34:["$","title",null,{"children":"Converting from xy coordinates on a flat surface to geodetic coordinates | lindacmsheard | Observable"}] 3c:T445,md`### Initial approach To convert an xy point on our plane to latitude and longitude coordinates, we will need to perform the following steps: 1. Rotate our coordinate system to convert our distances traveled in y or x direction into distances traveled in a North or East direction, relative to our origin. 2. Achieve the scaling of meters to degrees of latitude and longitude, bearing in mind that this scaling is dependent on latitude on the globe. 3. Add the values to the latitude and longitude of our point of origin (The known location of our point [0,0]) While 1 and 3 are straightforward, there are a number of more and less accurate ways to achieve step 2. Chris Veness of [Movable-Type.co.uk](https://movable-type.co.uk/scripts/latlong-os-gridref.html) has done a thorough job of explaining and implementing one of the methods applied by the Ordnance Survey - essentially a reverse Mercator projection from the National Grid (OSGB36) to WGS84 geodetic coordinates. Since we are only interested in a small area, we'll keep it a little simpler for now and see how it goes! ` 3d:Tae8,html``3e:T4dc,function getLatLong(flatearth_pos, lat_long_origin, rotation, href) { // ellipsoid planet defined by flattening (WGS84). //var f = 1/298.257223563; // planetary equatorial radius (WGS84) //var Re = 6378137; var psi = Math.radians(rotation) var x = flatearth_pos[0] var y = flatearth_pos[1] var z = flatearth_pos[2] //var mu0 = Math.radians(lat_long_origin[0]) //var m_per_deg_lat = 111132.92 - 559.82 * Math.cos(2*mu0) + 1.175 * Math.cos(4*mu0) -0.0023 * Math.cos(6*mu0) //var m_per_deg_long = 111412.84 * Math.cos(mu0) -93.5* Math.cos(3*mu0) + 0.118 * Math.cos(5*mu0) //rotate //begin by transforming the flat Earth x and y coordinates to North and East coordinates, through a simple rotation. // (These will still be in meters.) var N = Math.cos(psi) * y - Math.sin(psi) * x // sin(psi) * 0 + cos(psi) * 200 var E = Math.sin(psi) * y + Math.cos(psi) * x var Ndeg = N / m_per_deg_lat var Edeg = E / m_per_deg_long //translate var lat = lat_long_origin[0] + Ndeg var long = lat_long_origin[1] + Edeg var alt = href + z //return [[lat,long, alt],[lat0,long0],[x,y,z],[N,E],[m_per_deg_lat,m_per_deg_long],[Ndeg,Edeg]] return [lat,long,alt] }3f:T706,function show(data) { replay; const svg = d3.select(DOM.svg(width, height)); const l = length(line(data)); svg.append("g") .call(xAxis); svg.append("g") .call(yAxis); svg.append("path") .datum(data) .attr("fill", "none") .attr("stroke", "black") .attr("stroke-width", 2.5) .attr("stroke-linejoin", "round") .attr("stroke-linecap", "round") .attr("stroke-dasharray", `0,${l}`) .attr("d", line) .transition() .duration(5000) .ease(d3.easeLinear) .attr("stroke-dasharray", `${l},${l}`); svg.append("g") .attr("fill", "white") .attr("stroke", "black") .attr("stroke-width", 2) .selectAll("circle") .data(data) .join("circle") .attr("cx", d => x(d.x)) .attr("cy", d => y(d.y)) .attr("r", 3); const label = svg.append("g") .attr("font-family", "sans-serif") .attr("font-size", 10) .selectAll("g") .data(data) .join("g") .attr("transform", d => `translate(${x(d.x)},${y(d.y)})`) .attr("opacity", 0); label.append("text") .text(d => d.name) .each(function(d) { const t = d3.select(this); switch (d.orient) { case "top": t.attr("text-anchor", "middle").attr("dy", "-0.7em"); break; case "right": t.attr("dx", "0.5em").attr("dy", "0.32em").attr("text-anchor", "start"); break; case "bottom": t.attr("text-anchor", "middle").attr("dy", "1.4em"); break; case "left": t.attr("dx", "-0.5em").attr("dy", "0.32em").attr("text-anchor", "end"); break; } }) .call(halo); label.transition() .delay((d, i) => length(line(data.slice(0, i + 1))) / l * (5000 - 125)) .attr("opacity", 1); return svg.node(); }40:T65a,// yes, I know, this is ugly. I need to get down with the d3 maths ... function showillustration() { var height = width/3 const context = DOM.context2d(width,height); const projection = d3.geoOrthographic().fitExtent([[10,10],[width - 100, height - 10]], {type:"Sphere"}); const path = d3.geoPath(projection, context); // sphere context.clearRect(0,0,width,height); context.beginPath(), path({type:"Sphere"}), context.strokeStyle = "#000", context.lineWidth = 1.5, context.stroke(); context.beginPath(), path(d3.geoGraticule10()), context.strokeStyle = "#000", context.lineWidth = 0.5, context.stroke(); // plane context.fillStyle = "rgba(230,255,220,0.75)"; context.beginPath(); context.moveTo(width/2-30, 15); context.lineTo(width/2+50, 35); context.lineTo(width/2+95, 120); context.lineTo(width/2-50, 105); context.closePath(); context.strokeStyle = "#000", context.lineWidth = 2, context.stroke(); context.fill(); // planar axes context.beginPath(); context.moveTo(width/2+12,35); context.lineTo(width/2+22,100); context.moveTo(width/2-25,60); context.lineTo(width/2+60,73); context.strokeStyle = "green", context.lineWidth = 2, context.stroke(); context.beginPath(); context.moveTo(width/2+16,65); context.lineTo(width/2-7,30); context.strokeStyle = "red", context.lineWidth = 2, context.stroke(); // labels context.fillStyle = "green"; context.font="14px arial"; context.fillText("y",width/2+17,42); context.fillText("x",width/2+50,83); context.fillStyle = "red"; context.fillText("N",width/2-20,40); return context.canvas; }41:[{"id":"343130ad03739bdc8231a8dc8b0df37ea601694d96105bfcee5e5a81a9350f6042ffce2834a4f2a0944eb826c7871aa903433fed4073046ea7a4b531b8c02c48","href":"https://static.observableusercontent.com/files/343130ad03739bdc8231a8dc8b0df37ea601694d96105bfcee5e5a81a9350f6042ffce2834a4f2a0944eb826c7871aa903433fed4073046ea7a4b531b8c02c48","name":"LLAtrackOnAzure.PNG","type":"image/png","lastModified":1581986222265.077,"size":368169},{"id":"0f940c594344a6ee1e335dd4eb62cc6a25f32fbc4bba03e5613e06e1083e03ecd4ff88fecdc6f1fae959b4f56ebf850b260ca860cd99ae4641f3f67bacdd40ae","href":"https://static.observableusercontent.com/files/0f940c594344a6ee1e335dd4eb62cc6a25f32fbc4bba03e5613e06e1083e03ecd4ff88fecdc6f1fae959b4f56ebf850b260ca860cd99ae4641f3f67bacdd40ae","name":"testdistanceazure.png","type":"image/png","lastModified":1581785992898.562,"size":84112},{"id":"028bc44de4952c9c8f83594e41151c6bf06e30388bc7a29e3520485ba72c39f115bc78b11dbfbdca26719ae72db77bf37e399e3e9225500d96c52c58bc939c11","href":"https://static.observableusercontent.com/files/028bc44de4952c9c8f83594e41151c6bf06e30388bc7a29e3520485ba72c39f115bc78b11dbfbdca26719ae72db77bf37e399e3e9225500d96c52c58bc939c11","name":"16022020-vupbunm3.csv","type":"text/csv","lastModified":1581897158954.915,"size":3577}] 38:{"id":"e571701c04d605f6","slug":"converting-from-xy-coordinates-on-a-flat-surface-to-geodeti","title":"Converting from xy coordinates on a flat surface to geodetic coordinates","thumbnail":"ef497c274a77a80c83e5558ac6cba8901759ed14284c7254e2dc7811049562a5","access_level":"public","create_time":"$D2020-02-15T15:24:31.963Z","update_time":"$D2020-02-18T13:34:39.507Z","view_time":null,"first_public_time":"$D2020-02-18T00:53:17.354Z","has_unpublished_edits":null,"fork":false,"stars":4,"starred":false,"owner":{"type":"team","id":"652d21c1e0895a5a","login":"lindacmsheard","name":"","avatar_url":"https://avatars-next.observableusercontent.com/c8b30f1715b661e3386c8c115a44c449606d105c0322fcbfb6e30248870f1c20","tier":"starter_2024","bio":"","followed_by_you":false,"follows_you":false},"version":1330,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"e6cfba4fdfcd2507","login":"lindacmsheard","name":"","avatar_url":"https://avatars-next.observableusercontent.com/c8b30f1715b661e3386c8c115a44c449606d105c0322fcbfb6e30248870f1c20","tier":null,"bio":"","followed_by_you":false,"follows_you":false}],"members":[{"type":"individual","id":"e6cfba4fdfcd2507","login":"lindacmsheard","name":"","avatar_url":"https://avatars-next.observableusercontent.com/c8b30f1715b661e3386c8c115a44c449606d105c0322fcbfb6e30248870f1c20","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":3,"collection":null,"type":"notebook","body":{"titling":"auto","title":"Converting from xy coordinates on a flat surface to geodetic coordinates","cells":[{"id":0,"value":"md`# Converting from xy coordinates on a flat surface to geodetic coordinates\n\n*Note: \"xy\" here does not refer to [ECEF cartesian coordinates](https://en.wikipedia.org/wiki/ECEF), where the xyz origin is at the center of the earth's core.*\n\n### The Goal\nThis exercise is about converting XY coordiates on a planar surface that touches the earth's surface tangentially at a single (custom) location, or origin.