L. Build your own Shelf (UNCLOS) Project

Owned by Harald Sund (Unlicensed)
Last updated: May 16, 2018 by Jon Mugaas
12 min read

Introduction

We have now been through all the main steps in building a Shelf project, and it is time to look at a real example. In this section we are going to build a project from scratch in an area you want to look closer at. We are going to use public data available online or provided by us, analyze them and generating the datasets we needed for a submission. The first part of this section will mainly be about importing data and converting it to the correct projection. In the last part we will produce the distance lines, analyze the bathymetry, generate Hedberg points and Gardiner points and hopefully produce an outer limit.

Exercises

The UNCLOS Project Template

Geocap provide empty folder structure for various types of projects. This will give you a starting point to get organized with your own project. A project template either gives you a ready made folder structure, or it gives you a suite of folders to choose from.

An empty project structure may be used for communicating relevant data to colleagues, or for analysis and trouble shooting by us. To send parts of a project to us in Geocap Support, even only a single dataset, you may copy the dataset (or a folder) from your main project and paste it into this empty project. Then zip and send the disk folder projectname.zip to support@geocap.no

Geocap can provide an empty folder structure for UNCLOS projects. This will give you a starting point to get organized with your own UNCLOS project. The default folder structure holds empty folders for most of the data types you will need. If you do not find a suitable folder you can create a new folder for that data. It is also a good idea to create sub-folders if you have a lot of data, for example a sub-folder for each survey or for each region. Other subfolders commonly created are folders for FOS Collections, Images etc.


Exercise

Generate a new and empty UNCLOS project

  • In the main menu, click File > New > Project.
  • Select UNCLOS project template.
  • In the Name field type in Geocap_Training_<Year> . Project names may consist of letters, numbers and spaces, but special characters like [, æ,ø, å, &, /, % ... should be avoided.
  • Click the Browse button, and select where you want to store your project on your hard disk.
  • Click Finish.


An empty Shelf project

The idea is that this basic structure is kept. Folders may be added and data imported, but the original folders should not be renamed or moved, and their schemas should not be changed. This is because this folder structure is used when new datasets are generated. If an original folder is not present, it will be recreated.

Import Data

We will now explain the basics of importing datasets and working with coordinate systems in Geocap. Most datasets in Geocap are imported using the ASCII import or the Generic import. The Generic import is used to import a number of different formats, such as images, grids, shapefiles etc. When browsing in a file, the Generic import will recognize the file format and let you define an Area of Interest to import. The ASCII import reads data from an ASCII file into the Geocap project. ASCII import can be used for many types text data files, e.g. whether the data columns have fixed or variable width, and also whether the coordinates are in X Y or Lat Lon. When data is read into the project, it can be organized in a number of different ways. It is for example possible to tell Geocap to split the data into different dataset whenever a value in a specific file column changes. There are also options for creating project folders whenever a column value changes.

We have already used the ASCII import in a previous section so in this section we are going to import different datasets using the Generic import method and convert the datasets to the projection we want to use in our project.


Coastline

We are now going to import a coastline file. National Geophysical Data Center (NGDC) provides coast lines covering the entire world in a data set they call GSHHS (Global Self-consistent, Hierarchical, High-resolution Shoreline Database). Geocap can read both the raw data format (the files gshhs_*.b files), and the shapefiles directly. In this exercise we are going to import the *.b files. 

If you have limited internet connection you can skip this exercise and continue with the next one since we have provided the dataset already.

Exercise

Download coastline files from the Internet

  1. Open a web browser and go to this NGDC web page: http://www.ngdc.noaa.gov/mgg/shorelines/gshhs.html.
  2. Click Download GSHHS Data version 2.3.4 (January 1, 2015).
  3. Download and save the file gshhs-bin-2.3.4.zip (09-Mar-2015 11:14 113M).
  4. Uncompress the files to a folder on your hard disk.
Exercise

Import and display the GSHHS coastline files

  1. Locate the folder 1. Maritime Lines/Coast Lines in your Geocap project.

  2. Right click the folder and select Import > Generic….

  3. The format should be set to Automatic.

  4. Click the browse button and locate the folder with the GSHHS files.

  5. Select the file called gshhs_f.b and click Open.
  6. Click the Area of Interest tab.
  7. Check the Import Area check box.
  8. Type in the minimum and maximum latitude and longitude in decimal degrees.
    1. Max Y = Northern boundary of import area Min X = Western boundary of import area.
    2. Max X = Eastern boundary of import area Min Y = Southern boundary of import area.
  9. Click Execute.
  10. Geocap will recognize the datum and coordinate system of the file and confirm that the file has been read. Click OK.
  11. After the file has been read, click the OK button in the Generic reader dialog.
  12. Observe that the imported dataset is stored in the Coast lines folder.
  13. Right click the dataset and select Zoom to Data.
  14. Right click the dataset and select Display.


The data is imported in geographical coordinates with latitude as Y and longitude as X. In order to view the data in a proper projection we convert the data to to the projection we want to use.

