Identify - Image Service (Operation)

URL	`http://<imageservice-url>/identify`
Parent Resource	Image Service
Required Capability	Image

Description

The identify operation is performed on an image service resource. It identifies the content of an image service for a given location and a given mosaic rule. The location can be a point or a polygon.

The identify operation is supported by all kinds of image services (Mosaic Datasets, Raster Datasets).

The result of this operation includes the pixel value of the mosaic for a given mosaic rule, a resolution (pixel size), and a set of catalog items that overlap the given geometry. The single pixel value is that of the mosaic at the centroid of the specified location. If there are multiple rasters overlapping the location, the visibility of a raster is determined by the order of the rasters defined in the mosaic rule. It also contains a set of catalog items that overlap the given geometry. The catalog items are ordered based on the mosaic rule. A list of catalog item visibilities gives the percentage contribution of the item to overall mosaic.

You can provide arguments to the identify operation as query parameters defined in the parameters table below.

Parameters

Parameter	Details
f	Description: The response format. The default response format is html. Values: html \| json
geometry	Required Description: A geometry that defines the location to be identified. The location can be a point or a polygon. The structure of the geometry is the same as the structure of the json geometry objects returned by the ArcGIS REST API. In addition to the JSON structures, for points, you can specify the geometry with a simpler comma-separated syntax. This is a `required` parameter. The default geometry type is a point. By default the geometry is assumed to be in the spatial reference of the image service. You can specify a different spatial reference, by using the JSON structure syntax for geometries. Syntax: JSON structures: `geometryType=<geometryType>&geometry={geometry}` Point simple syntax: `geometryType=esriGeometryPoint&geometry=<x>,<y>` Examples: `geometryType=esriGeometryPoint&geometry={x: -104, y: 35.6}` `geometryType=esriGeometryPoint&geometry=-104,35.6`
geometryType	Description: The type of geometry specified by the `geometry` parameter. The geometry type can be a point or polygon. Values: `esriGeometryPoint \| esriGeometryPolygon`
mosaicRule	Specifies the mosaic rule defining the image sorting order. `esriMosaicCenter`. Syntax: { "mosaicMethod" : "<esriMosaicNone \| esriMosaicCenter \| esriMosaicNadir \| esriMosaicViewpoint \| esriMosaicAttribute \| esriMosaicLockRaster \| esriMosaicNorthwest \| esriMosaicSeamline>", "where" : "<where>", "sortField" : "<sortFieldName>", "sortValue" : <sortValue>, "ascending" : <true \| false>, "lockRasterIds" : [<rasterId1>, <rasterId2>], "viewpoint" : <point>, "fids" : [<fid1>, <fid2>], "mosaicOperation" : "<MT_FIRST \| MT_LAST \| MT_MIN \| MT_MAX \| MT_MEAN \| MT_BLEND>" } Example: { "mosaicMethod" : "esriMosaicCenter", "sortField" : "Category", "ascending" : false }
renderingRule	//Added in 10.1 Specifies the rendering rule for how the requested image should be rendered. Syntax: { "rasterFunction" : "<rasterFunctionName>", "rasterFunctionArguments" : {<rasterFunctionArguments>}, //optional parameter. For information on default 'variableNames', check the Raster Functions documentation for details. "variableName" : "<variableName>" } The syntax of the `rasterFunctionArguments` property varies based on the specified `rasterFunction` name. Please refer to the Raster Functions documentation for more details.
pixelSize	Description: The pixel level being identified (or the resolution being looked at). If pixel size is not specified, then pixelSize will default to the base resolution of the dataset. The raster at the specified pixel size in the mosaic dataset will be used for identify. The structure of the `pixelSize` parameter is the same as the structure of the point object returned by the ArcGIS REST API. In addition to the JSON structure, you can specify the pixel size with a simpler comma-separated syntax. Syntax: JSON structure: `pixelSize={point}` Point simple syntax: `pixelSize=<x>,<y>` Examples: `pixelSize={x: 0.18, y: 0.18}` `pixelSize=0.18,0.18`
time	//Added in 10.1 Description: The time instant or the time extent of the raster to be identified. This parameter is only valid if the Image service supports time. Time instant Syntax: `time=<timeInstant>` Example: `time=1199145600000` (1 Jan 2008 00:00:00 GMT) Time extent (For time extents one of `<startTime>` or `<endTime>` could be `'null'`). Syntax: `time=<startTime>, <endTime>` Example: `time=1199145600000, 1230768000000` (1 Jan 2008 00:00:00 GMT to 1 Jan 2009 00:00:00 GMT) A null value specified for start time or end time will represent infinity for start or end time respectively.
returnGeometry	//Added in 10.1 Description: Indicates whether to return raster catalog item's footprint or not. Set it to false when catalog item's footprint is not needed to improve identify operation's response time. Syntax: `returnGeometry=<true \| false>` Example: `returnGeometry=false`
returnCatalogItems	//Added in 10.1 Description: Indicates whether to return raster catalog items or not. Set it to false when catalog items are not needed to improve identify operation's performance significantly. When set to false, both geometry and attributes of catalog items won't be returned. Syntax: `returnCatalogItems=<true \| false>` Example: `returnCatalogItems=false`