\n\nThe axes of the plane may be rotated with respect to north, as illustrated here:`\n","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":979,"value":"showillustration()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":966,"value":"md`### Some approximations\n\nIf the plane has a small extent relative to the size of the earth - say, of the order of the Silverstone Racecourse in the UK - then actual distances travelled and marked on the plane (in any direction, in meters) should be a sufficiently accurate indicator of position for our purposes. \n\nThis is because a small square-meter-grid plane approximates a [Mercator projection](https://en.wikipedia.org/wiki/Mercator_projection) with a custom line of tangency through our origin. Mercator projections are characterised by high accuracy near their line of tangency, and preserve the angles and the shapes of small objects.\n\nIncidentally, the Ordnance Survey's National Grid system for the UK (OSGB36) is such a system of plane coordinates, derived from a transverse mercator projection. \n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1000,"value":"$3c","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":35,"value":"md`---\n### Creating some test data\n\nBut first, let's create some useful test data.\n\nLet's assume that our xy plane is touching the earth's surface tangentially on the starting grid of the Silverstone Grand Prix circuit.\n\nUsing [www.freemaptools.com](https://www.freemaptools.com), we determine our [0,0] in xy coordinates as being located at latitude and longitude coordinates **52.06961232, -1.021817922**.\n\nFreemaptools can also tell us that this point lies at **147 m** above sea level.\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":36,"value":"start = [52.06961232,-1.021817922]\t","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":321,"value":"href = 147","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":39,"value":"md`Lets pick another point, exactly 200 m away, towards Abbey corner.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":47,"value":"abbey = [52.07103903,-1.020036936]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":63,"value":"md`Our test track now looks like this (visualised with [Azure Maps](https://azuremapscodesamples.azurewebsites.net/)):\n\n

${Object.assign(await FileAttachment(\"testdistanceazure.png\").image(), { alt: 'Silverstone', style: 'width: 100%; max-width: 400px;' })}\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":52,"value":"md`Now, let's align the y-axis of our flat plane to that straight, meaning that in our xy coordinate system, that 200m journey would go from [0,0] to [0,200]. \n\nWhilst we could calculate the rotation of our plane axes relative to north ourselves by working out the bearing between the start and end coordinates (see for example [here](https://www.igismap.com/formula-to-find-bearing-or-heading-angle-between-two-points-latitude-longitude/)), we can also just cheat and get it from a tool like [this one](http://instantglobe.com/CRANES/GeoCoordTool.html): \n\nOur y-axis deviates from north by 37.4995 degrees - we'll need this in our calculation later.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":636,"value":"bearing = 37.49949875876706","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":317,"value":"rotation = bearing","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":87,"value":"$3d","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1027,"value":"md`---\n### Calculate scaling factors based on latitude at origin\n\nSince we're not going very far from our origin, we will use constant scaling factors for all points, based on the latitude at the origin.