Home > 1. Data Basics

1.7 Essential Global Data Layers for Geo Atlases

This list of global data has been prepared for educational purposes only.  It covers climatological but not operational data sources.  Only the atmosphere, cryosphere and hydrosphere data are provided at acceptable scales (compared to intrinsic physical length scales).   All the remaining data are probably not at desirable resolutions for national or local marine resource assessment and management.  Please only consider these datasets for use if no better resources are known.

Version:  11--8-2021

BASE MAP    CRYOSPHERE    GEOSPHERE    HYDROSPHERE    BIOSPHERE    ATMOSPHERE    TECHNOSPHERE

  Spatial, Temporal or Thematic Considerations Original Publisher Current Source Native Format Processing Method and Comments
Dummy Grids for Resampling (necessary auxiliary file) Needed for most global datasets that follow     SGRD Creating Grid Templates in Saga
Graticules Optional (for better map appearance)     SHP Creating Graticules in Saga

NOTE:  For unknown reasons, graticule shapes load very slowly in web mapping systems
Coastline and Land Political Boundaries   SRTM/SWBD DIVA SHP Adding Administrative Boundaries and Coastline to a Project Map in Saga
Global Self-consistent, Hierarchical, High-resolution Geography Database (GSHHG)

(Was GSHHS before addition of WDBii)

     NGDC SHP 2.33 Managing Global Coastline, River and Lake Vectors: GSHHG
Rivers & Lakes   DCW DIVA SHP  
Marine Boundaries & Regions (including EEZ)     Marine Regions SHP Adding Marine Regions to a Project Map in Saga

 
Marine Regions:
  • 25,371 marine georeferenced places
  • 32,484 marine place names
  • 5,595 polygons of geographic places
  • 12 marine geographic regional/global classifications
     Marine Regions [Formerly VLIMAR] SHP Adding Marine Regions to a Project Map in Saga
GEBCO 08 (land & water; combines best bathy sources and SRTM (see below) 1-minute and 30-second versions available; users can work locally with the downloaded global dataset, or perform online geographic subsetting GEBCO BODC "NetCDF" format variant

GEBCO 08 Global Relief Grid: Local Processing, or GEBCO 08 Global Relief Grid:  Online Processing

 

Other applicable exercises:

Estimating Topographic Contours in Saga from SRTM Data

 
Master catalog of nearly all major topography datasets   Various sources Viewfinder Panoramas Mainly HGT

HGT is compatible with Saga's GDAL module
Shuttle Radar Topography Mission (SRTM) 30-second country topography (with/without border mask CGIAR DIVA GRI + GRD + VRT Estimating Topographic Contours in Saga from SRTM Data
Shuttle Radar Topography Mission (SRTM) 3-second/90-m CGIAR      
GEBCO relief contours Selected contours; WVS coastline GEBCO CD ROM SHP Adding GEBCO Depth Contours to a Project Map in Saga 
Gazetteer Selected country   DIVA SHP NOTE:  The preferred practice for land locations would be to source desired place names locally.  When not available, then use the DIVA resource cited here. 
Gazetteer   GEBCO Undersea
Feature Names		 US NGDC   Results from searches can be exported as Excel, CSV or shapefiles.
Undersea Features from GNS   NGA Geonet Names Server TXT Adding a Text-Dominated Spreadsheet to a Project Map in Saga
Metareas for Global Maritime Distress and Safety System (GMDSS)   WMO MarTrans    
Minor Islands (<2 km^2)   Natural Earth Data      
Geographic Lines Tropical and polar circles, equator, and International Date Line. Natural Earth Data      
Single Points at Named Locations   Batch Geocoding [Discovered by Jan Helebrant for Saga users]     To convert addresses or named locations into latitude-longitude coordinate pairs; can handle lists
UNEP Shelf Program maps of Extended Continental Shelf (ECS) proposals collated by GRID-Arendal     GRID-Arendal   Find and view the KML maps in the lower-right corner of the lists.  Just click on any map object to select it and see the available files (very complex collections of points, lines and polygons.)

