Scale Hint

[myopic]

I am wondering how the scale hint property can be modified. Can you specify in the cat-cfg file a scale hint or maxscaledenominator property? We are using WMS and I understand the 'scale hint' has been replace with max/minscaledenominator in the new WMS format (1.1.1)..

Any ideas?
Currently my Cat-cfg.xml entry is this..

<Catalog name="040">
<Property name="wms-layer-Title">
<Title>2004 Natural Colour UTM 10</Title>
</Property>
<Provider name="file" root="\imgwhse\2004\utm10" volume="\\hemlock\dim2_prod19"/>
<Property name="wms-layer-list-SRS">EPSG:3005,EPSG:4326,EPSG:32608,EPSG:32609,EPSG:32610,EPSG:32611</Property>
<SpatialIndex classID="{D090DD8B-3D12-4631-9787-0DC2CACDC3EA}"/>
</Catalog>

But the Capabilities returns this..

<Layer opaque="1">
<Name>040</Name>
<Title>2004 Natural Colour UTM 10</Title>
<SRS>EPSG:32610</SRS>
<SRS>EPSG:3005</SRS>
<SRS>EPSG:4326</SRS>
<SRS>EPSG:32608</SRS>
<SRS>EPSG:32609</SRS>
<SRS>EPSG:32610</SRS>
<SRS>EPSG:32611</SRS>
<LatLonBoundingBox maxx="-119.510726" maxy="55.702477" minx="-124.822557" miny="48.985031"/>
<BoundingBox SRS="EPSG:32610" maxx="719514.500000" maxy="6172990.500000" minx="385427.500000" miny="5430130.500000" resx="1.000000" resy="-1.000000"/>
<BoundingBox SRS="EPSG:3005" maxx="1439244.674431" maxy="1202790.469135" minx="1073863.083574" miny="445187.094583"/>
<BoundingBox SRS="EPSG:4326" maxx="-119.510726" maxy="55.702477" minx="-124.822557" miny="48.985031"/>
<BoundingBox SRS="EPSG:32608" maxx="1595640.093201" maxy="6276839.701913" minx="1138590.035010" miny="5481610.171408"/>
<BoundingBox SRS="EPSG:32609" maxx="1158132.121673" maxy="6208379.154637" minx="762540.374612" miny="5438421.781128"/>
<BoundingBox SRS="EPSG:32611" maxx="342030.087589" maxy="6199254.051174" minx="-53084.608797" miny="5430127.731908"/>
<ScaleHint max="362.038672" min="1.414214"/>
</Layer>

Many Thanks!
Michelle

[rparker]

wms-layer-ScaleHint

The Image Server calculates the value of the ScaleHint element for each layer based on the contents of the catalog that the layer represents. One can override the calculated value by setting the property wms-layer-ScaleHint for the catalog.

Example:

<CatalogConfig>

<Catalog name="foo">

...

<Property name="wms-layer-ScaleHint"><ScaleHint max="512" min="1"/></Property>

...

</Catalog>

...

</CatalogConfig>

[myopic]

Thanks Robert.
It works great.
I think I understand now..

The WMS defines the scalehint values as the ground distance in meters of
the southwest to northeast diagonal of the central pixel of a map.
ScaleHint values are the min and max recommended values of that
diagonal. (See WMS 1.1.0 sect. 7.1.5.4)


The ScaleHint units aren't defined by the spec, but looking at the code, layer can be served at scales that result in pixel diagonal sizes defined by the scalehint range.

In the WMS 1.2/1.3 spec (to be released soon hopefully), the ScaleHint
will be replaced by MinScaleDenominator and MaxScaleDenominator which
makes much more sense. You can already find the definition of those two
elements in the SLD 1.0 specification.

[myopic]

I have one other question. Express Server, by default, calculates the Scale Hint.. is there any way to turn this off completely (ie. have the layer display at all scales?) The WMS specifications do not specify it as mandatory... (Section 7.1.4.5.8 ScaleHint
Layers may include a <ScaleHint> element that suggests minimum and maximum scales
for which it is appropriate to display this layer.)

Regards,
Michelle

[vinhmx]

<Property name="wms-layer-ScaleHint"><ScaleHint max="512" min="1"/></Property>
Can you explain that function of "wms-layer-Scalehint" ?