ros2 rviz2 制作一个类似椭圆形跑道的地图，使用C++语言

可以使用ROS2和rviz2来构建椭圆形跑道地图，以下是简单的步骤：

1. 创建ROS2工作空间并初始化catkin工作空间

mkdir -p ~/ros2_ws/src
cd ~/ros2_ws
colcon build
source ~/ros2_ws/install/local_setup.bash

2. 创建一个ROS2 package并添加依赖项

cd ~/ros2_ws/src
ros2 pkg create my_map
cd my_map
vim package.xml

在`package.xml`中添加以下依赖项：

<build_depend>rviz2</build_depend>
<exec_depend>rviz2</exec_depend>
<build_depend>visualization_msgs</build_depend>
<exec_depend>visualization_msgs</exec_depend>

3. 创建一个C++节点来发布椭圆形跑道地图的数据

cd ~/ros2_ws/src/my_map
mkdir src
vim src/my_map_node.cpp

在`my_map_node.cpp`中添加以下代码：

#include <chrono>
#include <memory>

#include "rclcpp/rclcpp.hpp"
#include "std_msgs/msg/string.hpp"
#include "visualization_msgs/msg/marker.hpp"

using namespace std::chrono_literals;

class MyMapNode : public rclcpp::Node
{
public:
  MyMapNode()
  : Node("my_map_node")
  {
    publisher_ = this->create_publisher<visualization_msgs::msg::Marker>("my_map_marker", 10);
    timer_ = this->create_wall_timer(500ms, std::bind(&MyMapNode::publish_marker, this));
  }

private:
  void publish_marker()
  {
    auto marker = std::make_unique<visualization_msgs::msg::Marker>();
    marker->header.frame_id = "map";
    marker->header.stamp = this->now();
    marker->ns = "my_map_ns";
    marker->id = 0;
    marker->type = visualization_msgs::msg::Marker::CYLINDER;
    marker->action = visualization_msgs::msg::Marker::ADD;
    marker->pose.position.x = 0.0;
    marker->pose.position.y = 0.0;
    marker->pose.position.z = 0.0;
    marker->pose.orientation.x = 0.0;
    marker->pose.orientation.y = 0.0;
    marker->pose.orientation.z = 0.0;
    marker->pose.orientation.w = 1.0;
    marker->scale.x = 10.0;
    marker->scale.y = 10.0;
    marker->scale.z = 2.0;
    marker->color.r = 0.0;
    marker->color.g = 1.0;
    marker->color.b = 0.0;
    marker->color.a = 1.0;
    marker->lifetime = rclcpp::Duration(0s);

    publisher_->publish(std::move(marker));
  }

  rclcpp::Publisher<visualization_msgs::msg::Marker>::SharedPtr publisher_;
  rclcpp::TimerBase::SharedPtr timer_;
};

int main(int argc, char * argv[])
{
  rclcpp::init(argc, argv);
  auto node = std::make_shared<MyMapNode>();
  rclcpp::spin(node);
  rclcpp::shutdown();
  return 0;
}

这个节点会发布一个Cylinder类型的Marker，该Marker代表椭圆形跑道。

4. 编译和运行节点

cd ~/ros2_ws
colcon build --packages-select my_map
ros2 run my_map my_map_node

5. 在rviz2中添加Marker显示

打开rviz2，点击`Add`按钮，在弹出的菜单中选择`Marker`，然后在弹出的Marker属性窗口中，将`Topic`设置为`my_map_marker`，然后点击`Add Marker`按钮，就可以看到椭圆形跑道地图了。

以上就是使用ROS2和rviz2创建椭圆形跑道地图的简单步骤。