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POtrouble reading structure from stream, or bytes rather
 

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  1. POtrouble reading structure from stream, or bytes rather
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    <p>I'm trying to read a LAS File 1.3 Header from a file.</p> <p>In every single header that I've seen, The first thing i expect to read is the Format Signature which is always "LASF".</p> <p>When i try and read the file, All I'm seeing is 'ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ'</p> <p>I know the header size is 227, I tried to even just read a length of 227 straight from the file but i still don't read what I'm supposed to. I hope this makes sense.</p> <p>this is what i've tried:</p> <pre><code>typedef struct Header { char File_Signature[4]; USHORT SourceID; USHORT Reserved1; UINT GUID1; USHORT GUID2; USHORT GUID3; char GUID4[8]; BYTE VersionMajor; BYTE VersionMinor; char SystemID[32]; char GeneratingSoftware[32]; USHORT DOY; USHORT YEAR; USHORT HeaderSize; UINT PointOffset; INT NumberOfVariableLengthRecords; BYTE PointDataFormatID; USHORT PointDataRecordLength; INT NumberOfPointRecords; UINT NumberofPointsByReturn1; UINT NumberofPointsByReturn2; UINT NumberofPointsByReturn3; UINT NumberofPointsByReturn4; UINT NumberofPointsByReturn5; double XScaleFactor; double YScaleFactor; double ZScaleFactor; double Xoffset; double Yoffset; double Zoffset; double MaxX; double MinX; double MaxY; double MinY; double MaxZ; double MinZ; } LasHeader; void OpenLasFile() { //THIS DOES NOT WORK char buffer[227]; ifstream myFile ("C:\atlass\area_cov.las"); myFile.read (buffer, 227); //NOT WORK, TRIED THIS TOO ifstream input_file("C:\atlass\area_cov.las", ios::binary); LasHeader header; input_file.read((char*)&amp;header, sizeof(header)); input_file.close(); //ALL DATA OUTPUT'ed ARE 'ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ' } </code></pre> <p>This is a block of binary from the file I'm trying to read.</p> <pre><code>4C4153460000000001000000020003003132333435363738010241746C6173732041746C6173436F72652020202020202020202020202020202041746C6173436F726520202020202020202020202020202020202020202020201E01DC07E300E300000000000000011C0014012F0014012F0000000000000000000000000000000000FCA9F1D24D62503FFCA9F1D24D62503FFCA9F1D24D62503F00000000B05320410000000024FF53410000000000000000E7B3FA8388A920411B5611E9BC1B20417710D27C2711544114A5EC807EF45341C520B072685D684037894160E5D012C021BE92FF06661701A9600000D803C902E2000100AC7136BDE325044137 </code></pre> <p>My question is: Why am i Reading garbage values, what have i done wrong?</p> <p>-------------------- UPDATE --------------------------</p> <p>I tested this and it worked, So it must be a problem reading the file, can anyone help?</p> <p>what worked was:</p> <pre><code>unsigned char rawData[552] = { 0x4C, 0x41, 0x53, 0x46, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x02, 0x00, 0x03, 0x00, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x01, 0x02, 0x41, 0x74, 0x6C, 0x61, 0x73, 0x73, 0x20, 0x41, 0x74, 0x6C, 0x61, 0x73, 0x43, 0x6F, 0x72, 0x65, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x41, 0x74, 0x6C, 0x61, 0x73, 0x43, 0x6F, 0x72, 0x65, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x1E, 0x01, 0xDC, 0x07, 0xE3, 0x00, 0xE3, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x1C, 0x00, 0x14, 0x01, 0x2F, 0x00, 0x14, 0x01, 