Download and employ shapefiles in the usual way.   Take care to use only the latest materials and avoid any comments or text that might cause political problems; this subject is very sensitive and the resources are not easy to interpret.
Natural Earth is a public domain map dataset available at 1:10m, 1:50m, and 1:110 million scales     NaturalEarth    
NGDC GLOBE 30-second (1-km)global land relief data     NOAA-NGDC    
UNEP Shelf Program maps of Extended Continental Shelf (ECS) files submitted by member States     GRID-Arendal    
Antarctic Ice Shelves     Natural Earth Data    
Layer Name Spatial, Temporal or Thematic Considerations Original Publisher Current Source Native Format Processing Method and Comments
Earthquakes (events & effects locations)    NGDC   TSV Import table into Saga

In Saga, use SHAPES - POINTS > CONVERT A TABLE TO POINTS to make point shape

Examine the DBF (attributes table) of the remaining point shape to see any magnitude or size attribute would be good to scale the plotted symbols.  Set the appropriate Saga plotting symbol in SETTINGS, then save the settings as an SPRM file
Tsunamis (events & effects locations)   NGDC   TSV Same as earthquakes, above.
Volcanoes   NGDC     Same as earthquakes, above.
Geothermal Energy   NGDC     Same as earthquakes, above.
Mineral Resources Online Spatial Data   USGS (see also parent page for more topics)     Interactive maps and downloadable data for global Geology, Geochemistry, Geophysics, and Mineral Resources
Seafloor Lithology   GPGPlates     Patterns of distribution of sediments in the global ocean.  Uses a 13-class typology.
Sediment Thickness   NGDC   ArcInfo ADF Adding a Sediment Thickness Grid to a Project Map in Saga
Layer Name Spatial, Temporal or Thematic Considerations Original Publisher Current Source Native Format Processing Method and Comments
High-Resolution Sea surface temperature - MODIS Surface AquaMODIS Ocean Color Web (Level 3) HDF Importing Unprojected HDF Satellite Imagery (L3/L4) into Marine GIS (for SST data)
High-Resolution Chlorophyll   SeaWIFS Ocean Color Web (Level 3) HDF Importing Unprojected HDF Satellite Imagery (L3/L4) into Marine GIS (for chlorophyll data)
Temperature, Salinity, Oxygen, Nitrate, Phosphate and Silicate Selected area and depths World Ocean Atlas 2009 IRI/LDEO Climate Data Library ASC Obtaining Standard-Depth Analyzed Parameters from the World Ocean Atlas 2009
Mixed Layer Depths (plus MDL temperatures, salinities, and densities)   Argo Mixed Layers from Scripps/University of California at San Diego   NC 2.30 Adding Argo Mixed Layer Depths to Maps in Saga:  UCSD/Scripps
Marine primary production Seasonal   Rutgers OPPT BIN Download 4 seasons

In Saga, use IMPORT/EXPORT GRIDS > IMPORT BINARY RAW GRID

  • Columns: 2048
  • Rows: 1024
  • Cell Size: 360/2048
  • Left Border:  -179.5 (best fit)
  • Lower Border: -89.5 (best fit)
  • No Data Value: 0
  • Data Type: 4-byte floating point
  • Byte Order:  Big Endian/Motorola
  • Flip, if necessary, using GRID TOOLS > GRID ORIENTATION in Saga. 
Surface current drift Monthly   GDP NetCDF Plotting Vector Arrows from the Global Drifter Program 0.5-Degree Climatology
Tide Component M2   A Global Ocean Tide Model from TOPEX/POSEIDON Altimetry: GOT99.2 See exercise for updated file Text Converting 0-to-360 Degree Grids to -180-to-180 Degree Grids
Waves Monthly US Navy Marine Atlas Raw binary Discontinued US Navy Marine Atlas: Global Wave Grids
Waves Monthly Global Atlas of Ocean Waves - Based on VOS Observations   Text 2.32 Global Wave Grids from the EU Climatology
Optics (including Secchi disk depths)   World Ocean Optics Database     3.5 Obtaining Secchi Disk Depths from the Worldwide Ocean Optics Database (WOOD)
Layer Name Spatial, Temporal or Thematic Considerations Original Publisher Current Source Native Format Processing Method and Comments
Global Species Distribution Records Areal, temporal and taxonomic subsetting   Ocean Biogeographic Information System (OBIS) CSV tables, KML maps, OGC products

3.6 Managing Global Records for One Taxon in OBIS

3.7 Managing/Repatriating Local Records of Multiple Taxa in OBIS

 
Special Areas: mangroves, wetlands, seagrasses, corals, etc. WCMC SHP NOTE:  Source locally if at all possible, because these resources are global and low-resolution
Marine protected areas (MPAs)   World Database of Protected Areas Protected Planet SHP NOTE:  Recent drastic revision seems now to provide local-scale maps for nearly 1000 areas, including >700 "marine" MPAs.

