3

I have points on a map of the globe given with lat|long coordinates. I want to create a rectangular buffer around each one, but I want to be able to set the dimension of this buffer in metres. The boxes will have dimensions of around 100m x 200m so I need my solution to be pretty accurate. The tools I've found so far assume (fairly) that the parameters I pass to it (width, height) are of the same type as the point coordinates. Instead I want to pass parameters in metres whereas my point coordinates are lat long values.

Any ideas?

Converting metres to degrees somehow is an option but I'm worried about accuracy.

2

If Qgis is not only the option, then you can do it using java script on Web page also.

Using js2shape.js and geographiclib.js you can achieve most accurate results.

You can visit this working link called CSV2Shape

You just need to create your point layer to Csv file with 2 mandatory fields i.e, latitude and longitude in degree decimal format.

You can also create buffers or rectangles with fixed values or separate values as against each row.

You can download the results in shape file or kml format.

1

In QGIS 3.0, you could try Geometry by expression tool. (In Processing Toolbox | Vector geometry`).

For instance, if you are in UTM30N (EPSG:32630), expression would be

 transform(
  bounds(
   combine(translate(transform($geometry, 'EPSG:4326', 'EPSG:32630'),-100/2, -200/2), 
           translate(transform($geometry, 'EPSG:4326', 'EPSG:32630'), 100/2,  200/2))), 
 'EPSG:32630', 'EPSG:4326'
 )

Then this

enter image description here

would become:

enter image description here

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