Creating matrix of points inside polygon using QGIS

Question

How do I create a matrix of points (e.g. 3.5 x 0.5 meters), with a defined orientation, inside a polygon?

I have to plan the arrangement of plants in a grove in order to plan an irrigation system.

Answer 1

The easiest would be to create the grid for the whole region using the Vector->Reasearch Tools->Vector Grid tool, then clip out the part of the grid that's in the grove using the Vector->Geoprocessing->Clip tool

Answer 2

Cause i don't know the details, i can only give general hints.

I would create 2 helper lines at both ends of the field.

In the SEXTANTE toolbox, there is the function "Densify geometry given interval". Apply this function to the helper lines with an interval of 3.5. This adds new nodes in this interval, so you have an end-vertex for each row.

Create a new line layer for your rows. Set snapping options to the vertices of the helper lines.

Draw your rows from those vertices with 3.5m distance.

Use the same function to densify your rows with the interval of 0.5.

Then use the "Extraxt nodes" function (also in SEXTANTE or through Vector > Geometry Tools) and get a point layer from your rows.

This will of course only work when the field is quite rectangular. If you need curves in your lines, you will need more helper lines in between and carefully position those with a lot of measuring and calculating to get exact results. Using CAD-Tools and/or "Improved Polygon Capturing 2"-plugin to create parallel lines, or lines of fixed lenghts or angle will also help.