用C++写一个从shape文件中读取线数据的代码
时间: 2023-06-18 19:07:37 浏览: 62
以下是一个简单的示例代码,可以读取一个shape文件中的线数据:
```c++
#include <iostream>
#include <fstream>
using namespace std;
struct ShapeFileHeader {
int fileCode;
int unused1[5];
int fileLength;
int version;
int shapeType;
double xMin;
double yMin;
double xMax;
double yMax;
double zMin;
double zMax;
double mMin;
double mMax;
};
struct ShapeRecordHeader {
int recordNumber;
int contentLength;
};
struct ShapeLine {
int shapeType;
double xMin;
double yMin;
double xMax;
double yMax;
int numParts;
int numPoints;
int* parts;
double* points;
};
void readShapeFileHeader(ifstream& file, ShapeFileHeader& header) {
file.read((char*)&header, sizeof(header));
}
void readShapeRecordHeader(ifstream& file, ShapeRecordHeader& header) {
file.read((char*)&header, sizeof(header));
}
void readShapeLine(ifstream& file, ShapeLine& line) {
file.read((char*)&line.shapeType, sizeof(line.shapeType));
file.read((char*)&line.xMin, sizeof(line.xMin));
file.read((char*)&line.yMin, sizeof(line.yMin));
file.read((char*)&line.xMax, sizeof(line.xMax));
file.read((char*)&line.yMax, sizeof(line.yMax));
file.read((char*)&line.numParts, sizeof(line.numParts));
file.read((char*)&line.numPoints, sizeof(line.numPoints));
line.parts = new int[line.numParts];
for (int i = 0; i < line.numParts; i++) {
file.read((char*)&line.parts[i], sizeof(int));
}
line.points = new double[line.numPoints * 2];
for (int i = 0; i < line.numPoints * 2; i++) {
file.read((char*)&line.points[i], sizeof(double));
}
}
int main() {
ifstream file("lines.shp", ios::binary);
if (!file.is_open()) {
cout << "Failed to open file." << endl;
return 0;
}
ShapeFileHeader fileHeader;
readShapeFileHeader(file, fileHeader);
if (fileHeader.shapeType != 3) {
cout << "Not a polyline shapefile." << endl;
return 0;
}
ShapeLine line;
while (!file.eof()) {
ShapeRecordHeader recordHeader;
readShapeRecordHeader(file, recordHeader);
if (recordHeader.contentLength == 0) {
break;
}
readShapeLine(file, line);
// Do something with the line data...
delete[] line.parts;
delete[] line.points;
}
file.close();
return 0;
}
```
这个代码使用了 C++ 的文件操作和结构体,通过读取 shape 文件头和每个记录的头部信息,以及每个记录中的线数据,来读取 shape 文件中的线数据。