Adding New Datasets to QGreenland
Once the QGreenland Core package is downloaded and extracted onto a user’s computer, it
is fully customizable by the user. One can add new data, delete layers within
QGreenland, or make changes. Saving the project will update the
project file. If you do not want to overwrite the original project version, simply save
your updated project using a new filename via Save As… You can create as many
different projects as you like, adding or removing data from the downloaded QGreenland
package or adding data from elsewhere on your computer.
The QGreenland project uses the EPSG:3413 coordinate reference system (CRS) and all pre-loaded layers are either GeoTIFF (raster) or GeoPackage (vector) files. Datasets in different CRSs or data formats can still be added to QGreenland, but may undergo “on the fly reprojection”.
Adding New Layers in QGIS
To add new data layers to QGreenland in QGIS:
In the Menu Bar, go to Layer -> Add Layer, and choose the layer type you want to add. Alternatively, you can either click on the desired add layer button in the toolbar, or click on the Data Source Manager button in the Data Source Manager toolbar.
Any option you choose will open the same Data Source Manager window. On the right side of the window, you can double check that the layer type you want to add is highlighted.
Navigate to the data file that you want to add as a layer, then click Add.
To learn about adding online-access layers (e.g, WMS, WFS, WCS), see our documentaiton on How to add an online layer to QGIS.
Selecting for Greenland-Specific Vector Data
Because the geographic extent of some QGreenland data layers extends beyond the geographic and political border of Greenland to include the surrounding water bodies and land masses, it might sometimes be necessary to filter out certain data if one is only interested in data within Greenland’s geographic boundary. You can do this using the “Greenland coastlines 2017” polygon layer.
To filter for data inside of Greenland:
Make sure that the group you want the filtered/extracted data to be added to is selected/highlighted in the Layers Panel.
Open the Processing Toolbox and go to Vector selection -> Extract by location.
Fill in the following parameters:
Extract features from = the data layer you want to filter, for example, Ice cores
Where the features (geometric predicate) = are within (you can also check intersect and others to capture data that might be located along the Greenland coastline)
By comparing to the features from = Greenland coastlines 2017
Extracted (location) = You can either save the file output from this as a temporary layer or as a permanent layer somewhere on your computer or within your QGreenland data package. Note: If you try to save the file as a GeoPackage layer (GPKG) and receive an error, try again and save it as a Shapefile (SHP) instead.
Click Run and close the window.
The filtered data will show up in the Layers Panel within the group you had selected and likely named Extracted (location). You can rename the layer by right clicking on it and selecting Rename Layer.
Editing Vector Data Layers
How do you add or delete points, line segments, or polygons to/in an existing vector layer in your QGreenland project?
To edit a vector layer:
Select the layer you want to edit in the Layers Panel (click on it so that it is highlighted).
Toggle into editing mode by either right clicking on the vector layer you are editing in the Layers Panel and selecting Toggle Editing or by clicking on the Toggle Editing button in the Digitizing toolbar.
With Editing on, you will have access to new editing buttons in the Digitizing toolbar:
Add new points to a point vector layer
Add new lines to a line vector layer
Add new polygons to a polygon vector layer
Whenever you create any new vector feature, you will be prompted to enter attribute information for the new feature for its record in the layer’s Attribute Table.
If you just want to edit a record in a vector layer’s Attribute Table, you can open the Attribute Table and click on the Toggle Editing icon in the table toolbar. Be sure to save the layer edits after you are done making edits.
When you’re finished, click on the Toggle Editing button again in the toolbar to disable editing.
Creating New Vector Layers from Scratch
In your QGreenland project, you may want to create a new vector layer from scratch, such as a point layer of potential study sites for for your research in Greenland.
To draw a new vector layer from scratch, use the Layer -> Create Layer menu and select one of the following options:
New GeoPackage Layer (reccomended)
New Shapefile Layer (not reccomended, see switchfromshapefile.org).
New Spatiallite Layer
New Temporary Scratch Layer (will not persist data to disk!)
In the new window that opens after selecting one of these options, fill out the given options (each will be slightly different). For detailed instructions on how to add vector layers, see the QGIS documentation.
Creating a GeoPackage layer
In the Menu Bar, go to Layer -> Create Layer -> New GeoPackage Layer or click on the New GeoPackage Layer button in the Data Source Manager toolbar.
A GeoPackage is a GIS file format that allows you to save multiple layers in one file; thus, you will actually be creating a new GeoPackage database that your new GeoPackage layer will live in. In the new window:
Name your new Database
Name the new GeoPackage layer you are creating - this is the Table name
Specify the geometry of the new GeoPackage layer (point, line, etc.)
Specify the layer coordinate reference system
Create the fields that will be in the layer’s Attribute Table by giving them a name and indicating their type (text data, integer, etc.) under New Field. When you click on Add to Fields List, the new field will show up in the Fields List box.
Click Ok. Your new layer will appear in the Layers panel. If it is within another Group you do not want it in, right click on it and select Move Out of Group. You can also drag and drop your layer into the location you want it.
Creating a Custom Clipping Boundary Polygon
You can create your own custom boundary polygon layer to extract features from. Follow the instructions above on Creating New Vector Layers from Scratch to draw a polygon layer from scratch. Then, follow the instructions on Selecting for Greenland-Specific Vector Data to extract features from vector layers using the custom polygon boundary layer instead of the “Greenland coastlines 2017” layer.
Importing GPS and other GNSS Data
QGIS supports importing Global Positioning System (GPS) and other Global Navigation Satellite System (GNSS) data from GPS Exchange Format (GPX) datasets. In the Menu Bar, go to Layer -> Add Layer -> Add GPX Layer.
QGIS can also interface with a GPS device to download data directly and provide live tracking.
Please see the QGIS documentation on Working with GPS Data for more information.