42:null 43:["$","title",null,{"children":"Smashed SEG-Y Reader | Colin Howard | Observable"}] 49:T1edc,function translate(input){ var x = 0; var raw = input; var cooked = ""; var str; var ebcdic = "" for (x = 0; x <= (raw.byteLength-1); x+=1){ str=("00"+raw.getUint8(x).toString(16)).substr(-2); var hex1 = str.substring(0, 1); var hex2 = str.substring(1, 2); if ((hex1 >= 'a') && (hex1 <= 'f')){ hex1 = hex1.toUpperCase(); } if ((hex2 >= 'a') && (hex2 <= 'f')){ hex2 = hex2.toUpperCase(); } if (((hex1 >= 'A' && hex1 <= 'F') || (hex1 >= '0' && hex1 <='9')) && ((hex2 >= 'A' && hex2 <= 'F') || (hex2 >= '0' && hex2 <='9'))) { var hexbyte = hex1 + hex2; ebcdic = '.'; // Quite the brute force method here switch(hexbyte) { case '00': ebcdic = ''; break; case '01': ebcdic = ''; break; case '02': ebcdic = ''; break; case '03': ebcdic = ''; break; case '04': ebcdic = ''; break; case '05': ebcdic = '' ; break; case '06': ebcdic = ''; break; case '07': ebcdic = ''; break; case '08': ebcdic = '' ; break; case '09': ebcdic = ''; break; case '0A': ebcdic = ''; break; case '0B': ebcdic = '' ; break; case '0C': ebcdic = '' ; break; case '0D': ebcdic = '\n' ; break; case '0E': ebcdic = '' ; break; case '0F': ebcdic = '' ; break; case '10': ebcdic = ''; break; case '11': ebcdic = ''; break; case '12': ebcdic = ''; break; case '13': ebcdic = ''; break; case '14': ebcdic = ''; break; case '15': ebcdic = '' ; break; case '16': ebcdic = '' ; break; case '17': ebcdic = ''; break; case '18': ebcdic = ''; break; case '19': ebcdic = '' ; break; case '1A': ebcdic = ''; break; case '1B': ebcdic = ''; break; case '1C': ebcdic = ''; break; case '1D': ebcdic = '' ; break; case '1E': ebcdic = ''; break; case '1F': ebcdic = ''; break; case '20': ebcdic = '' ; break; case '21': ebcdic = ''; break; case '22': ebcdic = '' ; break; case '23': ebcdic = ''; break; case '24': ebcdic = ''; break; case '25': ebcdic = '' ; break; case '26': ebcdic = ''; break; case '27': ebcdic = ''; break; case '28': ebcdic = '' ; break; case '29': ebcdic = ''; break; case '2A': ebcdic = ''; break; case '2B': ebcdic = ''; break; case '2C': ebcdic = ''; break; case '2D': ebcdic = ''; break; case '2E': ebcdic = ''; break; case '2F': ebcdic = ''; break; case '30': break; case '31': break; case '32': ebcdic = ''; break; case '33': ebcdic = '' ; break; case '34': ebcdic = '' ; break; case '35': ebcdic = ''; break; case '36': ebcdic = ''; break; case '37': ebcdic = ''; break; case '38': ebcdic = ''; break; case '39': ebcdic = '' ; break; case '3A': ebcdic = ''; break; case '3B': ebcdic = ''; break; case '3C': ebcdic = ''; break; case '3D': ebcdic = ''; break; case '3E': break; case '3F': ebcdic = '_{'; break;
case '40': ebcdic = ' ' ; break;
case '41': ebcdic = ''; break;
case '42': break;
case '43': break;
case '44': break;
case '45': break;
case '46': break;
case '47': break;
case '48': break;
case '49': break;
case '4A': ebcdic = '['; break;
case '4B': ebcdic = '.'; break;
case '4C': ebcdic = '<'; break;
case '4D': ebcdic = '('; break;
case '4E': ebcdic = '+'; break;
case '4F': ebcdic = '|'; break;
