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Home > 2. Marine GIS

2. Marine GIS Operations and Tools

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Software:  The MDL Geographic Information System (GIS) exercises are based on the Free and Open Source Software (FOSS) program Saga.  You could use just about any GIS program, because they have many common concepts and features.  I like Saga because it has so many easily accessible features, and it has a very dedicated working group keeping it fixed and updated.

General:  This series of exercises includes all the basic tools for making maps of marine and coastal areas, using existing datafiles (vector or grid) or new ones made by you.  It begins with the assumption that an Area of Interest (AOI) is already known.  If you are not certain of your exact AOI, then begin these exercises with a very large area, say 3 times as wide (in longitude) and 3 times as tall (in latitude) as your first general guess for the AOI.  After a bit of experience, you'll decide on a final (smaller) AOI.  If you are working in a group project, then carefully make a joint decision.

Related Exercises:

• 5 Gridding Marine Data and Handling Grid Products - Separate Saga exercise group

• 5.3 Resampling Grid Data to the Project Map Extent with a "Dummy" Grid - Most frequently used grid exercise

• 9.12 Converting Rasters and Vectors to Google Earth Images, using IDV

Exercises in this Group:

Basic Mapping, Adding Shapes to Maps, Managing Shapes, Adding Grids/Rasters to Maps, Managing Grids/Rasters

Sometime during 2015 an amazing upgrade appeared at Ocean Color Web (OCW):  the data delivery format has changed from HDF to NetCDF.  This makes  exercises 2.21, 2.22 and 2.36 completely out of date, among others, and the necessary updates have been made within this Group.  If you obtain data from OCW, then you can use any of the direct, easy methods for NetCDF import into Saga, Integrated Data Viewer, ncBrowse or Panoply.

Basic Mapping

• 2.1 Saga Preliminary Setup*

  • MAP and DATA settings for best performance

• 2.2 MDL Exercises Project Area*

  • Introduces area polygon (Liberia) for class exercises

  • Uses -180º to +180º mapping schema

• 2.3 Creating a Project Map in Saga*

  • Load "World Borders" low resolution polygon shape for basic map

  • Showing and saving map "projects"

  • Exporting shapefiles to KML vector format

• 2.4 Creating Map Frames in Saga

  • Create line shape and polygon shape of map area

  • Graticules removed here; see new exercise 2.40

  • 2.4.1 Accuracy Check for AOI Frames - Quick check of student progress

• 2.5 Creating Grid Templates in Saga*

  • Create series of grids for the project area, at various "standard" cell-sizes

  • 2.5.1 Accuracy Check for Grid Templates

• 2.13 Creating a 0-360˚ Map System in Saga for Pacific- and Indian-Centered Analyses & Products*

  • Create a project map with 0º to 360º mapping schema

• 2.39 Setting Properties for Multiple Grids/Shapes in Saga

  • Simultaneous setting of display properties

Adding Shapes to Maps

• 2.6 Adding GEBCO Depth Contours to a Project Map in Saga

  • Display and save line shapes of depth contours from GEBCO DVD or from GEBCO-Lite

  • Load and display (color coded) contours in project map

  • 2.6.1 Accuracy Check for GEBCO Depth Contours

• 2.8 Adding Administrative Boundaries and Coastline to a Project Map in Saga

  • Browse, select and download useful shapefiles for map enhancements

• 2.9 Global Collection of Boundaries and Named Zones Data for Marine GIS:  VLIZ MarineRegions

  • Browse, select and download useful shapefiles of marine "boundaries" for map enhancements

  • Named places and features are now covered by Exercise 2.37, below

• 2.10 Adding a Text-Dominated Spreadsheet to a Project Map in Saga

• 2.11 Adding a Number-Dominated Spreadsheet to a Project Map in Saga

• 2.29 Adding Navigation Charts to Maps in Saga: KAP, BSB, S-57

  • Chart files are located from global vendors or free sources

  • Grid versions are reprojected with special free software and loaded as georeferenced images

  • Vector versions are directly loaded into shape assemblies

• 2.33 Managing Global Coastline, River and Lake Vectors: GSHHG
  • Install the GSHHG global files; then install the GEODAS-NG software
  • Extract shores and rivers (as shapes) for Liberia
  • Note the alternate method for extracting special XY0 text files for use in gridding relief data
• 2.35 Managing & Visualizing MGD77 and XYZ Geologic Survey Data in Saga: NGDC
  • Browse and obtain survey data from a new web interface
  • Download simple ASCII tables for direct management and display in Saga
  • Relations with GEBCO are discussed
• 2.37 Global Gazetteer of Named Marine Places and Features for Marine GIS:  GeoNET Names Server

• 2.40 Adding Graticules to Saga Maps

  • Uses the new top-level Graticules function instead of the older Tool

• 2.41 Adding Global Imagery to Maps in Saga

Managing Shapes

• 2.12 Cutting a Shape to the Project Map Extent in Saga*

  • Use appropriate frame shape to cut point shape, line shape or polygon shape down to desired size

