Extracting an intersecting polygon from S123 Json response

568
1
09-13-2022 05:53 AM
AhmedShehata3
New Contributor III

Greetings, 

 

I'd like to use a Survey123 form to extract a polygon from a hosted feature layer that intersects with the location of the submitted survey. A scenario would be " Given a total number of 5 districts when a surveyor opens the survey in any of them (with a geo-point question capturing his location), the geometry of this district gets drawn in a following geo-shape question".   


I'm not a JS expert, but I edited the JS samples of the Survey123 connect templates and came up with the below code, but I can't get it to work. The JS function returns endless object (${element[1]} ${element[0]})

I understand that I'm not specific, but can anyone point out what is incorrect in the below code?

// Query a feature layer and returns the feature that intersects the location

function featureByLocation(layerURL, location, token) {

// Output value. Initially set to an empty string (XLSForm null)

let outValue = "";

let outRing = [];

// Check to make sure both layerURL and location are provided

if (layerURL == null || layerURL === "" || location == null || location === "") {

// The function can't go forward; exit with the empty value

return location;

}

 

// The coordinates will come in as `<lat> <lon> <alt> <acc>`.

// We need <lon>,<lat> for the query

// Note that I'm using the relatively new ` ` string that lets me place variables ${var}

let coordsArray = location.split(" ");

let coords = `${coordsArray[1]},${coordsArray[0]}`;

 

 

// Set up query parameters

let f = "f=json";

let returnGeometry = "returnGeometry=true";

let geometry = `geometry=${coords}`;

let geometryType = "geometryType=esriGeometryPoint";

let inSR = "inSR=4326";

let spatialRel = "spatialRel=esriSpatialRelIntersects";

let outFields = "outFields=*";

let returnCount = "returnCount=1";

let parameters = [f,returnGeometry, geometry,geometryType,inSR,spatialRel,outFields,,returnCount].join("&");

if (token) {

parameters = parameters + `&token=${token}`;

}

let url = `${layerURL}/query?${parameters}`;

 

// Create the request object

let xhr = new XMLHttpRequest();

// Make the request. Note the 3rd parameter, which makes this a synchronous request

xhr.open("GET", url, false);

xhr.send();

 

 

// Process the result

if (xhr.readyState === xhr.DONE) {

if (xhr.status !== 200) {

// The http request did not succeed

return "bad request: " + url

} else {

// Parse the response into an object

let response = JSON.parse(xhr.responseText);

if (response.error) {

// There was a problem with the query

} else {

if (response.features[0]) {

let ring = response["features"][0]["geometry"]["rings"][0];

ring.forEach(element => outRing.push('${element[1]} ${element[0]}'));

outValue = outRing.join(";");

} else {

// No features found

}

}

}

}

return outValue;

}

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1 Reply
chargeetudeti
New Contributor II

Hi Ahmed

do you find a solution ?

Thinks 

Julien

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