case '50': ebcdic = '&'; break;
case '51': break;
case '52': break;
case '53': break;
case '54': break;
case '55': break;
case '56': break;
case '57': break;
case '58': break;
case '59': break;
case '5A': ebcdic = '!'; break;
case '5B': ebcdic = '$'; break;
case '5C': ebcdic = '*'; break;
case '5D': ebcdic = ')'; break;
case '5E': ebcdic = ';'; break;
case '5F': ebcdic = '^'; break;
case '60': ebcdic = '_'; break;
case '61': ebcdic = '/'; break;
case '62': break;
case '63': break;
case '64': break;
case '65': break;
case '66': break;
case '67': break;
case '68': break;
case '69': break;
case '6A': ebcdic = '|'; break;
case '6B': ebcdic = ','; break;
case '6C': ebcdic = '%'; break;
case '6D': ebcdic = '_'; break;
case '6E': ebcdic = '>'; break;
case '6F': ebcdic = '?'; break;
case '70': break;
case '71': break;
case '72': break;
case '73': break;
case '74': break;
case '75': break;
case '76': break;
case '77': break;
case '78': break;
case '79': ebcdic = '`'; break;
case '7A': ebcdic = ':'; break;
case '7B': ebcdic = '#'; break;
case '7C': ebcdic = '@'; break;
case '7D': ebcdic = "'"; break;
case '7E': ebcdic = '='; break;
case '7F': ebcdic = '"'; break;
case '80': break;
case '81': ebcdic = 'a'; break;
case '82': ebcdic = 'b'; break;
case '83': ebcdic = 'c'; break;
case '84': ebcdic = 'd'; break;
case '85': ebcdic = 'e'; break;
case '86': ebcdic = 'f'; break;
case '87': ebcdic = 'g'; break;
case '88': ebcdic = 'h'; break;
case '89': ebcdic = 'i'; break;
case '8A': break;
case '8B': ebcdic = '{'; break;
case '8C': break;
case '8D': break;
case '8E': break;
case '8F': ebcdic = '+'; break;
case '90': break;
case '91': ebcdic = 'j'; break;
case '92': ebcdic = 'k'; break;
case '93': ebcdic = 'l'; break;
case '94': ebcdic = 'm'; break;
case '95': ebcdic = 'n'; break;
case '96': ebcdic = 'o'; break;
case '97': ebcdic = 'p'; break;
case '98': ebcdic = 'q'; break;
case '99': ebcdic = 'r'; break;
case '9A': break;
case '9B': ebcdic = '}'; break;
case '9C': break;
case '9D': break;
case '9E': break;
case '9F': break;
case 'A0': break;
case 'A1': ebcdic = '~'; break;
case 'A2': ebcdic = 's'; break;
case 'A3': ebcdic = 't'; break;
case 'A4': ebcdic = 'u'; break;
case 'A5': ebcdic = 'v'; break;
case 'A6': ebcdic = 'w'; break;
case 'A7': ebcdic = 'x'; break;
case 'A8': ebcdic = 'y'; break;
case 'A9': ebcdic = 'z'; break;
case 'AA': break;
case 'AB': break;
case 'AC': break;
case 'AD': ebcdic = '['; break;
case 'AE': break;
case 'AF': break;
case 'B0': break;
case 'B1': break;
case 'B2': break;
case 'B3': break;
case 'B4': break;
case 'B5': break;
case 'B6': break;
case 'B7': break;
case 'B8': break;
case 'B9': break;
case 'BA': break;
case 'BB': break;
case 'BC': break;
case 'BD': break;
case 'BE': break;
case 'BF': break;
case 'C0': ebcdic = '{'; break;
case 'C1': ebcdic = 'A'; break;
case 'C2': ebcdic = 'B'; break;
case 'C3': ebcdic = 'C'; break;
case 'C4': ebcdic = 'D'; break;
case 'C5': ebcdic = 'E'; break;
case 'C6': ebcdic = 'F'; break;
case 'C7': ebcdic = 'G'; break;
case 'C8': ebcdic = 'H'; break;
case 'C9': ebcdic = 'I'; break;
