topic Re: Grainy Raster Dataset in Flex, but not in ArcMap??? in ArcGIS API for Flex Questions

Grainy Raster Dataset in Flex, but not in ArcMap???

TonyCollins — Mon, 21 Mar 2011 19:56:46 GMT

Hi, I have two Raster Datasets containing Aerial Photography. They has been created on Server 9.3.1.

One of them appears perfectly from Flex, but the other appears really grainy like a heavily compressed JPEG.

Both of these appear fine in ArcMap when using Direct Connect or the actual ArcGIS Server service the Flex API is using?

Re: Grainy Raster Dataset in Flex, but not in ArcMap???

TonyCollins — Tue, 22 Mar 2011 08:59:37 GMT

If you look closely at this image you can see what I mean. Look in the bottom left at the grass to see:

The image quality is identical in Arcmap when calling from the database or using the ArcGIS service, but when viewed through the API it goes grainy like above.

HELP!!!

Re: Grainy Raster Dataset in Flex, but not in ArcMap???

RobertScheitlin__GISP — Tue, 22 Mar 2011 11:19:52 GMT

Tony,

Are you adding them to the map as a ArcGISDynamicMapServiceLayer? If so have you tried to set the imageFormat="jpg" and dpi="150"? This is what I do for my Imagery layers.

Re: Grainy Raster Dataset in Flex, but not in ArcMap???

TonyCollins — Tue, 22 Mar 2011 11:56:14 GMT

Tony,

Are you adding them to the map as a ArcGISDynamicMapServiceLayer? If so have you tried to set the imageFormat="jpg" and dpi="150"? This is what I do for my Imagery layers.

Hi Robert,

You are a STAR!!!

One thing though, I have had to use PNG24 as this layer is scale dependant and when the layer should not be shown the whole screen goes white. I am asuming this is because the API makes the layers transparent or something when they should not be visible (which JPG does not support)??

Does this sound right to you?

Re: Grainy Raster Dataset in Flex, but not in ArcMap???

RobertScheitlin__GISP — Sun, 12 Dec 2021 04:17:46 GMT

Tony,

Yep that's why I actually use these lines in my code:

if(label == "Aerial Photography")
      {
       dynLayer.imageFormat = "jpg";
       dynLayer.dpi = 150;
       dynLayer.minScale = 10000;
      }

Re: Grainy Raster Dataset in Flex, but not in ArcMap???

TonyCollins — Sun, 12 Dec 2021 04:17:49 GMT

Tony,

Yep that's why I actually use these lines in my code:

if(label == "Aerial Photography")
      {
       dynLayer.imageFormat = "jpg";
       dynLayer.dpi = 150;
       dynLayer.minScale = 10000;
      }

Thanks Robert,

Do you know whether the image format I specifiy is done on the client or ArcGIS Server? I think I would prefer using PNG24 to stop the white area you get whilst the layer loads but I definately don't want any extra load on the server?

Re: Grainy Raster Dataset in Flex, but not in ArcMap???

RobertScheitlin__GISP — Tue, 22 Mar 2011 13:34:26 GMT

Tony,

I am pretty sure it is server side. Which means larger images/bytes that are to be transferred to the client if PNG 24.

Re: Grainy Raster Dataset in Flex, but not in ArcMap???

TonyCollins — Tue, 22 Mar 2011 13:40:42 GMT

Tony,

I am pretty sure it is server side. Which means larger images/bytes that are to be transferred to the client if PNG 24.

Oh Ok, I shall have to do some testing.
Thanks as always Robert, you helped me hugely!!!