4

Im new to QGIS and I just cannot figure out how to do this one hopefully simple thing:

I have a bunch of points in shapefile and i need to move some of them around by hand / coordinates. I've understood, that if i move points by hand its possible to update their new xy to attributes table by field calculators $x and $y operators (Just select the column and insert that operator i suppose?).

However, how about reverse? I thought that the features position on screen could be changed by editing the xy columns on attribute table...but the point remains on the same old location. Am i doing something wrong?

thanks!

| improve this question | |
2

You're not doing anything wrong - the attributes you see are not directly connected to the spatial shape itself. The attributes of a shapefile may show geographic coordinates - but only those that were calculated, once-off, previously. The relationship doesn't work the other way, as you've discovered.

The .shp file itself holds the geographic data for features, and the associated .dbf holds the attribute information for each feature.

Have a look at the shapefile technical specs from ESRI or a more readable Wikipedia summary.

| improve this answer | |
  • 1
    It may be prudent to point out that this isn't just limited to a shapefile. The same situation occurs for any type of data storage. The shape or geom field that holds the coordinates used to draw the features is encoded separately from other attribute fields that may be filled with x and y coordinates. – Get Spatial Oct 11 '12 at 15:01
  • Thanks - i was afraid that it might be something like that, but i had slight hope that there might be somekind of "magical widget" hidden in qgis to save my day once again, but can get around this. Thanks again! – iippo Oct 11 '12 at 15:13
  • 1
    A rapid way to 'see' the real coordinates out of a shapefile, open the attribute table in QGIS, invert the selection (so that all are selected), copy to clipboard, and with CTRL V paste into your favourite spreadsheet program. The first two columns will be the coordinates in the form of WKT (Well Known Text) which works for points, lines, polygons. To import back into QGIS via the Delimited Text importer, you may have to edit out all the " . Notepad++ is the weapon of choice for that. At least all that works w QGIS 1.8 on Win7. – Willy Oct 14 '12 at 10:21

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.