case 'CA': break;
case 'CB': break;
case 'CC': break;
case 'CD': break;
case 'CE': break;
case 'CF': break;
case 'D0': ebcdic = '}'; break;
case 'D1': ebcdic = 'J'; break;
case 'D2': ebcdic = 'K'; break;
case 'D3': ebcdic = 'L'; break;
case 'D4': ebcdic = 'M'; break;
case 'D5': ebcdic = 'N'; break;
case 'D6': ebcdic = 'O'; break;
case 'D7': ebcdic = 'P'; break;
case 'D8': ebcdic = 'Q'; break;
case 'D9': ebcdic = 'R'; break;
case 'DA': break;
case 'DB': break;
case 'DC': break;
case 'DD': break;
case 'DE': break;
case 'DF': break;
case 'E0': ebcdic = '\\'; break;
case 'E1': break;
case 'E2': ebcdic = 'S'; break;
case 'E3': ebcdic = 'T'; break;
case 'E4': ebcdic = 'U'; break;
case 'E5': ebcdic = 'V'; break;
case 'E6': ebcdic = 'W'; break;
case 'E7': ebcdic = 'X'; break;
case 'E8': ebcdic = 'Y'; break;
case 'E9': ebcdic = 'Z'; break;
case 'EA': break;
case 'EB': break;
case 'EC': break;
case 'ED': break;
case 'EE': break;
case 'EF': break;
case 'F0': ebcdic = '0'; break;
case 'F1': ebcdic = '1'; break;
case 'F2': ebcdic = '2'; break;
case 'F3': ebcdic = '3'; break;
case 'F4': ebcdic = '4'; break;
case 'F5': ebcdic = '5'; break;
case 'F6': ebcdic = '6'; break;
case 'F7': ebcdic = '7'; break;
case 'F8': ebcdic = '8'; break;
case 'F9': ebcdic = '9'; break;
case 'FA': break;
case 'FB': break;
case 'FC': break;
case 'FD': break;
case 'FE': break;
case 'FF': break;
default : ebcdic = '<>'; break;
}
//x = x + 1;
cooked = cooked + ebcdic;
}
else if (hex1 != ' ') {cooked = cooked + ''; }
}
return cooked;
}4a:T810,// Loop over file contents (in this case a bunch of files). Return address of start of next file or EOF
contents = {
let start = 0;
let done = false;
let record = {};
let all_records=[];
let files_done = 0;
do {
// start =
let record = {};
let traces = []; // trace data for each trace per record
// extract Text header
let txt_dataview = new DataView(what.slice(start,start+3200));
// extract info from binary header
record["EBCDIC"] = read_EBCDIC(txt_dataview);
let bhdr_dataview = new DataView(what.slice(start+3200,start+3200+400));
if (bhdr_dataview.byteLength == 0) break;
let Samps =bhdr_dataview.getInt16(20); //RELY ON THE BINARY HEADER NUM SAMPS VALUE
//Samps = 3300;
let tr_len = Samps*4 + 240; // should really read the data format to get sample format length
// loop over trace headers. TODO Come back to reading the data shortly.
let tr_count=0;
record["fileStart"] = start;
record["traceLen"] = tr_len;
for(let i= start+3200+400; i <= (what.byteLength); i=i+tr_len){
start = i;
if (i == what.byteLength) {break;}
let dv= new DataView(what.slice(i,i+240));
//Samps = dv.getInt16(114);
//if (dv.getInt16(0) > 1) break;
//if(dv.getInt16(114) != (Samps)) {break;} // checking whether we have gone into next trace or next file
if(i >= ALL_EBCDIC[files_done+1]) break;
tr_count++;
let tr_data = [];
let j=0;
// read the trace. For now assume it's IBM Float 32
let dv2 = new DataView(what.slice(i+240,i+240+Samps*4));
for (let n=i+240; n < i+(240+Samps*4); n=n+4){
//loop over samples
tr_data[j]=nfm(dv2,j*4);
j++;
}
traces.push(tr_data);

