Earth Observation 4 Land Degradation Neutrality — Part 3: guide through the geoportals
The search for usable relevant earth observation data related to land degradation can be a challenging and long process. In our previous blog post the different characteristics of earth observation data were explained. Once it is clear what data characteristics are needed in a specific project, the search for the data can start! Datasets are mostly scattered across different institutes and agencies. Luckily some relevant and frequently used datasets are stored in geoportals. Esri’s definition of a geoportal is:
“A portal is a Web-accessible catalog that enables the posting, discovery, and exchange of information resources”. — Esri
Some countries have their own geoportals while others depend on global data. A list of countries with their own geoportal can be found here. The biggest and easiest to use global geoportals e.g. GEOSS, global forest watch, resource watch are discussed in this blog post. There are some difference between the global geoportals. For example some geoportals contain earth observation data that is already translated into information while other portals contain datasets that still need some processing (see blog post 2 in the series Earth Observation 4 Land Degradation Neutrality about data processing levels). Another difference is the amount of topics covered by the available datasets. Some geoportals are focused on a specific topic while others store geodata about any available topic.
Disclaimer: this is only a selection of relevant geoportals not a complete overview.
GEOSS portal
The Global Earth Observation System of Systems (GEOSS) is one of the bigger geoportals build by the European Space Agency (ESA) and the Group on Earth Observations (GEO). The main aim of the GEOSS portal is sharing open earth observation data for end users working on environmental challenges. Datasets shared on the GEOSS platform are (i) accessible, (ii) have an identified quality (iii) the source of the dataset is known and (iv) the data is interoperable. The platform currently combines a large amount of datasets from more than 150 separate catalogs and information systems e.g. GBIF, Data.gov, NASA, ESA, NOAA click here for the complete list. The GEOSS portal is fairly easy to use (see Youtube video below) with the option to limit the searches on temporal resolution, thematic information and geographic location. Both low level earth observation data and processed data are available on the GEOSS portal, this means that some knowledge into the different characteristics of data is needed (see blog 2 in the series Earth Observation 4 Land Degradation Neutrality). Every datasets contains information about the geographical coverage, spatial coverage, data format and a download link.
The portal does not contain information about a specific topic but stores every possible earth observation dataset shared by their partners. This is both an advantage and a disadvantage. An advantage because it provides one easily accessible internet portal for all topics, but a disadvantage because you need specific keywords to find the right dataset. Another disadvantage of the portal is that some expertise into the field of earth observation is needed, the data cannot be viewed or accessed in the portal itself, this means that a GIS software environment is needed.
World Resource Institute
The world resource institute (WRI) is a global research institute that works on sustaining our natural resources. The research institute has offices in more than 50 countries working on six issues related to energy, climate, cities and transport, forest, food and water. The spatial data used and produced in their research is shared with users in the public and private sector to induce action. The WRI offers multiple data platforms and e.g. the resource watch, climate watch, PREPData and the global forest watch. Because of the variety of geoportals offered only the WRI geoportals relevant to land degradation are discussed below.
- Global Forest Watch
The Global Forest Watch (GFW) is an initiative of the World Resource Institute and is used very often. The main strength of the GFW is that it offers an open-source internet portal to monitor and analyse forest ecosystems worldwide in near real-time. The portal combines more than a 100 forest related datasets that contain information about e.g. forest cover, forest fires and palm oil mills. The design of the portal makes it easy for a wide variety of users (governments, NGOs, journalists, students and researchers) to access information on a small scale or a global scale on forest landscapes. The geoportal is focused on providing information for decision making and action. It is even possible to set alerts that can be received per email when an area of interest is changed due to deforestation or forest fires. The user interface of the GFW portal is easy to use and all the datasets can be viewed in the data viewer (see Youtube video below).
The main advantage of the GFW is that raw satellite imagery is already translated into usable information offering earth observation novices access to near real-time information on forest ecosystems. The portal contains five information categories: forest change, land cover, land use, climate and biodiversity. All the datasets within the five categories contain metadata with the source of the datasets, frequency of updates, coverage and a short explanation. It is also possible to calculate the percentage of tree cover loss, tree cover gain and biomass for an area of interest within the GFW portal itself. This has as an advantage that you do not need the skills to download the data and analyze it in a GIS software environment.