Example Usage

Example 1: Identify a single raster Image Service using a point geometry.

http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Earthquakes/SanAndreasLidar/ImageServer/identify?geometry={"x":575505.5,"y":3733770}&geometryType=esriGeometryPoint&mosaicRule=&pixelSize=0.5,0.5&f=pjson

Example 2: Identify a mosaic dataset Image Service using a polygon geometry and specify mosaic rule using esriMosaicAttribute method.

http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Portland/CascadeLandsat/ImageServer/identify?geometry={"rings": [[[-13555360.4191,5911556.581],[-13489311.5669, 5898227.932],[-13423477.4153,5884426.3329],[-13602646.9571, 5717848.4135], [-13587119.9125, 5781976.6214],[-13571360.1713, 5846543.2654],[-13555360.4191, 5911556.581]]]}&geometryType=esriGeometryPolygon
&mosaicRule={"mosaicMethod" : "esriMosaicAttribute","where" : "Name NOT LIKE 'Ov%'","sortField" : "Name","mosaicOperation" : "MT_MAX"}&f=html

Example 3: Identify a multi-source elevation service using a point geometry and not to return catalog items.

http://myserver:6080/arcgis/rest/services/elevation/ImageServer/identify?geometry={"x":575505.5,"y":3733770}&geometryType=esriGeometryPoint&mosaicRule=&pixelSize=0.5,0.5&returnCatalogItems=false&f=pjson

JSON Response Syntax

{
"objectId" : <objectId>,
"name" : "<name>",
"value" : "<pixelValue>",
"location" : <point>, //the identified location
"properties" : { //the properties (attributes) of the identified object. (returned only when the image service source is a mosaic dataset)
  "name1" : <value1>,
  "name2" : <value2>
},
//catalogItems are returned only when the image service source is a mosaic dataset.
"catalogItems" : {
  "objectIdFieldName" : "<objectIdFieldName>",
  "spatialReference" : <spatialReference>,
  "geometryType" : "<geometryType>",
  "features" : [ 
    <feature1>, <feature2>
  ]
},
//catalogItemVisibilities are returned only when the image service source is a mosaic dataset.
"catalogItemVisibilities" : [ <catalogItem1Visibility>, <catalogItem2Visibility> ]
}

JSON Response Example

{
"objectId" : 22,
"name" : "John Snow",
"value" : "0,1,2",
"location" : {x: -104, y: 35.6},
"properties" : {
   "Value: "10,22,33"
},
"catalogItems" : {
  "objectIdFieldName" : "IMAGEID",
  "spatialReference" : {"wkid" : 4326},
  "geometryType" : "esriGeometryPolygon",
  "features" : [
    {
      "geometry" : {
        "rings" : [ 
           [ [-97.06138,32.837], [-97.06133,32.836], [-97.06124,32.834], [-97.06127,32.832], [-97.06138,32.837] ]
        ]
      },
      "attributes" : {
        "IMAGEID" : 37,
        "OWNER" : "Joe Smith",
        "VALUE" : 94820.37,
        "APPROVED" : true,
        "LASTUPDATE" : 1227663551096
      }
    },
    {
      "geometry" : {
        "rings" : [ 
           [ [-97.06326,32.759], [-97.06298,32.755], [-97.06153,32.749], [-97.06326,32.759] ]
        ]
      },
      "attributes" : {
        "IMAGEID" : 462,
        "OWNER" : "John Doe",
        "VALUE" : 17325.90,
        "APPROVED" : false,
        "LASTUPDATE" : 1227628579430
      }
    }
  ]
},
"catalogItemVisibilities" : [ 0.7, 0.5 ]
}