topic Re: How can I Calculate a field in a hosted feature class using Rest API? in ArcGIS Online Questions

How can I Calculate a field in a hosted feature class using Rest API?

AllanLambert — Mon, 27 Jun 2016 15:54:56 GMT

I have a Damage Assessment feature layer hosted on AGOL with a web map. 50k points. Along with Domain controlled fields are Estimated % of Damage, Estimated $ Amt of Damage and a prepopulated Dwelling Value field. Field type is Double on these 3 fields. I need to either

1. Calc (Est $ Damage = DwellingVal * Est % Damage) on the fly as the user enters data for each point.

2. Create a URL to Calc (Est $ Damage = DwellingVal * Est % Damage) where (Est % Damage is >0). AGOL times out calc-ing the 50k records so I think the Where clause is necessary to only capture the 500 or 5000 that are damaged.

3. I'm open to ANY suggestion! Thanks. Allan

I can't get the REST API grid to work. The error says that the calcexpression is invalid:

Where: PercentDamage > 0

"calcExpression":[{"field" : "EstDollarDamage", "sqlExpression" : "DwellingVal*PercentDamage*.01"}]

http://services5.arcgis.com/cA4ofagPaJJ7qhEz/arcgis/rest/services/DamageAssessment_O_only/FeatureServer/0/calculate(where=”PercentDamage > 10 2”,calcExpression={“field”: “EstDollarDamage”,“sqlexpression” : "DwellingVal*PercentDamage*.01"})

Re: How can I Calculate a field in a hosted feature class using Rest API?

joerodmey — Thu, 16 Jan 2020 18:55:23 GMT

Did you ever get this figured out? I have the same question.

Re: How can I Calculate a field in a hosted feature class using Rest API?

AllanLambert — Thu, 16 Jan 2020 19:42:51 GMT

I called Tech Support a couple months later and luckily talked to the most helpful guy who wrote this py script in a couple hours. I don't think ESRI "gives" this kind of help anymore. I can't put my hands on the token documentation. I put this script in a sched task and it runs every 5 mins during storm damage assessment. Good Luck. Allan

import urllib
import urllib2
import httplib
import json

##Token Generation Parameters
tokenUrl = 'https://www.arcgis.com/sharing/oauth2/token'
featureServiceURL = 'https://services5.arcgis.com/xxxxxxxxx/arcgis/rest/services/MyDamageAssessmentService2019/FeatureServer/0/calculate'
clientId = 'xxxxxxxxxxxx'
clientSecret = 'xxxxxxxxxxxxxxxxxxx'

##Calculate Parameters - Only calc if a property has been assessed PercentDam > 0
whereClause = 'PercentDam > 0'
updateExpression = [{"field":"EstDollarD","sqlExpression":"Dwlgval1*PercentDam*.01"}]

def sendRequest(url, parameters):
data = urllib.urlencode(parameters)
req = urllib2.Request(url, data)
response = urllib2.urlopen(req)
return json.loads(response.read())

def generateToken():
tokenParameters = {'client_id': clientId, 'client_secret': clientSecret, 'grant_type':'client_credentials'}
jsonResponse = sendRequest(tokenUrl, tokenParameters)
token = jsonResponse["access_token"]
return token

def calculateValues(token):
calculateParameters = {'where':whereClause,'calcExpression':updateExpression,'sqlFormat':'standard','rollbackOnArithmaticError':'false','token':token, 'f':'json'}
jsonResponse = sendRequest(featureServiceURL, calculateParameters)
if jsonResponse['success'] == True:
  print "Updated Feature Count: " + str(jsonResponse["updatedFeatureCount"])
else:
  print "Calculate operation failed"
  print jsonResponse

token = generateToken()
calculateValues(token)