【发布时间】：2019-04-29 16:11:20
【问题描述】：
我目前正在编写代码以读取 .las（激光雷达点数据）文件。读入文件后，我创建了一个指针来遍历所有点。但是，它给了我一个 bad_alloc 错误。
我唯一能想到的是，标头的大小与 las 文件标头指定的大小不同。我仔细检查了我的标题，我认为我没有发现任何问题。
Header 和 PointRecord3 中的所有标题变量都来自这个documentation，分别是第 3 页和第 10 页。
更新：读入的点数为 402,673,112。但是，当我在其他激光雷达软件中打开它仔细检查时，点数只有 5,104,152。我相信这是因为我在用 C++ 打开之前在其他软件中过滤了云，因此减少了点数。
这是我的代码：
#ifndef POINTCLOUD_H
#define POINTCLOUD_H
#pragma once
#include <string>
class PointCloud
{
public:
PointCloud(const std::string &path);
private:
struct __attribute__((packed)) Header {
char magic[4];
uint16_t fileourceID;
uint16_t globalEncoding;
uint32_t guiData1;
uint16_t guiData2;
uint16_t guiData3;
uint8_t guiData[8];
uint8_t versionMaj, versionMin;
char systemIdentifer[32];
char genSoftware[32];
uint16_t creationDay, creationYear;
uint16_t headerSize;
uint32_t pointDataOffset;
uint32_t numVarLenRecords;
uint8_t pointDataRecordFormat;
uint16_t pointDataRecordLen;
uint32_t numberOfPoints;
uint32_t numPointsByReturn[5];
double scaleX, scaleY, scaleZ;
double offX, offY, offZ;
double minX, minY, minZ;
double maxX, maxY, maxZ;
};
struct __attribute__((packed)) PointRecord3 {
uint32_t X, Y, Z;
uint16_t intensity;
uint8_t flags;
uint8_t classification;
uint8_t scanAngleRank;
uint8_t userData;
uint16_t pointSourceID;
double gpsTime;
uint16_t red;
uint16_t green;
uint16_t blue;
};
#include "PointCloud.h"
#include <fstream>
#include <iostream>
#include <string>
#include <assert.h>
using namespace std;
PointCloud::PointCloud(const string &path)
{
read(path);
}
void PointCloud::read(const string &path) {
ifstream in(path.c_str(), ios::binary );
if(in.is_open()){
Header header;
in.read((char *)&header, sizeof(header));
assert(header.versionMaj == 1 && header.versionMin == 2);
cout << "headerSize " << header.headerSize << " == " << sizeof(header) << " size of header struct" <<endl;
cout << "FILE TYPE: LAS " << (int)header.versionMaj << "." << (int)header.versionMin << endl;
cout << "POINT DATA OFFSET: " << (int)header.pointDataOffset <<endl;
cout << "POINT DATA RECORD FORMAT: " << (int)header.pointDataRecordFormat <<endl;
cout << "NUMBER OF POINTS: " << (int)header.numberOfPoints << endl;
PointRecord3 *points = new PointRecord3[header.numberOfPoints];
in.seekg(header.pointDataOffset);
for(uint32_t i = 0; i < header.numberOfPoints; i++) {
in.read((char *) (points + i), sizeof(*points));
}
if(in.good()) {
throw runtime_error("error");
}
delete points;
} else {
cout << "file not opened" << endl;
}
}
任何帮助将不胜感激！
这里也是 LAS 文件头的输出：
file signature: 'LASF'
file source ID: 0
global_encoding: 0
project ID GUID data 1-4: 00000000-0000-0000-0000-000000000000
version major.minor: 1.2
system identifier: 'EXPORT'
generating software: 'RiSCAN_PRO'
file creation day/year: 317/2018
header size: 227
offset to point data: 313
number var. length records: 1
point data format: 3
point data record length: 34
number of point records: 5104152
number of points by return: 5104152 0 0 0 0
scale factor x y z: 0.00025 0.00025 0.00025
offset x y z: 267805 3197054 13
min x y z: 267804.25250 3196596.64500 -1.89000
max x y z: 268760.27000 3197586.23000 23.33000
variable length header record 1 of 1:
reserved 43707
user ID 'LASF_Projection'
record ID 34735
length after header 32
description 'GeoKeyDirectoryTag (mandatory)'
GeoKeyDirectoryTag version 1.1.0 number of keys 3
key 1025 tiff_tag_location 0 count 1 value_offset 2 - GTRasterTypeGeoKey: RasterPixelIsPoint
key 1024 tiff_tag_location 0 count 1 value_offset 3 - GTModelTypeGeoKey: ModelTypeGeocentric
key 2048 tiff_tag_location 0 count 1 value_offset 4326 - GeographicTypeGeoKey: GCS_WGS_84
reporting minimum and maximum for all LAS point record entries ...
X -2989 3821075
Y -1829412 2128911
Z -59559 41318
intensity 32767 32768
return_number 1 1
number_of_returns 1 1
edge_of_flight_line 0 0
scan_direction_flag 1 1
classification 0 0
scan_angle_rank 0 0
user_data 0 0
point_source_ID 0 0
gps_time 0.000000 0.000000
Color R 0 0
G 0 0
B 0 0
number of first returns: 5104152
number of intermediate returns: 0
number of last returns: 5104152
number of single returns: 5104152
overview over number of returns of given pulse: 5104152 0 0 0 0 0 0
histogram of classification of points:
5104152 never classified (0)
【问题讨论】：
-
你想要
delete[] points;。你的程序在崩溃之前走了多远？是否输出blah？ -
您说“.las 文件”，好像每个人都知道那是什么。我们没有。什么是“.las”文件？
-
我敢打赌，如果你写出你读到的点数，你的谜团就会被解开。
-
在现代 C++ 中使用智能指针和容器。 不是手动内存管理。
-
@p0ps1c1e 尝试创建大小约为 11GB 的数组失败并不奇怪。您可能需要考虑内存映射文件而不是读取文件。
标签： c++ pointers bad-alloc las