Send Geometry to query using ArcGIS REST API

Question

I am writing a windows console app in VS 2010 to perform an overlay using the ArcGIS Rest API.

My first REST query returns information about the geometry for a specific feature. I then want to send that geometry to another feature class, to return data about the shared area.

I am using the DeserializeObject method to convert the query results to a Dictionary. How do I take the geometry from that result set and post it to a new query?

Update:

What if I user the JavaScriptSerializer.Serialize method on the geometry string? Is there a way to pass the resulting JSON string to the REST service call? I already tried just assigning it to the "geometry" value in the querystring, but that failed.

• Kirk Kuykendall: "send that to another feature class" ... is that local or through another REST call?
• Britt Wescott: Another REST call
• Kirk Kuykendall: Would dependencies on Esri's WPF SDK assemblies be acceptable?
• Britt Wescott: I've considered that, I wanted to see if there was a way to do it just with REST calls before I opted for that route.
• Kirk Kuykendall: Have you tried Vish's GeoJson.NET ?

Answer 1

The code below works for me.

using System;
using System.Text;
using System.Net;
using Newtonsoft.Json;
using System.IO;
using Newtonsoft.Json.Linq;
namespace ConsoleApplication1
{
 class Program
 {
 static void Main(string[] args)
 {
 try
 {
 string baseUrl = @"http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer";
 string jsonGeom = GetStateGeom(baseUrl,1, "Colorado");
 string featuresJson = QueryHighways(baseUrl, 0, jsonGeom);
 Console.WriteLine(featuresJson);
 }
 catch (Exception ex)
 {
 Console.WriteLine(ex.Message);
 }
 Console.ReadLine();
 }
 private static string GetStateGeom(string baseUrl, int layerID,string state)
 {
 string url = String.Format("{0}/{1}/query?text={2}&f=pjson",baseUrl,layerID,state);
 var wc = new WebClient();
 var strm = wc.OpenRead(new Uri(url));
 var strmReader = new StreamReader(strm);
 var json = strmReader.ReadToEnd();
 //Console.WriteLine(json);
 strm.Close();
 var jObj = JsonConvert.DeserializeObject(json) as JObject;
 JArray features = (JArray)jObj["features"];
 if (features.Count == 0)
 {
 Console.WriteLine("state of {0} not found", state);
 return null;
 }
 string jsonGeom = ((JObject)features[0])["geometry"].ToString();
 return jsonGeom;
 }
 private static string QueryHighways(string baseUrl, int layerID,string jsonGeom)
 {
 string url = String.Format("{0}/{1}/query", baseUrl, layerID);
 var wc = new WebClient();
 wc.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
 StringBuilder sb = new StringBuilder();
 sb.Append("geometryType=esriGeometryPolygon");
 sb.Append(String.Format("&geometry={0}",jsonGeom));
 sb.Append("&inSR=&spatialRel=esriSpatialRelIntersects");
 sb.Append("&returnGeometry=true");
 sb.Append("&relationParam=");
 sb.Append("&where=");
 sb.Append("&returnCountOnly=false");
 sb.Append("&maxAllowableOffset=");
 sb.Append("&f=pjson");
 var bytes = Encoding.ASCII.GetBytes(sb.ToString());
 var respBytes = wc.UploadData(url, "POST", bytes);
 return Encoding.ASCII.GetString(respBytes);
 }
 }
}

Answer 2

There is some JSON helpers i ArcObjects that you might be able to use, but I'm not sure if they are supported on the client side though: SOESupport.JsonObject