LAYERINFO

Used in

Servers

Image Query Feature Extract Geocode ArcMap

Parent elements

Syntax

<LAYERINFO	Attribute Description Table
When using ArcMap Server: arcmaptype="string" [group \| annotation \| multipatch] parentlayerid="string" When using Image and ArcMap Server: *(r)id="string"* maxscale="string" minscale="string" name="string" type="featureclass \| image \| acetate" visible="true \| false" > When parent element is LAYERINFO and type is acetate: (m)<OBJECT... /> [Image Services only] When parent element is LAYERINFO and type is featureclass for ArcMap Image Services: <FCLASS... /> When parent element is LAYERINFO and type is featureclass for Image or Feature Services: (r)<FCLASS... /> <EXTENSION... /> <GROUPRENDERER... /> <SCALEDEPENDENTRENDERER... /> <SIMPLELABELRENDERER... /> <SIMPLERENDERER... /> <VALUEMAPLABELRENDERER... /> <VALUEMAPRENDERER... /> When parent element is LAYERINFO and type is image: <ENVELOPE... /> <RASTER_RENDERER... /> [Image Services only] When using ArcMap Server: <TOC... /> </LAYERINFO >
(r): Attribute or child element is required. (m): Child element can be used multiple times.

Description

Defines layer information such as ID and name, minimum and maximum scale, layer type, and whether the layer is visible.

Notes

When GET_SERVICE_INFO relativescale="false", or relativescale is not included in the request, scales in LAYERINFO are calculated based on the number of map units per pixel. In requests and the map configuration file, scales can be set using a relative scale ratio such as 1:24000. In this example, 1 meter equals 24000 meters or 1 inch equals 24000 inches.

Map units per pixel refers to the number of meters, feet, or decimal degrees represented by one pixel in a map. To convert from a relative scale to map units per pixel, the size of a pixel must first be calculated. The formula for finding the number of meters in a pixel is 0.0254 / dpi where:
- The value 0.0254 is the number of meters in an inch.
- Dpi is the dpi set in the service or request. If no dpi is set in the ArcIMS service or request, the dpi is assumed to be 96.
As an example of calculating pixel size, if the dpi is 96, the pixel size is 0.0254 / 96 or 0.000265 m.

Once the pixel size is known, the relative scale can be converted to map units per pixel:
1. If the scale is in meters. To calculate the number of meters per pixel, take the relative scale and multiply by the pixel size (0.000265). For example, if the relative scale is 1:24000, then the number of meters per pixel is 24000 * 0.000265, or 6.36 meters.
2. If the scale is in feet. Do the calculation for meters (#1). Multiply the result by 3.28 (the number of feet in a meter). For example, if the number of meters per pixel is 6.36, the number of feet per pixel is 6.36 * 3.28, or 20.86 feet.
3. If the scale is in decimal degrees. For these calculations, the Earth is assumed to be an exact sphere with a circumference of 40030.174 km. One degree is 111.195 km (40030.174/360 degrees) or 111195 meters. To calculate the number of degrees, first do the calculation for meters (#1). Next, divide the result by 111195. For example, if the number of meters per pixel is 6.36, the number of degrees per pixel is 6.36 / 111195, or 0.0000571968.

When referencing group layers in an ArcMap Image Service, you must understand the relationship between id and parentlayerid. The parent layer is the group layer name and can have one or more layers referencing it.

The following example includes two sets of grouped layers. A group layer called "Country Map" is nested in another group layer called "WorldData". In the SERVICEINFO response, the LAYERINFO list ordered from bottom-most layer to top-most layer. Thus, the layer representing the group layer is listed after all the other layers within the group.

