SAGAĪnother way to do this is using SAGA GIS. It shows what may happen when the boundary points are not ordered. A polygon created with the Points2One addon, based on 6 boundary points. The figure below shows what happens if your points are not in the right order. A polygon created with the Points2One plugin, which was used to convert the 5 boundary points to a polygon The second part can be done by the Points2One plug-in. The first part, you will have to take care of – the tool assumes that the points are ordered. To capture irregular areas, you need (1) ordered points, and (2) a way to connect these points to a boundary. This makes this function suitable if you have only two points (of the diagonally opposing corners of a rectangle). You can see it as a rubber band wrapped around the “outside” points. It is the smallest convex set containing all points. The Convex hull can be created with the function Convex hull(s) under the menu Vector | Geoprocessing tools | convex hull). Delaunay triangulation polygon Convex hull The result shows all borders possible by connecting the given points. ![]() Note that the order of the points is not important as all points are connected to each other. The Delaunay triangulation polygons can be created with the function of the same name under menu Vector | Geometry Tools. Point to polygon fileĭepending on the desired output, there are various options to convert a point file to a polygon file. As you can see, the plugin includes various options for import and export of attribute tables. If installed, you can find the plugin under the Vector menu. The tool supports both Excel and Libre/OpenOffice spreadsheets. With the XY tool, you can import the spreadsheet directly. Add delimited text layer’ plug-in XY tool Note that if you want to keep the point layer, you need to save it. Save your spreadsheet as a comma delimited text file (csv) Then, use the ‘Add delimited text layer’ plug-in (see Figure 1) to create a point layer. In QGIS you have two easy options, the Add delimited text layer plug-in or the XY tool plug-in. The next step is to convert your spreadsheet to a point file. For the examples below, I am assuming you have already entered the coordinates in a spreadsheet, and converted to decimal degrees. The easiest way, I think, is to simply enter the coordinates in a spreadsheet, especially if the coordinates come in DM (degrees and minutes) or in DMS (degrees, minutes and seconds). Note that all plug-ins mentioned below are either part of the QGIS core, or can be downloaded with the plug-in manager.įirst step is to convert those coordinates to a point file. What if you want to view those boundaries in e.g., Google Earth? In other words, how to create a polygon layer based on point coordinates? Let’s explore some ways to do this in QGIS. Each polygon was split according to the administrative area.Articles about field studies sometimes (but not always unfortunately) contain coordinates delimiting the boundaries of the field study. With the trace tool activated follow the administrative unit limit.Īt the end you should have three separated polygons. The polygon will be split in 3 parts according to the next image.Ĭlicking on the Trace and Split Features buttons and having the snapping tolerance set we can proceed and split the polygon according to the administrative limits. Lets try a few of these tools and see how they work.įor example if we want to split an polygon (in our case an area represented by a protected area), after a certain limit (a administrative unit limit) we will proceed and use the Split Features tool along with Trace tool. The Advanced digitizing and editing tools enhance the capabilities of QGIS performing operations lik Icon ![]() ![]() Using the basic editing tools you can perform operations like: Icon Go to View > Toolbars > Advanced Digitizing Toolbar. Activate the Advanced Digitizing toolbar.Go to Toggle Editing and start a new edit session.Select the vector you wish to edit by clicking it.In order to start editing a vector layer the next steps are recommended: After you set these parameters you can proceed with your edit process. Make sure you check the Default snap mode to > Vertex and segment.įor Default snapping tolerance and Search radius for vertex edits select a value and from the drop down menu set the values to map units. ![]() In QGIS you can find these options in Settings > Options > Digitizing or in Settings > Snapping Options. This will optimize the editing process of the layers. Before you start a editing session in QGIS, make sure you set the right snapping options ( Snapping Tolerance and Search Radius). Various vector layers and tables (OGR, SpatiaLite, PostGIS, MSSQL Spatial or Oracle Spatial) can be edited in QGIS. Using ESRI products, Carto, Mapbox and Google Mapsįor this exercise please use QGIS version 2.18.
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