}
files_done++;
record["fileEnd"]= start;
record["numTraces"]= tr_count;
record["tr_data"] = traces;
tr_count = 0;
all_records.push(record);
if(start == (what.byteLength)) done=true; // TODO what if last trace is not complete?
} while (!done)

return all_records;
}4b:T414,function onFs(fs) {

fs.root.getFile('/temp/log.txt', {create: true}, function(fileEntry) {

// Create a FileWriter object for our FileEntry.
fileEntry.createWriter(function(fileWriter) {

fileWriter.onwrite = function(e) {
console.log('Write completed.');
};

fileWriter.onerror = function(e) {
console.log('Write failed: ' + e.toString());
};

//var bb = new BlobBuilder(); // Create a new Blob on-the-fly.
//bb.append('Lorem Ipsum');

//var dataView = new DataView(arrayBuffer);
//var bb = new Blob([dataView], { type: mimeString });

//var byteArray = new Uint8Array(hexdata.length/2);
//getFile();
var byteArray = new Uint8Array(what.slice(0,7000)) //.slice(448)
/* for (var x = 0; x < byteArray.length; x++){
byteArray[x] = parseInt(hexdata.substr(x*2,2), 16);
} */
var bb = new Blob([byteArray], {type: "application/octet-stream"});

fileWriter.write(bb.getBlob('text/plain'));

}, onError);

}, onError);

