Hot answers tagged

38

In QGIS 3.0, the vertex tool (same as node tool from QGIS 2.x) works a bit differently. Whether this is an improvement or not is a matter of opinion. It certainly takes a bit of getting used to. Moving a vertex 2.x: Click on a vertex or segment to enable vertex editing for that feature. Click on vertex you want to move. Without releasing the mouse, drag it ...


26

You should be using "Add Ring" tool to create a hole in the polygon. Just Select the "Add Ring" tool and digitize a hole inside the polygon. It will remove that part and create a hole.


25

Here's a python function that will select random features in a layer based on percent, ignoring current selection: def SelectRandomByPercent (layer, percent): #layer variable is the layer name in TOC #percent is percent as whole number (0-100) if percent > 100: print "percent is greater than 100" return if percent < 0: ...


24

With the Node tool (called the Vertex Editor in QGIS 3.0+) selected, simply double-click on a line segment you want to add a node to


21

No need to create a new layer. You can show your layer's vertices using the Outline: Marker line Symbol layer type. Just add a new symbol layer Add a new symbol layer; Choose Outline Marker line (top right corner); In the Marker placement, Choose "On every vertex" You can even style the marker to look like the red cross symbol used on layers in edit mode.


19

You can customize the attribute editing to various data types (predefined lists, a range of values or a date). Select a layer. Right-click > Properties. In the Properties window, click the Field tab. Select any field you want your pre-defined classes. The Value Map option will ask for your pre-defined classification values. When you start adding ...


19

I don't think there's a really simple way to do this, but one way would be to: Create a new polygon layer and create polygons over the areas you want to change the values of. Code the polygons with the desired land cover value. Convert the shapefile to a raster. Use the Raster Calculator to substitute the new values. Con(("POLYRAST" > 0),"...


18

Right-click the feature class in ArcCatalog and go to the Properties. In the Feature Extent tab, click on Recalculate. And voilà! I'm using ArcGIS 10.2.1


16

The latest inserted vertices can be removed one by one by hitting either Del or BackSpace keys. It really seems to be undocumented in the current QGIS 2.2 manual at http://docs.qgis.org/2.0/en/docs/user_manual/working_with_vector/editing_geometry_attributes.html. It would belong to the Adding Features section which tells at the moment only how to add ...


15

There are several steps I use. Ensure you are Data View NOT in Layout View (thanks MW) is easiest but don't necessarily try it second. copy the layer you need to edit, snap to and use for reference (as few as possible) to another document (for editing). make sure you don't have a definition query.


15

By default CSV layers cannot be edited. You have to save to a different format, e.g. Shapefile, before you can start editing. Update 2015-11: There's a new plugin that solves this issue called Editable GeoCSV. It can handle x and y columns for points or a WKT column. For more details see http://giswiki.hsr.ch/Editable_GeoCSV_QGIS_Plugin


15

If I understood you correctly, you have to move the selection anchor first: use edit tool and hold down the CTRL key drag selection anchor to the corner of your borderline More information in ArcGIS Help.


15

Since you're not worried about simultaneous edits on features, I'd say that in theory you have nothing to worry about. The main danger w/ QGIS is that simultaneous editors can stomp on each other's edits without noticing ("last edit wins"). For data under active editing with multiple users you might want to at least keep track of history, which you can do w/...


14

You can accomplish this with a combination of QGIS and GRASS. Import your vector layer into a GRASS mapset ( Grass | File > Import Vector Data ) Open your mapset in QGIS ( QGIS | Plugins > GRASS > Open mapset ) Add vector layer from your GRASS mapset to your QGIS project ( QGIS | Plugins > GRASS > Add GRASS vector layer ) Use v.clean.snap ( QGIS | Plugins > ...


14

Use the Plugins>Fetch Python Plugins and select: Rectangles, Ovals and Diamonds Edit your layer (polygon) and select a feature to rotate - click and hold on the edge and the shape will rotate.


14

This should do it and is a little simpler than the examples in the online help for UpdateCursor which is nevertheless worth a read. I've assumed your shapefile is in a folder called C:\temp and that structuretype is an integer field. If it is a text field just use "3" and "4" instead of 3 and 4. import arcpy features = arcpy.UpdateCursor(r"C:\temp\...


13

Take a look to OpenLayers for client side, it offers in a simply way all you seems need. As previously suggest to you by Dassouki, take a look to the example page: http://www.openlayers.org/dev/examples/ find for 'edit' For example: http://www.openlayers.org/dev/examples/editingtoolbar.html For server side I personally bet for OS project, IMO they are ...


13

The best way is to convert this shape file to file-geodatabase and build the topology in ArcGIS for "Must Not Have Gaps" and "Must Not Overlap". The important thing in building topology is cluster tolerance. This is a tolerance in which topology will remove/fix errors automatically after validating. So you should select this tolerance very carefully as big ...


13

In Snapping Options (Settings menu) enable snapping (better snapping to vertex only in your case as suggested in comments) for your layer, then using Split feature tool make a left click on the one blank space on side of the line, then make left click on the vertex where the split should occur and in the end make a right click on the blank space on the other ...


13

Generally, I also recommend using the spatial ecology tools as discussed by blah238. However, another method you could try would be to add an attribute called Random to store a random number: Then, using the field calculator on that attribute, with the Python Parser, use the following codeblock: import random def rand(): return random.random() See ...


12

The "Identify" tool will let you do this. There's a setting under Settings > Options > Map Tools tab > Open Feature Form, if a single feature is identified. Then just make sure your layer is editable, and click the feature with the identify tool.


12

If you want to interactivelly change your points coordinates, one by one, I believe you can do what you want by using the Numerical Vertex Edit Plugin. I can install it in Plugins > Fetch Python Plugins and search it by its name. After installing you will notice a new icon on you digitalizing toolbar like this . To make it active you must be editing a layer....


12

There are two ways to get at the Create Features window from the Editor toolbar: 1) Start Editing. Right-click on toolbar and select "Editor" 2) In the editor toolbar: Editor > Editing Windows > Create Features Alternatively, the right most button on the editor toolbar:


12

Start editing that shapefile, double click on said point, right click on point and "move to" and it will give you an option to type in the x and y coordinates for where you want to move the point to. the drop down also gives options to change to DD or meters etc.


12

Possible workaround, maybe good as just temporary solution for few data: Enable snapping (Settings --> Snapping Options...). Set snap to vertex and set some tolerance. Create a "dummy" line feature snapped on vertices you want move. In snapping option check Enable topological editing Activate node tool and select vertices of "dummy" line and move (hold ...


11

Quick answer: no! There's no tool like that to do that operation directly on the layer (the "Join Two Lines" plugin requires intersection). You could do it for a very simple layer by turning the lines to points (extract nodes) then joining with points2one (line output) but this would be MUCH slower than just editing by hand: Make sure you have snapping (...


11

Using QGIS you can quickly divide a given shapefile up into regular rectangles as you've shown in your example. Load the original shapefile; Use Vector|Research Tools|Vector grid and create a grid of polygons the same extent as your shapefile, with the right distance between divisions ('parameters') selected (100 in my example image below); Intersect the ...


11

The syntax problem is most likely caused be the spaces in column names. If you double-click the column names in field calculator, they will most certainly be added with quotation marks, e.g. "Catt Pop" + "Buff Pop"


11

GDAL/OGR has python bindings and a FileGDB driver, but it requires the FileGDB API SDK from ESRI (not free, but AFAIK free of charge).


11

'Long integer' won't produce decimals. Try floating point. For reference, this wiki link lists types of numbers.


Only top voted, non community-wiki answers of a minimum length are eligible