Lines, Points, and Polygons
Ok, we've got a background map, now what about vector data?
Adding vector data depends on what kind of format your data is in. Let's run through the standard three types.
To add CSV data to the map, go to Layer-->Add Layer --> Add Delimited Text Layer
Here I've selected a csv of all the places mentioned in a Jesuit Catalogue (about 30000)
And there you go!
Shapefiles are a very common file type for individaul spatial data layers and can be downloaded from spatial database sites like BostonMaps. To import a shapefile into QGIS:
1) Go to Layers-->Add Layer-->Vector Layer
2) Select your ZIPPED folder containing your shapefile as the file to be imported, and click Add!
And your shapefile (in this case polygons representing the open, public spaces of Boston, is added to the map!
GeoJson files are imported the same way as Shapefiles, though no need to zip since its just one file!
Up to now, we've been adding other people's data, or data we have generated in a spreadsheet....what if we want to creat our own data from scratch inside QGIS?
Instead of Adding a Layer, we Create a new one!
When making a new vector layer from scratch, you define its type and attributes similar to how you would in a spreadsheet.
Here I've created a Point shapefile called "Cities". To start adding to it, I just right-click and toggle editing on!
When editing is on, the small editing toolbar will become accessible
From left to right the tools are:
Current Edits allows you to manage your editing session. Here you can save and rollback edits for one or more selected layers.
Toggle Editing provides an additional means of beginning or ending an editing session for a selected layer.
Save Layer Edits allows you to save edits for the selected layer(s) during an editing session.
The Add Features tool will change to the appropriate geometry depending on whether a point, line or polygon layer is selected. Points and vertices of lines and polygons are created by left clicking. To complete a line or polygon feature right click. After adding a feature you will be prompted to enter the attributes.
Features can be moved with the Move Tool by clicking them and dragging them to the new position. Individual feature vertices can be moved with the Node Tool. Click on a feature once with the tool to select it, the vertices will change to red boxes. Click again on an individual vertex to select it. The selected vertex will turn to a dark blue box. From there the vertex can be moved to the desired location. Additionally, edges between vertices can be selected and moved. To add vertices to a feature, simply double click on the edge where you want the vertex to be added. Selected vertices can be deleted by clicking the Delete key on the keyboard. Features can be deleted, cut, copied and pasted with the Delete Selected, Cut Features, Copy Features, and Paste Features.
After clicking to create a new Feature, a box to fill in the attributes you've chosen will appear. Below are the attributes for my pretend Cities shapefile.
You can access and edit all the attributes from your current shapefile by right clicking the name of your layer and selecting Open Attribute Table.
