I wanted to know whether it is possible to change the coordinates of a Polygon by typing them in.
I don't want to have to manually drag them into the right position.
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Do you mean that you want to shift the whole polygon by some dx and dy values? If so, there's the Spatialite function SHiftCoords(). It takes the existing geometry, an X-shift and a Y-shift, and returns a new geometry translated by that shift.– MichaSep 25, 2012 at 10:41
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Not sure what you mean by "tipping them in"– RaynerSep 25, 2012 at 10:42
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3 Answers
Just install the Numerical Vertex Edit plug-in for QGIS. It installs a new button in the shape menu bar and allows you to numerically edit the vertex of a polygon typing the coordinates. ciao
Couldn't find the "Numerical Vertex Edit" plug-in for QGIS 3.0 Girona, but the built-in "Translate" processing tool can be used.
Before using the Translate tool, first use the ruler to measure the horizontal and vertical distances (the ruler will use the map's units; and so will Translate). If the distances are large, make sure that you have a feature that you can zoom to at your starting and ending points. Start your ruler measurement at the first location, use the Zoom-to-layer function to move the map to the second location - click again at this location to record the measurement.
Once you have the horizontal and/or vertical distances, enter these into Translate's x or y offsets (x-offsets greater than zero shift to the east, y-offsets greater than zero shift to the north). If your starting/ending locations aren't purely east/west or north/south, then you will have to repeat the measuring and translating a few times.
When you get the object near enough, you can use the Move feature in the editor.
...changing the location by entering the coordinates of the centroid would be much easier.
I have QGIS 3.4.0, after creating a polygon shapefile, start edit mode (pencil icon) then press the vertex tool button in the same toolbox. That will allow to move the vertices of the polygon. Next when the mouse is on one of the vertices press right click on the mouse "Vertex Editor" option will appear press it, and a coordinate table will appear. You can change the coordinates in that table to build the polygon with your own coords.
