Read a webmap service that contain a raster layer

If it's a WMS service, then you can simply use the regular WMS reader.

WMS services always returns a raster regardless of the source data type, so there should be no difference from the client side.

Hi @david_r ,

Thanks for replying.

When I used the WMS reader, I got a pixelated raster and I need it to be exact to the map service. How could I download the raster to be fine with all resolutions?

And I have this layer as a map service not WMS layer, Could I do anything to download the raster from regular map service to have a good resolution?

Thanks,

Rawan

Hi Rawan

It's difficult to say without knowing more about the server and how it's configured. Also, I'm not quite sure I understand the distinction between WMS and "map service" (WMS = web map service) in this context.

If the WMS reader returns a raster, I'm guessing it's indeed a WMS, otherwise you'd most probably get a server error.

The raster that's returned by the WMS reader will depend heavily on how the server has been configured, and in particular the source raster resolution. For example, if the server has a source orthophoto with 50m/pixel resolution and you request an area that's 200 x 200 meters across, the returning raster would only contain 4 x 4 pixels. Of course this is an exaggerated example, but you get the idea.

In short, you may want to contact the person responsible for the server (or see if there's any detailed documentation) that can help you further.

Also, if this is a public web service, feel free to post the URL here so that we can experiment with it.

Thanks for replying @david_r

I’m trying to download a public map service and they provide it in two format

1: ArcGIS Server map service : http://services.ga.gov.au/site_9/rest/services/NEXIS_Residential_Population_Density/MapServer

2. WMS Map service: http://services.ga.gov.au/site_9/services/NEXIS_Residential_Population_Density/MapServer/WMSServer?request=GetCapabilities&service;=WMS

And when I tried to use the WMS reader to download the raster I got it pixelated and not exact the map service (I need it to be clear when I zoom in and out), and I don’t want it to be in ECW format because I will publish this raster to my ArcGIS Server and the ECW format not supported.

If you can help me in this I will be so glad.

Cheers,

Rawan

When you say "I need it to be clear when I zoom in and out", do you perhaps refer to looking at the raster in the FME Inspector? If so, be aware that FME and e.g. ArcMap behaves fundamentally different when accessing a WMS or an ArcGIS Map Service.

When you zoom in and out in ArcMap (or QGIS, etc), it will actually request a new raster from the server each time you zoom or pan. This makes it possible for the server to tailor the resulting raster to the exact dimension and zoom level of the client. So if the server has many rasters in different resolutions (or rasters with pyramids) it will be able to base the result on the raster that is the best fit for each request, depending on the zoom level etc.

On the other hand, FME will only make the request once and the send the resulting raster to the Inspector. When you zoom in and out inside the FME Inspector, you only zoom in and out of the exact same raster, there are no new requests made to the server. If you need different rasters for different zoom levels in FME, you'll have to author the workspace so that it specifically makes a separate request for each zoom level that you need.

Does this make sense? Let me know if I've misunderstood.

If you only need to publish this service to your own ArcGIS Server, wouldn't the easiest solution be to create an mxd that references the existing service and publish it on your own server?

If that isn't an option you'll need create lots and lots of small polygon tiles (Tiler) and send each of them to e.g. the FeatureReader. It's going to be a bit of work to puzzle everything together so that your workspace settings are optimized for the server configuration (zoom levels, resolutions, etc.)

If all else fails, perhaps it would be an idea to ask the map service provider if the data also exists as a feature layer (raster), or perhaps even as a file download that you can access.