[Qgis-user] editing for polygons

[Ramon Andiñach]

On 10/02/2014, at 07:53 , Kevin Caldwell wrote:

> Hi, 
> A new user here and having some issues editing (reshaping mostly) polygons.  These are generally polygons that abut each other within large property boundaries and which represent various forested or wetland habitat types, as well as smaller 'island' (or ring?) polygons that represent small pools, seeps, or rock outcrops (etc).   I am having good success w/ the reshape tool, but I can't seem to:   
> 
> 1) move vertices (such as enlarging or reshaping the boundaries of a pool)  - when I do so the former boundary lines still seem to show rather than the space moving out wider without lines showing...the help online doesn't seem to clarify this.   Perhaps when I save the layer edits that will change but I'm nervous to do that and wreck the original shape.   

If your pools are rings (holes in a bigger polygon filled by another polygon), then my guess would be that your bigger poly is hiding the ring polygon.
Have a look at Settings-> Snapping options. If you have the "Enable Toplogoical Editing" active then where you have points in common between polygons if you move one, then QGIS moves it for both layers. This works for line intersections too.

-ramon.
https://www.qgis.org/en/docs/user_manual/working_with_vector/editing_geometry_attributes.html#topological-editing
and this figure : https://www.qgis.org/en/docs/user_manual/working_with_vector/editing_geometry_attributes.html#figure-edit-1