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The overall concept is the same for both EFAS and GloFAS river networks. Explain that we cannot trust that the location of a station in the model is completely representative of the station location in the 'real world'. Therefore, stations will have to be mapped manually using the following method....
Are there any differences in the remapping process for EFAS & GloFAS? Which information can be merged into a general description? Examples for EFAS & GloFAS?
- A lot of terms are duplicated on these pages: GloFAS mapping locations onto the river network & Mapping locations onto the GloFAS river network . Karen O'Regan combined and updated page.
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As we cannot trust that the location of a station in the model is completely representative of the location of the station in the 'real world' (based off provided coordinates alone), the following protocol to map the stations on the river network should be followed. The overall concept of mapping locations onto the river
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networks is the same for both EFAS and GloFAS
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This page describes the protocol of mapping new locations onto the river network, using the example of GloFAS. In this context, ‘new locations’ are usually river discharge observation stations provided by GloFAS users. The locations represent the catchment of the river at their outlet points. During the process of mapping, the ‘best-fit’ of location in the GloFAS model corresponds with the location of the station on the river in the ‘real world’, based on the coordinates of the station from the data provider.
Users should rely on this protocol as a guideline in case they have to extract point time series. To extract point time series, the locations must be mapped onto the GloFAS river networknetwor.
Tools to use
- Google Earth or Google Maps (to verify the station metadata).
- High detail vector river shapefile (e.g. hydroSHEDS at https://hydrosheds.cr.usgs.gov/datadownload.php or http://gaia.geosci.unc.edu/rivers/
- GloFAS river network, represented by the upstream area map (https://cds.climate.copernicus.eu/cdsapp#!/dataset/cems-glofas-historical?tab=form)
- GIS software to display shapefiles and maps (e.g. QGIS at https://www.qgis.org/en/site/forusers/index.html)
- A good enhancement could be to use maps (e.g. Bing or satellite maps) in QGIS. This would provide a more complete workspace in QGIS with the real maps, the high-resolution river layer, and the GloFAS river network in one space overlayed onto each other. Steps to achieve this in QGIS-3:
- Go to Settings/Options/Network and click on "Use proxy for web access".
- Go to plugins and choose QuickMapServices and click install.
- Maps will be available in the Web tab
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- Make sure the station metadata is correctly provided, identify if any metadata are missing. These should be provided geographic coordinates (lat/lon in degrees), station and river names, and upstream area (if available).
- Search for the station location on Google Maps or Google Earth
- Download the GloFAS upstream area map and load it into QGIS or some other GIS software. It can also be useful be helpful to add a high detail vector river shapefile which can help identifying to identify the real rivers. Alternatively, you can also load the Google Maps/Earth into the GIS software and analyse all layers together.
- Analyse the location of the stations with the other provided metadata and check if they appear to match with the maplocation in Google Earth/Maps.
- Check how the user-provided metadata compares with the maps and the GloFAS river network (represented by the upstream area map). Analyse the upstream area values of the GloFAS river network in the vicinity of the provided river point location.
- This step is a manual, subjective process.
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