How to contribute new layers
We cannot promise that your layer will be added, so please open an issue and start a discussion before developing a processing pipeline for a new layer.
It is recommended to use the CLI to create a dataset and/or layer template to
help you along. In the below commands, replace filenames, paths, and ids with
real ones. NOTE: When generating templates, but not when fetching, you can
./scripts/experimental/local_cli.sh config-template <dataset|layer> in
place of the
Add a dataset
If the layer does not use an existing dataset, start with a new dataset.
./scripts/cli.sh config-template dataset > \ qgreenland/config/datasets/new_dataset.py
After running the command above, a new_dataset.py file will be populated with dataset information that is needed to create a layer. Make sure that the abstract and title are filled out.
Fetch the data
Once you are finished filling in the dataset information, you can try testing the dataset by fetching the data:
./scripts/cli.sh fetch new_dataset_id
If your fetch command results in an error, there may be issues with the entry of your dataset. Go back to your dataset.py file and make sure that all fields are filled in (abstract, title, etc.) to avoid linting errors.
Create new layer
The next step is to create the new data layer. To do this, create new layer directories as needed, and then define your new layer in a Python file with a descriptive name within the appropriate layer group.
You can do this by running this command:
./scripts/cli.sh config-template layer > \ qgreenland/config/layers/Group/Subgroup/new_layer.py
The above command generates a new_layer.py file. Once you see this file, follow the documentation within the file to fill out your layer configuration.
If the group directory where you have created your layer file has a settings.py file, you must add your new group to the ‘order’ list of this file. Make sure it is spelled exactly the same as in your file structure.
In order for a new dataset to be added to QGreenland, we strongly encourage public archival with OGC-compliant metadata. If data is not publicly archived or stored in a non-standard format, maintenance of that layer takes an order of magnitude more effort and therefore we are unable to promise permanent inclusion of such data. File formats that are particularly challenging include: raw binary grids, Excel files, Word documents. We prefer GeoTIFFs or NetCDFs for raster data, and GeoPackages or shapefiles for vector data.
A correct QGreenland data pipeline will output data that:
Is in EPSG:3413. This is to reduce load on QGIS caused by on-the-fly reprojection. Some exceptions may exist in the current code as a workaround, but they are bugs.
Is subset to one of the defined layer boundaries in
config/project.py. Existing layer tasks can do this for vector or raster data.
For raster data:
In GeoTIFF (
Includes overviews, for raster data. This improves QGIS performance.
Is losslessly compressed using the DEFLATE algorithm.
For vector data:
In GeoPackage (
labelattribute name for pre-calculated labels when using generic styles with labels, for example
Layer quality checklist
Layer descriptions populated
Layer description excludes data provider
Layers’/groups’ title follows date standard: If a layer is date-specific, the date should be the last part of the title except the resolution, if present. Not in parentheses or otherwise distinguished from the rest of the title. Format is “Month DD YYYY” (all fields optional), e.g.:
Common Murre Colonies 2010
Sea Ice Age September 17-24 2010
Layers’/groups’ title follows capitalization standard: Capitalize first letter of the Title. Other than this, only capitalize proper nouns and acronyms. E.g.:
Thickbilled Murre 1km breeding zone
Layers’/groups’ title excludes data provider: Layer should not include provider e.g. “NSIDC”. Put this in the dataset citation instead! EXCEPTION: In some cases, we have the same type of data from various providers, e.g.:
No fields are populated with “TBD” or “TODO”
All layers have style
Any known issues with data quality are listed in “Description”: This should not include spatial mismatch issues, this is covered by our Disclaimer.
Datastore’s data is the latest: Some layers get updated perioidically e.g., earthquakes.
Layers not in unneccessary group
Stakeholders approve citation
Stakeholders approve description
When reprojecting (e.g. via
gdalwarpor adding overviews (e.g. via
gdaladdo), ensure the interpolation algorithm follows standard:
Bilinear for continuous values (i.e. real), e.g. temperatures, height. By default, everything is bilinear.
Nearest neighbor for discrete (i.e. integer) values, e.g. population.
Grid resolution in layer title or group (incl. units), e.g.
My layer (1km)
When a layer is reprojected (e.g., via
gdalwarp), ensure that the target resolution is explicitly specified. Sometimes when the output resolution is not defined, GDAL will choose a resolution that is not appropriate for the data, and this can lead to artifacts.
Polygon labels inside polygons
All attributes have reasonable types (e.g,. a
populationattribute should be an integer type, not string)