The size of Map message is too big

[gyeongmin6099]

Question Thank you for your marvelous work. I'm trying to run wavemap in the small area with min_cell_width : 0.05. If min_cell_width : 0.1, the size of Map message isn't too big, but it has 10 times bigger size about a few MB with min_cell_width:0.05. And It's too big to send from device to ubuntu machine in real time. Is there way to reduce the size of Map message? Thanks.

Runtime information:

• Launch file: [Custom]
• Config file: [hasehd_chunked_wavelet_octree, hashed_chunked_wavelet_integrator, continuous_beam]
• Custom setup: # For online use or personal datasets
  • depth sensor: [TOF]
  • pose source: [Odometry from PX4]

System information:

• CPU: [QRB5165]
• RAM: [8GB]
• OS: [e.g. Ubuntu 18.04]
• Wavemap
  • install: [Native]
  • version: [v1.4.0]

[victorreijgwart]

Hi @gyeongmin6099, thanks for trying out wavemap!

One setting that might help is the map/general/max_num_blocks_per_msg. Wavemap transmits the map using incremental updates. If you set max_num_blocks_per_msg to a lower value, it will also split each update into multiple smaller messages. Note that this will decrease the message size, but the bandwidth will stay the same.

Depending on your use case, there might be additional things you can configure. When you say the messages are too big, is the issue packet-loss (e.g. unreliable WiFi), is there a hard limit on the max message size (e.g. hardware limits on the embedded device), or are you having issues with limited bandwidth (e.g. slow WiFi or a radio)? How do you intend to use the maps on the Ubuntu machine? Does it run Rviz, a planner, or something else?

[gyeongmin6099]

Thank you for your fast response :) I could fix my problem by changing max_num_blocks_per_msg and There was a issure from my radio! Now I'm trying to render the 3D Map data on Rviz, But I want to change some code later so that I can render the map on web viewer or something. Thanks for your help:) Lemme close this issue

[gyeongmin6099]

Hi @victorreijgwart I have one more question! Is there a way to colorize wavemap with RGB input? If so, Do you have a plan to add the feature? Thanks a lot!

[victorreijgwart]

Hi @gyeongmin6099, great to hear that changing max_num_blocks_per_msg solved your issue!

Yes, it would be possible to add colors to the map. The main changes that would be needed would be to add a map data structure that includes a color channel (alongside the occupancy) and a compatible measurement integrator. Unfortunately, I personally won't have time to work on this in the next few months though. Would you be interested in working on this?

Let me know how it goes with rendering the maps in a browser. That'd be a really awesome feature!

[gyeongmin6099]

I'm interested in it! If this project can make 3D Map like the real world. It would be awesome!

[victorreijgwart]

@gyeongmin6099, that's great! Let's continue the discussion on how to get started in this feature request. Then others can easily find it and join.