If you reverse the order of the layers, you will see that the list of layers and group layers reflects what you would see in the TOC in ArcMap. The "cities" layer with id="0" is not part of any group layer. The "WorldData" layer with id="1" is the outer group layer. Layers that fall within this group layer are "latlong", "rivers", and "Country Map". These layers have parentlayerid="1", which references the "WorldData" layer. "Country Map" is a second group layer nested inside "WorldData". Layers in the "Country Map" group include "wsiearth.tif", "country", and "lakes". These layers all have parentlayerid="4", which references the "Country Map" layer.

A parent-child relationship for annotation layers in an ArcMap Image Service is defined using parentlayerid and id. In the following example, two layers representing one annotation layer is defined in a SERVICEINFO response. The annotation layer name is "BlockgroupsAnno" and is defined as an annotation layer since arcmaptype="annotation". The annotation "Default" layer has parentlayerid="7", which means this layer is a child layer to "BlockgroupsAnno".

<LAYERINFO type="image" parentlayerid="7" name="Default" id="8" visible="true"></LAYERINFO>
<LAYERINFO type="image" arcmaptype="annotation" name="BlockgroupsAnno" id="7" visible="true"></LAYERINFO>

Attribute Descriptions for LAYERINFO

Attribute	Usage
arcmaptype	Returned for ArcMap Image Services when a layer is a group layer, annotation layer, or multipatch layer.
parentlayerid	Returned for ArcMap Image Services for each layer that belongs to a group in LAYERINFO. This includes annotation layer. Group layers can be nested.
id	Reference to unique layer ID as defined in map configuration file or ArcMap document.
maxscale	Maximum scale to display map. Does not apply unless maxscale is set in the service. When scale values are returned as a relative scale, values are not rounded when the map is in decimal degrees.
minscale	Minimum scale to display map. Does not apply unless minscale is set in the service. When scale values are returned as a relative scale, values are not rounded when the map is in decimal degrees.
name	Layer name as defined in map configuration file or ArcMap document.
type	Shows type of layer as defined in map configuration file or ArcMap document.
visible	Specifies whether or not layer is visible.

Examples for LAYERINFO

<?xml version="1.0" encoding="UTF-8"?>
<ARCXML version="1.1">
  <RESPONSE>
    <SERVICEINFO>
      <ENVIRONMENT>
        <LOCALE language="en" country="US" />
        <UIFONT name="Arial" color="0,0,0" size="12" style="regular" />
        <SEPARATORS cs=" " ts=";"/>
        <CAPABILITIES forbidden="" disabledtypes=""/>
        <SCREEN dpi="96"/>
        <IMAGELIMIT pixelcount="1048576" />
      </ENVIRONMENT>
      <PROPERTIES>
        <FEATURECOORDSYS id="4326"/>
        <FILTERCOORDSYS id="4326"/>
        <ENVELOPE minx="-180" miny="-90" maxx="180" maxy="90" name="Initial_Extent" />
        <MAPUNITS units="decimal_degrees" />
      </PROPERTIES>
      <LAYERINFO type="featureclass" visible="true" name="Countries" id="1">
        <FCLASS type="polygon">
          <FIELD name="AREA" type="8" size="12" precision="3" />
          <FIELD name="NAME" type="12" size="40" precision="0" />
          <FIELD name="ABBREVNAME" type="12" size="12" precision="0" />
          <FIELD name="FIPS_CODE" type="12" size="2" precision="0" />
          <FIELD name="WB_CNTRY" type="12" size="3" precision="0" />
          <FIELD name="HYPERLINK" type="12" size="60" precision="0" />
          <FIELD name="#SHAPE#" type="-98" size="0" precision="0" />
          <FIELD name="#ID#" type="-99" size="16" precision="0" />
        </FCLASS>
      </LAYERINFO>
      <LAYERINFO name="NorthArrow" visible="true" id="NorthArrow"<
        <OBJECT units="pixel">
          <NORTHARROW type="4" coords="20 30" shadow="32,32,32" size="15" angle="0" antialiasing="true" overlap="false" />
        </OBJECT>
      </LAYERINFO>
    </SERVICEINFO>
  </RESPONSE>
</ARCXML>