is appended to the second tiled service with a value of false.

Any ideas or comments?

Cheers,

Re: Resampling option for ArcGISTiledMapServiceLayer

JianHuang — Mon, 06 Jan 2014 19:33:38 GMT

Dave,

Resampling doesn't mean it can resample to any scale. The only purpose of resampling is to enlarge the image and fill in at the levels where there are no tiles available.
For example, the street map tiled layer may not have data beyond level 15 in some area. But in other areas (metropolitan areas), it may have data till level 19. Enabling resampling would draw images all over to the last level and deliver consistent user experience. Of course in the area with no data, you will get blurred images.
Another words, it doesn't work with user's provided LODs.

Re: Resampling option for ArcGISTiledMapServiceLayer

DaveTimmins — Mon, 06 Jan 2014 19:42:42 GMT

Hi Jian,

as I mentioned, specifying the LODs or not makes no difference. If you look at the available LODs for those services, the one that I have enabled resampling for only goes down to 1:25,000 whereas the basemap goes to 1:2,500 so from what you have said it sounds like if I zoom in beyond 1:25,000 I should see the second tiled service albeit blurred. is that correct? If so what is stopping it from working that way for intermediate scale levels where the second service doesn't match the basemap?

Do you have an example that works as you have mentioned?

Cheers,

Re: Resampling option for ArcGISTiledMapServiceLayer

JianHuang — Mon, 06 Jan 2014 20:51:06 GMT

Here is an example:
http://jsfiddle.net/jian/f6g5H/
You will notice many erros in console starting from level 14, meaning resampling is happening.

Re: Resampling option for ArcGISTiledMapServiceLayer

DaveTimmins — Mon, 06 Jan 2014 21:28:28 GMT

Hi Jian,

thanks for that, so as I understand it now the resampling is only useful for services that have varying coverage at larger scale levels. Not that clear that it works that way from the documentation plus since SL and Flex can do intermediate resampling I was hoping this would be the same. Nevermind.

Cheers,