O V E R V I E W
A geometry service contains utility methods which provide access to sophisticated and frequently used geometric operations. An ArcGIS Server Web site can only expose one Geometry service with the static name "Geometry". Note that geometry input and output, where required, is always packaged as an array.
Use a geometry service to:
Buffer, densify, project, relate, and simplify geometry
Calculate areas, lengths, and label points for geometry
Edit and construct geometries (splitting polygons, constructing offset polylines, etc)
Return well known ids and text strings for spatial references and units
WSDL syntax
http://<Web Server Hostname>/<ArcGIS Instance>/services/Geometry/GeometryServer?wsdl
Working with a geometry service
Geometry service methods typically take as input a spatial reference (SR)
and an array of geometries assumed to be in that spatial SR. This
SR cannot be null. This allows callers to avoid
duplicating the spatial reference within each geometry in the array. The
geometry returned from a method call is not associated with a SR. It
is the consumers responsibility to associate the returned geometries with
the correct SR.
Finding a WellKnown ID
Working with a geometry service often involves defining a spatial reference,
transformation and/or unit. The International Association of Oil &
Gas Producers (OGP) maintains a set of internationally recognized numeric
codes to identify standard spatial references (coordinate systems), datum
transformations and linear and angular units of measure. The codes are
termed EPSG codes or "factory codes" from the European Petroleum
and Survey Group which was absorbed into the OGP. ESRI has also defined
a set of unique numeric codes to identify the same or similar geometric
entities. Other authorities and groups can define their own unique numeric
codes as well. In order to accommodate multiple
authorities without overlapping codes, the geometry service uses an explicitly
defined range of codes for known and unknown (custom) authorities. The
codes are designed to identify an commonly recognized geometric entity,
thus each code is termed a "wellknown id". Here
are the current rules for mapping WKID ranges to default authority names
used by a geometry service:
EPSG codes map to the WKID code range 1000  32768. EPSG version: 7.4.1
ESRI codes map to the WKID code range 33000  199999. Current ESRI PE (projection engine) library version: 10.0
Custom codes map to the WKID code range 200000  209199.
WKIDs for the EPSG and ESRI authorities are
available for the following entities:
Spatial Reference  Geographic Coordinate Systems
Type
Type3
Spatial Reference  Planar (Projected) Coordinate Systems
Type
Type4
Datum Transformations
Units
Type
Methods
Proxy method 
Description 

Constructs polygons that fill in the gaps between existing polygons and a set of polylines. 
Buffers an array of geometries by each distance specified in an array of distances.
 
Constructs the convex hull of the input geometries.
 
Splits input polylines or polygons where they cross a cutting polyline.
 
Converts nonlinear geometry to linear geometry.
Adds vertices to linear geometry.  
Connects input vertices with densified approximations to geodesic paths between them.
 
Constructs the settheoretic difference between an array of geometries and another geometry.
 
Defines a spatial reference based upon its well known identifier (WKID) and optionally a WKID for a vertical datum.
 
Defines a spatial reference based upon its well known text string (WKT) and optionally a WKT for a vertical datum.
 
Finds a predefined linear or angular unit of measure based on its EPSG or ESRI WKID.
 
Finds a predefined linear or angular unit of measure based on its EPSG definition string.
 
Applies DouglasPoiker generalization to the input polylines and polygons.
 
Calculates area and perimeter length for each polygon.
 
Calculates area and perimeter length for each polygon, allowing specification of output units.
 
Reports the shortest distance between two geometries.
 
Reports the shortest geodesic distance between two geometries.
 
Calculates points for label placement inside each input polygon.
 
Calculates length for each input polyline.
 
Calculates length for each input polyline, allows specification of output units.
 
Calculates the geodesic length for each input polyline, allowing for specification of output units.
 
Constructs the set theoretic intersection of each input and another geometry.
 
Constructs offset copies of the input polylines or polygons.
 
Projects an array of geometries from their current spatial reference to a destination spatial reference.
 
Determines the pairs of geometries from the input geometry arrays that participate in the specified spatial relation.
 
Reshapes a polyline or polygon using a reshaping line.
 
Generates topologically correct geometry.
 
Trims or extends each input polyline to meet another polyline.
 
Constructs the settheoretic union of the inputs.