0x2F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFC, 0xA9, 0xF1, 0xD2, 0x4D, 0x62, 0x50, 0x3F, 0xFC, 0xA9, 0xF1, 0xD2, 0x4D, 0x62, 0x50, 0x3F, 0xFC, 0xA9, 0xF1, 0xD2, 0x4D, 0x62, 0x50, 0x3F, 0x00, 0x00, 0x00, 0x00, 0xB0, 0x53, 0x20, 0x41, 0x00, 0x00, 0x00, 0x00, 0x24, 0xFF, 0x53, 0x41, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xE7, 0xB3, 0xFA, 0x83, 0x88, 0xA9, 0x20, 0x41, 0x1B, 0x56, 0x11, 0xE9, 0xBC, 0x1B, 0x20, 0x41, 0x77, 0x10, 0xD2, 0x7C, 0x27, 0x11, 0x54, 0x41, 0x14, 0xA5, 0xEC, 0x80, 0x7E, 0xF4, 0x53, 0x41, 0xC5, 0x20, 0xB0, 0x72, 0x68, 0x5D, 0x68, 0x40, 0x37, 0x89, 0x41, 0x60, 0xE5, 0xD0, 0x12, 0xC0, 0x21, 0xBE, 0x92, 0xFF, 0x06, 0x66, 0x17, 0x01, 0xA9, 0x60, 0x00, 0x00, 0xD8, 0x03, 0xC9, 0x02, 0xE2, 0x00, 0x01, 0x00, 0xAC, 0x71, 0x36, 0xBD, 0xE3, 0x25, 0x04, 0x41, 0x37, 0xB9, 0x92, 0xFF, 0x77, 0x58, 0x17, 0x01, 0xD7, 0x60, 0x00, 0x00, 0xE2, 0x0A, 0xC9, 0x02, 0xE2, 0x00, 0x01, 0x00, 0x4B, 0x90, 0x11, 0x90, 0xE3, 0x25, 0x04, 0x41, 0x00, 0xBF, 0x92, 0xFF, 0x98, 0x3A, 0x17, 0x01, 0x2B, 0x62, 0x00, 0x00, 0x23, 0x0A, 0x49, 0x02, 0xE4, 0x00, 0x01, 0x00, 0xBF, 0xF5, 0x61, 0xBD, 0xE3, 0x25, 0x04, 0x41, 0x1A, 0xBD, 0x92, 0xFF, 0x30, 0x11, 0x17, 0x01, 0xE4, 0x62, 0x00, 0x00, 0xDF, 0x08, 0x49, 0x02, 0xE4, 0x00, 0x01, 0x00, 0xF8, 0x6E, 0xF3, 0xA6, 0xE3, 0x25, 0x04, 0x41, 0x01, 0xBE, 0x92, 0xFF, 0x67, 0xE7, 0x16, 0x01, 0x83, 0x63, 0x00, 0x00, 0xCB, 0x06, 0x49, 0x02, 0xE5, 0x00, 0x01, 0x00, 0x0B, 0xF3, 0x1E, 0xA7, 0xE3, 0x25, 0x04, 0x41, 0xF2, 0xBB, 0x92, 0xFF, 0x99, 0xD9, 0x16, 0x01, 0x6D, 0x63, 0x00, 0x00, 0x03, 0x09, 0x49, 0x02, 0xE5, 0x00, 0x01, 0x00, 0x82, 0x1C, 0x94, 0x90, 0xE3, 0x25, 0x04, 0x41, 0xFA, 0xBE, 0x92, 0xFF, 0x98, 0xBE, 0x16, 0x01, 0x13, 0x63, 0x00, 0x00, 0xFF, 0x08, 0x49, 0x02, 0xE5, 0x00, 0x01, 0x00, 0xE5, 0xF0, 0x49, 0xA7, 0xE3, 0x25, 0x04, 0x41, 0xEE, 0xBC, 0x92, 0xFF, 0xDE, 0xB0, 0x16, 0x01, 0x04, 0x63, 0x00, 0x00, 0x8E, 0x0B, 0x49, 0x02, 0xE5, 0x00, 0x01, 0x00, 0x95, 0xA0, 0xBF, 0x90, 0xE3, 0x25, 0x04, 0x41, 0xD2, 0xBD, 0x92, 0xFF, 0x19, 0x88, 0x16, 0x01, 0xA9, 0x63, 0x00, 0x00, 0xD1, 0x08, 0x49, 0x02, 0xE7, 0x00, 0x01, 0x00, 0xA7, 0x24, 0xEB, 0x90, 0xE3, 0x25, 0x04, 0x41, 0xA8, 0xBE, 0x92, 0xFF, 0x29, 0x64, 0x16, 0x01, 0x97, 0x63, 0x00, 0x00, 0xFD, 0x04, 0x49, 0x02, 0xE7, 0x00, 0x01, 0x00, 0xC4, 0xF0, 0x11, 0x91, 0xE3, 0x25, 0x04, 0x41, 0x79, 0xD0, 0x92, 0xFF, 0xD0, 0x70, 0x17, 0x01, 0x30, 0x61, 0x00, 0x00, 0x60, 0x02, 0xC9, 0x02, 0xE2, 0x00, 0x01, 0x00, 0x91, 0x65, 0xC1, 0x44, 0xE4, 0x25, 0x04, 0x41, 0x12, 0xC7, 0x92, 0xFF, 0x02, 0x5E, 0x17, 0x01, 0x79, 0x61, 0x00, 0x00, 0x79, 0x05, 0xC9, 0x02, 0xE2, } ; LasHeader test; memcpy(&amp;test, rawData, sizeof(test)); </code></pre>
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    1. COThanks, I checked it and it appears not to be open, Why would that be? I tried this: myFile.open("C:\atlass\area_cov.las"); if (myFile.is_open()) { myFile.read (buffer, 227); }
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    2. COI think you should add `ios::in`: `ifstream input_file("C:\atlass\area_cov.las", ios::in | ios::binary);`
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      1. POtrouble reading structure from stream, or bytes rather
      1. USlolando
    3. COYou need to escape your backslashes. `"c:\\atlass\\area_cov.las"`
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      1. POtrouble reading structure from stream, or bytes rather
      1. USRetired Ninja
 

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