confuse readme about trasform numpy to pointcloud2
lianghongzhuo opened this issue · 0 comments
lianghongzhuo commented
When I try to transform numpy to pointcloud2, the example on readme file is confusing me:
data = np.zeros(100, dtype=[
('x', np.float32),
('y', np.float32),
('vectors', np.float32, (3,))
])
data['x'] = np.arange(100)
data['y'] = data['x']*2
data['vectors'] = np.arange(100)[:,np.newaxis]
msg = ros_numpy.msgify(PointCloud2, data)
In this example, "x"
filed and "y"
filed has a size 100, and filed "vectors"
has a size 100*3
This makes me thinking that filed "vectors"
should put the points I want to transform to ros msg, and "x"
filed and "y"
filed is the indices of it on the depth image.
This is wrong.
I took some time to realize it. So, to avoid confusion to other users, I propose to update the readme file example as follows:
points = np.random.rand(100,3)
data = np.zeros(100, dtype=[
('x', np.float32),
('y', np.float32),
('z', np.float32),
])
data['x'] = points[:, 0]
data['y'] = points[:, 1]
data['z'] = points[:, 2]
msg = ros_numpy.msgify(PointCloud2, data)