}4c:[]
47:{"id":"02a078af3fa4a98f","slug":null,"title":"Smashed SEG-Y Reader","thumbnail":"49e3b8e7b5c25c76853ac31b4ed41e895e2facb91573182f4e68e995d0ccb899","access_level":"public","create_time":"$D2023-03-24T14:07:33.101Z","update_time":"$D2025-12-04T16:57:23.165Z","view_time":null,"first_public_time":"$D2023-03-24T14:07:33.101Z","has_unpublished_edits":null,"fork":{"id":"f22612230f3d69a7","slug":"reading-local-files","title":"Reading Local Files","owner":{"id":"8c2e47252fd4995c","login":"mbostock","name":"Mike Bostock"}},"stars":0,"starred":false,"owner":{"type":"team","id":"5a1913bb9ff5c35c","login":"exit","name":"Colin Howard","avatar_url":"https://avatars-next.observableusercontent.com/7a42d351548eb4da28654d03297b77c4f1016e2d39abd6ee20dc3ec0e114bf88","tier":"starter_2024","bio":"","following":false},"version":683,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"4c678717b47212d8","login":"exit","name":"Colin Howard","avatar_url":"https://avatars-next.observableusercontent.com/7a42d351548eb4da28654d03297b77c4f1016e2d39abd6ee20dc3ec0e114bf88","tier":null,"bio":"","following":false}],"members":[{"type":"individual","id":"4c678717b47212d8","login":"exit","name":"Colin Howard","avatar_url":"https://avatars-next.observableusercontent.com/7a42d351548eb4da28654d03297b77c4f1016e2d39abd6ee20dc3ec0e114bf88","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":2,"collection":null,"type":"notebook","body":{"titling":"auto","title":"Smashed SEG-Y Reader","cells":[{"id":0,"value":"md`# Smashed SEG-Y Reader\n\n***Update Oct. 2021:*** *Observable now supports [**file inputs**](/@observablehq/input-file)! This notebook will remain for history, but please upgrade to [Observable Inputs](/@observablehq/inputs).*
\n\nAs an alternative to [attaching a file](https://observablehq.com/@observablehq/file-attachments) to your notebook, you can read files from your local file system in Observable using a file input:`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":3,"value":"viewof file = html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":81,"value":"md`The initial value of a file input is undefined, so any cell that references this file will wait for the reader to choose a file before running. If you’d an initial value so that referencing cells run on load, wrap the input in a form and assign the form’s value. Or, import my reusable [file input with initial value](/@mbostock/file-input-with-initial-value).`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":39,"value":"md`A [File](https://developer.mozilla.org/docs/Web/API/File) is a [Blob](https://developer.mozilla.org/docs/Web/API/Blob), so one way to read a file is to use [URL.createObjectURL](https://developer.mozilla.org/docs/Web/API/URL/createObjectURL). This is useful, for example, with images. (Don’t forget to [revoke](https://developer.mozilla.org/docs/Web/API/URL/revokeObjectURL) your URLs, though, say using [Generators.disposable](https://github.com/observablehq/notebook-stdlib/blob/master/README.md#Generators_disposable).)`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":47,"value":"html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":64,"value":"md`This works with [require](https://github.com/observablehq/stdlib/blob/master/README.md#require), too.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":69,"value":"viewof source = html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":71,"value":"module = require(URL.createObjectURL(source))","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":10,"value":"md`You can also read a file using a [FileReader](https://developer.mozilla.org/docs/Web/API/FileReader). Observable’s [standard library](https://github.com/observablehq/stdlib/blob/master/README.md) includes several convenience methods for reading files.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":11,"value":"Files","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":28,"value":"md`If the file is text, use Files.text to obtain a promise to a String.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":51,"value":"viewof text = html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":56,"value":"md`For a binary file, use Files.buffer for a promise to an ArrayBuffer.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":58,"value":"viewof binary = html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":491,"value":"binary.name.split(\".