\n\nSource of constants: [https://en.wikipedia.org/wiki/Geographic_coordinate_system](https://en.wikipedia.org/wiki/Geographic_coordinate_system)\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":775,"value":"mu0 = Math.radians(start[0])","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":771,"value":"m_per_deg_lat = 111132.92 - 559.82 * Math.cos(2*mu0) + 1.175 * Math.cos(4*mu0) -0.0023 * Math.cos(6*mu0)\n","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":772,"value":"m_per_deg_long = 111412.84 * Math.cos(mu0) -93.5* Math.cos(3*mu0) + 0.118 * Math.cos(5*mu0)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1020,"value":"md`---\n### Conversion function: XYZ to Lat / Long / Altitude\n\n\n\nSource for coordinate rotation: [https://www.mathworks.com/help/aerotbx/ug/flat2lla.html](https://www.mathworks.com/help/aerotbx/ug/flat2lla.html)`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1319,"value":"md`---\n \n| parameter | description |\n|----|----|\n|**flatearth_pos** | Flat earth position coordinates in meters|\n|**lat_long_origin** | Reference location, in degrees of latitude and longitude, for the origin of the flat Earth coordinate system. |\n|**rotation** |Angular direction of flat Earth x-axis (degrees clockwise from north), which is the angle in degrees used for converting flat Earth x and y coordinates to North and East coordinates.|\n|**href**|Reference height from the surface of the Earth to the flat Earth frame with regard to the flat Earth frame, in meters.|\n\n---`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":281,"value":"$3e","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":859,"value":"md`---\n### Conversion function: Lat / Long / Altitude to XYZ\n... and here is the reverse calculation:`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":864,"value":"function getXYZfromLLA(LLA, lat_long_origin, rotation, href) {\n var Ndeg = LLA[0] - lat_long_origin[0]\n var Edeg = LLA[1] - lat_long_origin[1]\n var psi = Math.radians(-rotation)\n \n // calculate meter coordinates\n var N = Ndeg * m_per_deg_lat\n var E = Edeg * m_per_deg_long\n \n //rotate:\n var y = Math.cos(psi) * N - Math.sin(psi) * E\n var x = Math.sin(psi) * N + Math.cos(psi) * E\n \n var z = LLA[2] - href\n \n return [x,y,z]\n\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":868,"value":"md`---\n### Single-point tests\nTest the conversion with a single point:`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":873,"value":"testXYZ = [50,200,10]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":286,"value":"LLresult = getLatLong([50,200,10], start, rotation, href)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1050,"value":"singlepointtestdata = [{category:\"start\",x:start[1],y:start[0]},\n {category:\"finish\",x:abbey[1],y:abbey[0]},\n {category:\"calculated\",x:LLresult[1],y:LLresult[0]}\n ]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":872,"value":"md`Test the reverse conversion with the result:`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":629,"value":"testLLA = [LLresult[0],LLresult[1],LLresult[2]]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":811,"value":"XYresult = getXYZfromLLA(testLLA,start,rotation, href)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":897,"value":"{\n var diff = [(testXYZ[0] - Math.round(XYresult[0],0)),(testXYZ[1] - Math.round(XYresult[1],0))]\n if (diff[0]+diff[1] == 0) {\n return \"Succeess: negligible difference after double conversion.\"\n }\n else {\n return diff\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":914,"value":"md`---\n### Load some track data (Lat Long)\n\nNote: this was created with clicks along the Silverstone track on [freemaptools.com](https://www.freemaptools.com).`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":838,"value":"track = Object.assign(d3.csvParse(await FileAttachment(\"16022020-vupbunm3.csv\").text(), ({Latitude: lat, Longitude: long}) => ({category:\"track\", x: long, y: lat})), {x: \"Longitude (degrees) →\", y: \"↑ Latitude (degrees)\"})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":960,"value":"md`#### Convert the track data to to XYZ coordinates`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1062,"value":"trackXYZ = track.map(function(d) {\n var LLA = [d.y,d.x,147];\n var point = getXYZfromLLA(LLA,start,rotation,href);\n return point;\n })","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1169,"value":"md`---\n#### Prepare for plotting the XYZ data\n\n*Note: This is the point where we could also load some racing game data if it's in meters on a planar surface.*`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1126,"value":"XYdata = {\n const data = trackXYZ.map(function (point) {\n var obj = {\n category:\"Track\",\n x : point[0],\n y : point[1]\n }\n return obj \n })\n data.x = \"x (m)\"\n data.y = \"y (m)\"\n return data\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1131,"value":"viewof replay = html`