2. Resource watch
The Resource Watch is also an initiative of the World Resource Institute and focuses on providing datasets that are relevant for a sustainable future. Together with more than 30 partners the world resource institute launched the Resource watch as a central portal to remotely access datasets from different sources. All the offered datasets are open, free and can be downloaded. The main advantage of the portal is that it interconnects multiple datasets offering a quick instrument to identify the link between different problems. Users can overlay and explore datasets easily in the resource watch data explorer (see youtube video below). The portal contains hundreds of datasets clustered in the following topics: cities, climate, energy, food, forests, society, oceans and water. The importance of each topic is explained and some examples of the use of the offered data is given.
The Resource Watch platform offers a few extra possibilities to view and use the available datasets. For example the possibility to view near-real time data on the planet pulse viewer. The planet pulse viewer shows the most recent datasets about forest clearing, floods, ozone, arctic sea ice, migration deaths or landslide warnings. It is also possible to sign up for alerts by email to track floods, earthquakes or fires in a specific area. The data can also be used to create a custom dashboard to show for example the land cover change in Ethiopia over the past 10 years. Custom maps, timeseries, and graphs can be added and created in the dashboards. An example of a dashboard can be found here.
The main advantage of the Resource watch is that the portal offers the possibility to overlay multiple dataset for a wide variety of topics. Little knowledge about geodata is needed to extract relevant information and even link datasets. No GIS software environments are needed to create esthetically appealing maps. It is easy to build a story around the offered information in the custom dashboards. When the data is needed for further analysis and calculations it can be accessed via the download link in the metadata section.
WaPOR
The Water Productivity Open Access Portal (WaPOR) is a geoportal developed by the Food and Agricultural Organization (FAO). The main aim of the portal is to use earth observation data to monitor water productivity in Africa and the Near East. This is of importance because, due to climate change and demographic growth, it becomes more challenging to achieve food security for all while sustainably using our water resources. The WaPOR offers the opportunity to view and analyze water productivity data in the portal itself to assist decision makers in the agricultural sector. It is possible to analyze data through time, identify anomalies and calculate statistics from 2009 onwards. Examples of datasets that can be viewed and analyzed in the WaPOR are: precipitation, primary production, land cover, land surface temperatures and gross biomass water productivity.
The main advantage of the WaPOR is that the data is easily accessible for geodata novices. All the datasets that are of importance to monitor water productivity are clustered in one portal reducing search times. The data can easily be analyzed in the portal itself for a specific area of interest meaning that no GIS software environments are needed. A disadvantage of the WaPOR is that the portal only contains information about Africa and the Near East.
Worldview
The Worldview geoportal is constructed by NASA and gives an overview of changes on earth derived from multiple satellite sensors between 2000-present. The platform offers the ability to rapidly access, view and download imagery. Before the construction of the platform it was a time consuming exercise to download and view the imagery, now it is possible to simple browse through all the imagery. The baseline imagery are from the MODIS sensors aboard the Terra and Aqua satellites. However, hundreds of additional datasets can be added to the MODIS data e.g. settlements, boundaries, ice, NDVI, land surface temperature, fires and air quality. Changes through time can be visualized in exportable GIF animations. It is also possible to follow current natural events such as volcanic eruptions, tropical storms, fires and track the movements of icebergs.
An advantage of the Worldview portal is the user interface and the integration of hundreds of datasets. It is easy to use, view and download the data to track spatial phenomenon’s for an area of interest. However, careful consideration is needed when adding additional datasets to the MODIS imagery because not all datasets cover the same time interval. For example it is possible to overlay MODIS 2002 imagery with a population density map of 2015.
Sentinel Hub
The Sentinel Hub is constructed by ESA and contains satellite imagery from the Sentinels, Landsat, Envisat Meris, MODIS, Proba-V and GIBS. The portal offers the opportunity to visually inspect the datasets but also to combine the different datasets. There are various visualization options available such as false color composites, NDVI, moisture index, NDWI, SWIT and true color composites. Custom combinations between bands and data processing are possible within the portal giving the opportunity to calculate specific indices or classifications. Once the satellite sensor and visualization is chosen it is possible to construct time series (graph and GIF animation) for an area or location. For further analysis the datasets can directly be downloaded from the portal in a GeoTIFF, kml or JP2 format.
The main advantage of the Sentinel Hub is that the portal serves both earth observation experts and novices. Preselected indices can be calculated but it is also possible to combine other bands with custom scripts. A disadvantage of the portal is that some knowledge about the sensors is needed. Only the names of the sensors are mentioned but it is unclear for novices what information these sensors gather.
Tutorial and reading tips
- Blog post from the Radiant Earth Foundation about the role governmental open satellite datasets have in global developments.
- Deltares the institute for applied research listed relevant portals in the field of climate and weather, elevation, satellite imagery, marine, geology and general data portals.
- Webinar about NASA’s worldview.