\")[0]","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":61,"value":"what_the = Files.buffer(binary)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":543,"value":"what = what_the.slice(788560) //.slice(0,3800)// what_the.slice(3967680)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":657,"value":"what1 = what_the.slice(7885600) //.slice(0,3800)// what_the.slice(3967680)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":99,"value":"uint8 = new Uint8Array(what_the) //.slice(448)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":116,"value":"uint8.map((i) => {let x=i; return x })// Number(x).toString(16).padStart(2, '0')})\n//(64).toString(16)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":136,"value":"solonly= [...new Uint8Array(uint8.slice(0,80))]\n .map (b => b.toString (16).padStart (2, \"0\"))\n .join (\" \")","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":144,"value":"what.byteLength","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":163,"value":"dataview = {\n const dataview = new DataView(what.slice(0,3200));\n //const dataview = new DataView(what.slice(21996880,21996880+3200));\n //dataview.setInt16(1, 42); // set type Int16 with value 42 in 1st byte\n //dataview.setInt8(3, 4); // set type Int8 with value 1 in 3rd byte\n \n return dataview\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":166,"value":"{\nvar str;\nvar raw = dataview;\nfor (let x = 0; x <= (raw.byteLength-1); x+=1){\nstr=(\"00\"+raw.getUint8(x).toString(16)).substr(-2);\n//var hex1 = str.substring(0, 1);\n//var hex2 = str.substring(1, 2);\n//return str;\n}\nreturn translate(dataview).match(/.{1,80}/g); //str;\n\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":150,"value":"function typefile(file) {\n var slice = file.slice(0,80); // Only read the start of the file\n var reader = new FileReader(); // Create an asynchronous FileReader\n var translated = \"\"\n reader.readAsArrayBuffer(slice); // Read the slice of the file\n reader.onload = function(e) {\n var buffer = reader.result; // The result ArrayBuffer\n var view = new DataView(buffer); // Get access to the result bytes\n //var magic = view.getUint8(0, false); // Read 4 bytes, big-endian\n //console.log((\"00\"+magic.toString(16)).substr(-2));\n console.log(file.name);\n var str=translate(view);\n var arr=str.match(/.{1,80}/g);\n //arr.map(function(d){console.log(d);});\n arr.map(function(d){translated.push(d);});\n };\n return translated;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":139,"value":"$49","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":204,"value":"dataview_bHDR = {\n const dataview = new DataView(what.slice(3200,3200+400));\n //const dataview = new DataView(what.slice(1043680+3200,1043680+3200+400));\n //dataview.setInt16(1, 42); // set type Int16 with value 42 in 1st byte\n //dataview.setInt8(3, 4); // set type Int8 with value 1 in 3rd byte\n \n return dataview\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":206,"value":"numSamps=dataview_bHDR.getInt16(20)\n\n/* var dv=new DataView(result);\n\n // Do something with first 400 byte binary header\n \n binHdr.format=dv.getInt16(24);\n binHdr.numSamps=dv.getInt16(20); \n binHdr.sampInterval=dv.getInt16(16); \n binHdr.traces=(result.byteLength-400)/(4*binHdr.numSamps+240); */","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":214,"value":"dataview_trHDR = {\n const dataview = new DataView(what.slice(3200+400,3200+400+240));\n //const dataview = new DataView(what.slice(1043680+3200+400,1043680+3200+400+240));\n //dataview.setInt16(1, 42); // set type Int16 with value 42 in 1st byte\n //dataview.setInt8(3, 4); // set type Int8 with value 1 in 3rd byte\n \n return dataview\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":216,"value":"trlen = { \n let TraceLen_b = 0;\n let TraceNumber = dataview_trHDR.getInt32(0);\n let numSamps_trHDR=dataview_trHDR.getInt16(114);\n let SampInterval = dataview_trHDR.getInt16(116);\n return TraceLen_b = numSamps_trHDR*4 +240;\n/*\n number of samples is in the trace header byte 115 (zero basis 114 of course) as a two byte value (Int16) and should be consistent with the binary header\n\n */\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":253,"value":"dataview_trHDR.getInt16(114);","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":523,"value":"numSamps_trHDR = dataview_trHDR.getInt16(114);","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":540,"value":"trlen","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":248,"value":"{for(let i= 3200+400; i < (what.byteLength); i=i+trlen){\n //{for(let i= 1043680+3200+400; i < (what.byteLength); i=i+trlen){\n let dv= new DataView(what.slice(i,i+240));\n if(dv.getInt16(114) != 3300) return i;\n}\n return \"EOF\"\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":265,"value":"$4a","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":334,"value":"(1095524352).toString (16).padStart (2, \"0\")","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":313,"value":"function read_EBCDIC(raw)\n{\n// raw is a dataview of the EBCDIC usually as 3200 bytes\n var str;\n//var raw = dataview;\nfor (let x = 0; x <= (raw.byteLength-1); x+=1){\nstr=(\"00\"+raw.getUint8(x).toString(16)).substr(-2);\n//var hex1 = str.substring(0, 1);\n//var hex2 = str.substring(1, 2);\nreturn translate(raw).match(/.