  • 2.12 Accuracy Check for Shape Cutting

• 2.15 Creating a New Shape in Saga from Published Coordinates*

  • Load table of coordinates into a module that creates a shapefile

• 2.20 Removing "Land Stations" from a Marine Data Collection*

  • Merge world borders polygons with point shape of stations to reveal country codes for points, i.e. points on land

• 2.26 Digitizing High-Resolution Borders and Coastlines in Google Earth*

  • Browse Google Earth (GE) images down to smallest local image

  • Digitize salient points along land-water margins

  • Save KML files for use with GE or Saga

• 2.27 Reprojecting Vector Data in Saga:  UTM to WGS84*

  • If necessary, convert data table to a point shape

  • Specify the current projection of the shape, and save it for security

  • Specify the new projection to apply

  • Save the new shape, appropriately named to indicate re-projection

• 2.28 Reprojecting Grid Data in Saga:  WGS84 to UTM

  • Specify the current projection of the grid, and save it for security

  • Specify the new projection to apply

  • Save the new grid, appropriately re-named to indicate re-projection

Adding Grids/Rasters to Maps

• 2.7 Adding a Sediment Thickness Grid to a Project Map in Saga*

  • Locate and download global grid

  • Convert grid to -180º to +180º system (with 2.13)

  • Load and display grid on project map

• 2.18 Discontinued US Navy Marine Atlas: Global Wave Grids*

  • Examine and find ASCII headers leading raw binary grids

  • Use header information to load grids

  • Use basic examination to find and use blanking and Z-factor information

  • Compare with 2.32, below

• 2.19 Visualizing Climatological Grid Analyses in IDV: THREDDS*

  • General methods to find and use typical grids (format irrelevant)

• 2.21 Importing NetCDF Satellite T, S, and Chlorophyll Climatological or Operational Grids into Marine GIS: OceanColor Web

  • Uses data from Exercise 2.36

  • Uses new NetCDF and HDF5 global rasters from OCW

  • All methodology now combined into single metholodology, including descaling

• 2.22 Importing "Scaled" HDF Satellite Surface Temperature Climatologies into Marine GIS: OceanColor Web*

  • Deprecated; please refer to 2.21, above

• 2.24 Visualizing High-Density/Small Coastal Area Environmental Survey Data in Saga

  • Load and grid a typical spreadsheet file of station data

  • Use high-resolution shoreline file (made with Exercise 2.26, above) to create a "water polygon"

  • Use water polygon to clip data grid to show only at-sea values

• 2.25 Visualizing a NetCDF Grid with Not-a-Number (NaN) Values in Saga

  • NaN values sometimes occur in NetCDF grids; until Saga is revised to handle them, use this method to recognize and omit them from visualizations

• 2.29 Adding Navigation Charts to Maps in Saga: KAP, BSB, S-57

  • Chart files are located from global vendors or free sources

  • Grid versions are reprojected with special free software and loaded as georeferenced images

  • Vector versions are directly loaded into shape assemblies

• 2.30 Adding UCSD/Scripps Mixed Layer Depths Climatology to Maps in Saga:  Argo

  • Find and load desired products from a wide range of surface layer products

  • Make corrections to the coordinate system

  • Subset and display MDL products for Liberia

• 2.31 Importing Satellite SST and Sea Ice Climatologies into Marine GIS: NCEI LAS

  • Obtain regionally subsetted data for any year-day from a standard Live Access Server

  • NetCDF downloads require careful examination in Saga to select the best display tool

• 2.32 Global Wave Grids from the EU Climatology

  • Explore the data product website and download appropriate data for your purposes

  • Perform necessary edits and conversions on the data for use in Saga

  • Visualize the data in Saga, appropriately displayed, and produce statistical tables

  • Compare to 2.18, above

• 2.34 Visualizing Altimeter and SAR Global Wave Data Grids (L4) in Saga:  GlobWave

  • Obtain and display climatological wave-height analyses

• 2.36 Obtaining Operational & Climatological Satellite Temperature, Salinity, and Chlorophyll Ocean Data: OceanColor Web

  • Identify and download high-quality monthly climatologies for T, S and Chlorophyll, in preparation for other exercises that use these data in GIS

  • Use these data in Exercise 2.21

• 2.38 Obtaining Satellite Chlorophyll-a Imagery from Giovanni

  • Deprecated in favor of 2.21 Importing NetCDF Satellite T, S, and Chlorophyll Climatological or Operational Grids into Marine GIS: OceanColor Web

• 2.41 Adding Global Imagery to Maps in Saga

Managing Grids/Rasters - All have been moved to 5. Gridding Marine Data & Handling Grid Products

• Using Grid Statistics and Calculations for Ecological Assessments in Saga

• Converting Between 0-to-360 Degree Grids and -180-to-180 Degree Grids in Saga

• Managing NetCDF, HDF4/5 and GRIB Rasters with Principal Display Programs

• Reprojecting Grid Data in Saga:  WGS84 to UTM