I want to remove all the points that lie outside the contours of the country map, so I can just keep the points that lies inside the country. How can I do this easier than removing all the points one by one?
As described below, you can select points in or out of your contour by
- On your country layer where you have contours, click on the outermost contour to select.
- Open the menu
Vector | Spatial Query | Spatial Query
- It will open the
- Select source features from:
- Where the feature:
- Reference features of:
Your polygon (Contour)-
- And use the result to:
Create new selection
- Click on Apply
- You will see
Result feature ID'slists selected points.
- Close to close this window.
- Open the Attribute table of your points layer. Selected points will be highlighted.
- Click on
Invert selectionicon or Ctrl+R.
Edit mode(pencil icon) and
Delete selected features.
Step 0. Please create a polygon layer which follows the contour (is it a country boarderline, perhaps?) by digitizing.
Looking back (received comment from nmtoken), I found I have completely misunderstood the question.
QGIS toolbar has a
Select Feature(s) tool. When you click on small black triangle, it opens a drop-down menu. You will see
Select Features by Freehand.
Now you can draw the selection polygon following the contour line you see on the WMS background image. These selected points can, of course, be deleted at once.