{1,80}/g); //str;\n}\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":321,"value":"function IBM_to_IEEE(data_trace){\n \n var obuff=new ArrayBuffer(4); // Used for conversion of IBM32 float to IEEE float\n var a_float32= new Float32Array(obuff);\n var fr = new Uint32Array(obuff);\n\nif(binHdr.format == 5){\n nfm=function(offset,endian)\n {return dv.getFloat32(offset,endian);};\n }\n else if(binHdr.format == 1){\n nfm=function(offset,endian){\n // Convert a IBM32 32 Float to IEEE float\n fr[0] = dv.getUint32(offset);\n if(fr[0] != 0){\n sgn= fr[0] >>> 31;\n //alert(\"sign is\",sgn);\n fr[0] <<=1;\n exp = fr[0] >>> 25;\n //alert(\"exp is\",exp);\n fr[0] <<= 7;\n exp=(exp<<2)-130;\n \n while(fr[0] < 0x80000000){\n exp--;\n fr[0] <<=1;\n }\n \n fr[0] <<=1;\n\n fr[0]=(fr[0]>>>9)|(exp << 23)|(sgn <<31);\n }\n return a_float32[0];\n };\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":324,"value":"nfm=function(dv,offset,endian){\n var obuff=new ArrayBuffer(4); // Used for conversion of IBM32 float to IEEE float\n var a_float32= new Float32Array(obuff);\n var fr = new Uint32Array(obuff);\n // Convert a IBM32 32 Float to IEEE float\n // return dv.getUint32(offset); // debug\n fr[0] = dv.getUint32(offset);\n if(fr[0] != 0){\n let sgn= fr[0] >>> 31;\n //alert(\"sign is\",sgn);\n fr[0] <<=1;\n let exp = fr[0] >>> 25;\n //alert(\"exp is\",exp);\n fr[0] <<= 7;\n exp=(exp<<2)-130;\n \n while(fr[0] < 0x80000000){\n exp--;\n fr[0] <<=1;\n }\n \n fr[0] <<=1;\n\n fr[0]=(fr[0]>>>9)|(exp << 23)|(sgn <<31);\n }\n return a_float32[0];\n }","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":341,"value":"Plot.plot({\n marks: [\n Plot.image(\n d3.cross([0], [0, 1, 2, 3, 4]).map(([a,b]) => ({a,b})),\n {\n x: \"a\",\n y: \"b\",\n src: ({ a, b }) =>\n `data:image/svg+xml;utf8,${onePlot(a, b).outerHTML}`,\n width: 80,\n height: 40\n }\n )\n ],\n inset: 20,\n insetLeft: 30,\n width: 520,\n height: 260\n})","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":339,"value":"onePlot = (a, b) =>\n d3.select(Plot.plot({\n marks: [\n Plot.frame(),\n Plot.lineY(\n Array.from(\n { length: 100 },\n (_, i) => Math.sin((i * a) / 50) + Math.cos((i * b) / 10)\n )\n )\n ],\n inset: 4,\n width: 50,\n height: 80,\n margin: 2,\n x: {axis: null},\n y: {axis: null},\n })).attr(\"xmlns\", d3.namespaces.svg).node()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":355,"value":"pts = {\n return contents[0].tr_data[5].map((x,i) => [i, x]);\n //\n }","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":460,"value":"saveFile()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":351,"value":"Plot.plot({\n width: 1040,\n height: 200,\n y: { domain: [-100, 100] },\n //y: { domain: [0, 25] },\n //y: { domain: [-100, 2000] },\n marks: [\n Plot.line(\n // build_samples((x) => Math.exp(-x * x), -2.8, 2.8),\n pts,\n {\n strokeWidth: 3,\n stroke: \"steelblue\"\n }\n ),\n /* Plot.dot(\n [\n [1 / Math.sqrt(2), Math.exp(-1 / 2)],\n [-1 / Math.sqrt(2), Math.exp(-1 / 2)]\n ],\n { fill: \"black\", r: 5 }\n ), */\n Plot.ruleX([0]),\n Plot.ruleY([0])\n ]\n})","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":442,"value":"$4b","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":450,"value":"async function getFile() {\n // Open file picker and destructure the result the first handle\n const [fileHandle] = await window.showOpenFilePicker();\n const file = await fileHandle.getFile();\n return file;\n}// window.requestFileSystem(TEMPORARY, 1024*1024 /*1MB*/, onFs, onError)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":455,"value":"async function saveFile() {\n // create a new handle\n const newHandle = await window.showSaveFilePicker();\n\n // create a FileSystemWritableFileStream to write to\n const writableStream = await newHandle.createWritable();\n\n // write our file\n\n var byteArray = new Uint8Array(what.slice(0,7000)) //.slice(448)\n /* for (var x = 0; x < byteArray.length; x++){\n byteArray[x] = parseInt(hexdata.substr(x*2,2), 16);\n } */\n var bb = new Blob([byteArray], {type: \"application/octet-stream\"});\n await writableStream.write(bb);\n\n // close the file and write the contents to disk.\n await writableStream.close();\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":444,"value":"function onError(){}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":462,"value":"import {zip, zipreader} from \"@fil/jszip\"","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":466,"value":"createdFile = {\n const z = zip();\n //const data = textarea;\n var byteArray = new Uint8Array(what.slice(24113440,41656240)) //.slice(448)\n /* for (var x = 0; x < byteArray.length; x++){\n byteArray[x] = parseInt(hexdata.substr(x*2,2), 16);\n } */\n var bb = new Blob([byteArray], {type: \"application/octet-stream\"});\n z.file(\"first.segy\", bb);\n byteArray = new Uint8Array(what.slice(0,19840))\n bb = new Blob([byteArray], {type: \"application/octet-stream\"});\n z.file(\"second.segy\", bb);\n \n return z.generateAsync({ type: \"blob\" });\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":476,"value":"function writeZIP(){\n const z= zip();\n const ext =\".sgy\"\n // loop over the files and add them to the zip archive\n for (let i=0;i}