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mapviz - transforming local xy coordinate frame to tile map lat/lon coordinate frame

asked 2017-04-20 15:25:01 -0500

obotic gravatar image

I am running a tile map plugin for mapviz. As I move my mouse on the map I can see the GPS coordinates changing on the ui interface. I also used the swri_transform_util to give my robot a lat/lon xy origin. Now I am trying to use the point click publisher to get lat/lon coordinates when a place on the map is clicked. I am not sure what the tile map frame is however. I can get my robot's local xy position when I click on the map, but not sure how to transform it to the lat/lon coordinate.

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answered 2017-04-21 00:22:37 -0500

obotic gravatar image

As I was looking in some of the other swri packages there is a function called Wgs84FromLocalXy in package swri_transform_util. It takes local xy, referenced lat/lon, and outputs the transform(no tf). So it looks like in my subscriber I can call this function. I'm not sure if this is the best way to go about it, but it seems to work for me right now.

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That is probably used because lat/long cannot be directly converted into metres in X and Y as used by tf, because they are angles referenced against a spheroid, not a perfect sphere.

Geoff gravatar image Geoff  ( 2017-04-21 00:45:53 -0500 )edit

answered 2017-04-20 22:30:37 -0500

Geoff gravatar image

Use the view_frames utility from tf to see what the frames are in your system. From that you should be able to make a good guess which is correct for the tile map frame.

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Thanks Geoff, I forgot about that utility. I saw that there was no frame from the tile map which then made me realize maybe the transform is done another way.

obotic gravatar image obotic  ( 2017-04-21 00:22:35 -0500 )edit

answered 2018-08-08 06:41:10 -0500

Stepan Kostusiev gravatar image

To get lat/lon from Point Click Publisher you can set frame: /wgs84

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Asked: 2017-04-20 15:25:01 -0500

Seen: 681 times

Last updated: Aug 08 '18