simple command costmap api - first few functions

[stevedanomodolor]

Signed-off-by: Stevedan Ogochukwu Omodolor stevedan.o.omodolor@gmail.com

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Basic Info

Info	Please fill out this column
Ticket(s) this addresses	(add tickets here #3151 )
Primary OS tested on	(Ubuntu)
Robotic platform tested on	(gazebo )

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Description of contribution in a few bullet points

• Add a costmap API for OccupancyGrid messages coming into the Simple Commander API
• Constructor for OccupancyGrid which stores the relevant information
• Implementation of the following first few functions
  • getSizeInCellsX / getSizeInCellsY
  • getSizeInMetersX / getSizeInMetersY
  • getOriginX / getOriginY
  • getResolution
  • getGlobalFrameID
  • getCostmapTimestamp

Description of documentation updates required from your changes

• Added new api, documentation on this api might be required in the simple commander page documentation.

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Future work that may be required in bullet points

• Implementation of the following functions
  • getCost at map pixels and index
  • setCost at map pixels
  • mapToWorld
  • worldToMap
  • getIndex

Related issue

• Simple Commander Costmap API #3151

For Maintainers:

• Check that any new parameters added are updated in navigation.ros.org
• Check that any significant change is added to the migration guide
• Check that any new features OR changes to existing behaviors are reflected in the tuning guide
• Check that any new functions have Doxygen added
• Check that any new features have test coverage
• Check that any new plugins is added to the plugins page
• If BT Node, Additionally: add to BT's XML index of nodes for groot, BT package's readme table, and BT library lists

[mergify]

@stevedanomodolor, please properly fill in PR template in the future. @SteveMacenski, use this instead.

• Check that any new parameters added are updated in navigation.ros.org
• Check that any significant change is added to the migration guide
• Check that any new features OR changes to existing behaviors are reflected in the tuning guide
• Check that any new functions have Doxygen added
• Check that any new features have test coverage
• Check that any new plugins is added to the plugins page
• If BT Node, Additionally: add to BT's XML index of nodes for groot, BT package's readme table, and BT library lists

[SteveMacenski]

LGTM, just needs the functions implemented!

[stevedanomodolor]

@SteveMacenski Task completed

[codecov]

Codecov Report

Merging #3159 (2b09111) into main (1d9d3c6) will decrease coverage by 0.11%.
The diff coverage is n/a.

❗ Current head 2b09111 differs from pull request most recent head 7cba887. Consider uploading reports for the commit 7cba887 to get more accurate results

@@            Coverage Diff             @@
##             main    #3159      +/-   ##
==========================================
- Coverage   83.10%   82.99%   -0.12%     
==========================================
  Files         339      339              
  Lines       15233    15233              
==========================================
- Hits        12660    12642      -18     
- Misses       2573     2591      +18     

Impacted Files	Coverage Δ
nav2_dwb_controller/dwb_critics/src/path_align.cpp	86.36% <0.00%> (-9.10%)	⬇️
nav2_navfn_planner/src/navfn_planner.cpp	90.57% <0.00%> (-4.72%)	⬇️
...av2_dwb_controller/dwb_critics/src/oscillation.cpp	90.66% <0.00%> (-4.00%)	⬇️
...ostmap_2d/plugins/costmap_filters/speed_filter.cpp	94.49% <0.00%> (-1.84%)	⬇️
nav2_navfn_planner/src/navfn.cpp	93.03% <0.00%> (-0.28%)	⬇️
nav2_amcl/src/amcl_node.cpp	71.65% <0.00%> (-0.15%)	⬇️

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[SteveMacenski]

LGTM.

It would be good to add a new section to https://navigation.ros.org/commander_api/index.html for "Costmap API" with the same kind of table from the "Commander API" section with a short paragraph at the top explaining:

• This is a Python3 API for costmap 2d messages from the stack
• Provides the basic conversion, get/set, and handling semantics found in the costmap 2d C++ API

[stevedanomodolor]

LGTM.

It would be good to add a new section to https://navigation.ros.org/commander_api/index.html for "Costmap API" with the same kind of table from the "Commander API" section with a short paragraph at the top explaining:

• This is a Python3 API for costmap 2d messages from the stack
• Provides the basic conversion, get/set, and handling semantics found in the costmap 2d C++ API

That sound good. I will make the changes as soon as possible

[stevedanomodolor]

• This is a Python3 API for costmap 2d messages from the stack
• Provides the basic conversion, get/set, and handling semantics found in the costmap 2d C++ API

Related pull request for documentation.

• Python cost api documentation docs.nav2.org#342

[SteveMacenski]

@stevedanomodolor would you have interest in working on a simplified rclpy API with me (e./g. rcl_simple_py)? I'm working on a currently private repository to create a simplified ROS 1-like API for both python and C++. I've gotten started with python first since I think its easier to quickly jot something up for it and then translate to C++ once finished.

I'm just getting started with it today. I could use some help completing the API, writing tests to make sure everything works as expected, and a few code samples to make the point clear. Figure I have no particular need to do everything alone if there's interest!

[stevedanomodolor]

@SteveMacenski Yes, I would love to

[SteveMacenski]

Sweet, I added you to the repo but you should join the nav2 slack (invite link in readme https://github.com/ros-planning/navigation2) so we can chat about what needs to be done / do. But I think the bullet on creating the timer/time/rate/duration simplified wrapper classes would be a good starting point. The tl;dr there is (1) remove callback groups / executor / QoS settings from the constructor and use (2) use double seconds for all APIs involving time (3) try to mimick roughly speaking the ROS 1 API where reasonable.

You can see some examples in the rclpy simple repo already, but you don't need to reimplement these things from scratch, just wrap about the rclpy content with simplified APIs for external users that sets default QoS / etc so the user doesn't have to think about it or know anything about it. If you look at the readme, I give a decent overview of the intention.

There may be some things that already are sufficiently simple (e.g. service servers) so its just a straight through class inheritance wrapper just to offer the capability through this API so users don't need to mix and match rcl_simple_py with rclpy to get the bare minimum set of capabilities. I think my TODO list in the readme gives a good list of all the "things" that need to be added, but please let me know if I missed anything or you have any other ideas of utilities / tools / wrappers that would be helpful to have!