Recent views of MPAs along the South Brazil coast show some possible misplacements of areas, so do some reality checks for all polygons.
Land Cover Classification 30-second GLC2000 DIVA GRD + GRI + VRT In Saga, use IMPORT/EXPORT GDAL > IMPORT RASTER and import the VRT file.  Set number of colors to 21 and display with a preset RAINBOW palette.
Global Land Cover Classification (GLCF)     GLCF/UMD FLT Handling Classified Grids with Saga
Collection of boundaries for political and scientific management of ocean areas (e.g. FAO Fisheries Zones, global science programs, IHO seas (updated), ecological zonation, etc.)     VLIMAR SHP Adding Marine Regions to a Project Map in Saga
Coral Reefs and Atolls   Natural Earth Data      
Coral Reefs Global summary maps of resources and risk categories Millenium Coral Reef Mapping Program Reefs at Risk SHP and KML; grids Cutting a Shape to the Project Map Extent in Saga
Layer Name Spatial, Temporal or Thematic Considerations Original Publisher Current Source Native Format Processing Method and Comments
Precipitation, Relative Humidity Marine only; 12 months Atlas of Surface Marine Data 1994 NVODS ASC In NVODS select Atlas of Surface Marine Data 1994

Select Precipitation Rate or Relative Humidity

Select the month and the exact geographic area.  Make sure the geographic coordinates are in the system you want (usually -180 to +180)  Then use SAVE AS > DOWNLOAD DATA in the ESRI ASC format for direct use in Saga
Precipitation Africa only; land and marine;  12months

Africa Rainfall Climatology Ver. 2 (ARC2)

 

 IRI/INGRID > Data Source > Climatology > Monthly Raw BIN CLIMATOLOGY_DATA > MEAN_MONTHLY TOTALS where there are 12 floating binary  files, one for each month (e.g.. clim.month.bin.01, etc)

You can process these in Saga (Import/Export Grids > Import Binary Raw Data).
 
Air temperature Selected area and months COADS Monthly Climatology NVODS ASC Plotting Vector Arrows from U and V Component Grids with Saga (select Air Temperature, but stop at Panel 13)
Wind speed Selected area and months COADS Monthly Climatology NVODS ASC Plotting Vector Arrows from U and V Component Grids with Saga (select Wind Speed, but stop at Panel 13)
Wind vectors Selected area and months COADS Monthly Climatology NVODS ASC Plotting Vector Arrows from U and V Component Grids with Saga (but ignore the shipdrift currents section)
Climate grids (various parameters) monthly; annual extremes; use 10-arc min grids    WorldClim BIL Use Z-Factor of 0.1 in Saga to correct temperatures

NOTE:  The apparent ultra-high resolution in some of these data may be attractive to some, but the basic atmospheric processes do not allow for such short spatial scales for climatological products.
Layer Name Spatial, Temporal or Thematic Considerations Original Publisher Current Source Native Format Processing Method and Comments
Population density   SEDAC NASA NEO GeoTIFF float
  1. In Saga, load GeoTIFF with GDAL raster input module
  2. Reset no-data values to -99999
  3. Use Resampling Grid Data to the Project Map Extent with a "Dummy" Grid to subsample to grid resolution that is just smaller or equal to the original resolution
  4. Save as SGRD with good long filename
  5. Examine histogram to set value range realistically (data unit is persons/km^2)
  6. Use log scale for better viewing

NOTE:  Source locally if at all possible, because this resource is global and low-resolution
Populated Places   Natural Earth Data      
Urban Area Polygons   Natural Earth Data      
Night Time Lights Products (multiple sensors)   NGDC   Various, including GeoTIF  
Roads   DCW DIVA SHP  
Railroads   DCW DIVA SHP  
Ports   World Ports Index WPI SHP  
Communications Cables   Greg's Cable Maps GCM SHP, KML  
Time Zones   Natural Earth Data   SHP, GeoTIF Global data are mainly 1:10M