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what is for?

asked 2014-01-23 02:47:50 -0600

AbuIbra gravatar image

updated 2014-01-28 17:07:25 -0600

ngrennan gravatar image

I am using gmapping to create maps with lasers. I managed to have successful maps but since obstacles in some indoor spaces (like malls etc..) are transparent (such as glass walls and doors etc...), my project is to enhance the mapping by adding a node using sonars and the laser-created-map (and tf data of course to localise the robot in the map) to generate a more general map with the transparent obstacles in it. (the introduction is to let you know why this question and to have some advices regarding what I want to do..)

So, my question is: Are the /map frame axes (X and Y) parallel to the sides of the "rectangular map"? If not, I guess the information about the /map frame orientation is in "". No? I read in some previous question :(/question/10268/where-am-i-in-the-map/) that "in practice there's no rotation". Is "" then useless?

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answered 2014-01-23 03:03:28 -0600

dornhege gravatar image

No, it is not useless. Correct implementations should always use the orientation to transform between grid and world coordinates.

It is just that in practice in most cases the orientation is set to 0. If you ignore it, Murphy says that you'll find a map that is rotated.

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Set to 0? where? Can I set it myself to 0, just to make sure it is 0?

AbuIbra gravatar image AbuIbra  ( 2014-01-23 03:21:42 -0600 )edit

Whoever produces the map must set this. If you set it to something different than in the map originally you are making it unsafe as you're basically changing the map. You can check if it is already 0 to be safe (if you are ignoring orientation).

dornhege gravatar image dornhege  ( 2014-01-23 03:37:11 -0600 )edit

ok thank you

AbuIbra gravatar image AbuIbra  ( 2014-01-23 03:42:22 -0600 )edit

answered 2014-01-23 03:50:20 -0600

AbuIbra gravatar image

Just in case someone needs to know, in GMapping the "" is 0 (quat = [0 0 0 1]).

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Asked: 2014-01-23 02:47:50 -0600

Seen: 1,523 times

Last updated: Jan 23 '14