Exercise

Convert coast line to the right projection and display

  1. Click the dataset and go to the Shared commands section in the Toolbox.
  2. Double click the Convert to... command you want to use, in the Operations folder.
  3. Define the appropriate settings.
  4. Change the result combo box to Replace input.
  5. Click Execute.
  6. Agree to replace the existing dataset by clicking Yes.
  7. The data is now converted. Click OK.
  8. Click OK to close the conversion menu.
  9. Observe that the display is automatically updated to the new projection.

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Global Seabed Grid

ETOPO1 is a 1 arc-minute global relief model of Earth's surface that integrates land topography and ocean bathymetry. In the next exercises we will download and import this grid into Geocap.

Exercise

Download the ETOPO1 grid from the Internet

  1. Open a web browser, and go to the following address: http://www.ngdc.noaa.gov/mgg/global/global.html.
  2. Click the link: Extract Custom Grids - in the left column on the page, below the globe. A new web page with a interactive map should appear.
  3. Zoom into the area where you want to extract the grid.
  4. Click the icon with and i in the upper left corner of the map window.
  5. Drag a rectangle over the area where you want to extract the grid. You should see a red rectangle on the map.
  6. Keep Layer as ETOPO1 (ice).
  7. Select Output Format GeoTIFF.
  8. Click "click here to download".
Exercise

Import the seabed grid

  1. Locate the folder called Grids in your Geocap project under 2. Seabed.
  2. Right click the folder and select Import > Generic…
  3. The format should be set to Automatic.
  4. Click the browse button and locate the ETOPO file.
  5. In order to import the whole file, make sure the "Specify import area" is not checked
  6. Click on the Reader Options tab. Then under "Poly Data  / Structured Points",  check the box next to Invert (The grid has negative values for sea depths, and positive values for heights above sea level. Usually bathymetry data has positive values for depths. We therefore have to multiply the depth and height values by -1 with this option to "flip" the data).
  7. Click Execute.
  8. You will now be prompted with a question of the coordinate system and datum. Select: World Geodetic system 1984, Geodetic and click OK.
  9. Geocap will report if the grid has been imported correctly; click OK and close the import dialog by clicking Cancel.
  10. Observe that the new data set has appeared in the Grids folder.


The data is imported in Geodetic, with latitudes as Y coordinates and longitudes as X coordinates.  In order to view the grid with the data we have already imported and converted to another projection, we need to convert this grid to match the same projection as the other data in the project .

Exercise

Convert the grid to the right projection and display

  1. Click the seabed grid and go to the Shared commands section in the Toolbox.
  2. Double click the Convert to... command you want to use, in the Operations folder.
  3. Define the appropriate settings
  4. Change the result combo box to Replace input.
  5. Click Execute.
  6. Agree to replace the existing dataset by clicking Yes.
  7. Geocap will report if the grid has been converted correctly, click OK and close the conversion dialog by clicking Cancel.
  8. Check that the schema of the dataset is seabed surface.  If not then right click the dataset, choose Set Schema and choose seabed surface.
  9. Display the dataset together with the coastline.


Global sediment thickness

The Global Sediment thickness can be downloaded as a grid here: http://www.ngdc.noaa.gov/mgg/sedthick/index.html

Exercise

Import the sediment thickness grid

  1. Locate the folder called Grids in your Geocap project under 3. Sediment Data (you might have to create it)
  2. Right click the folder and select Import > Generic…
  3. The format should be set to Automatic.
  4. Click the browse button and locate the sediment thickness file.
  5. Click the Area of Interest tab.
  6. Check the Import Area check box.
  7. Type in the minimum and maximum latitude and longitude in decimal degrees.
    1. Max Y = Northern boundary of import area Min X = Western boundary of import area.
    2. Max X = Eastern boundary of import area Min Y = Southern boundary of import area.
  8. Click on the Reader Options tab and make sure Invert is unchecked.
  9. Click Execute.
  10. Geocap will report if the grid has been imported correctly; click OK and close the import dialog by clicking Cancel.
  11. Observe that the new data set has appeared in the Grids folder.
Exercise

Convert the grid to the right projection and display

  1. Click the seabed grid and go to the Shared commands section in the Toolbox.
  2. Double click the Convert to... command you want to use, in the Operations folder.
  3. Define the appropriate settings.
  4. Change the result combo box to Replace input.
  5. Click Execute.
  6. Agree to replace the existing dataset by clicking Yes.
  7. Geocap will report if the grid has been converted correctly, click OK and close the conversion dialog by clicking Cancel.
  8. Right click the dataset, choose Set Schema and choose Sediment Thickness.
  9. Display the dataset together with the coastline.

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Generate or import a Baseline

The baseline is needed in order to generate distance lines. The coast may also be used as a baseline (by changing the schema accordingly), but then the computing time may be very long. If you do not have a baseline for your area, you may generate a dummy to use as an approximation based on the coast line you imported in a previous exercise.  If you already have imported an official baseline you may jump to the import baseline exercise.

Exercise

Generate dummy baseline

  1. Display the coast line called GSHHS, which should have been imported in 1. Maritime Lines / Coast lines.
  2. Open the Digitizer by selecting Tools > Quick digitizing from the main menu.
  3. Check the option Save also in folder, and click the Browse button.
  4. Select the Base lines folder under 1. Maritime Lines, and click OK.
  5. Click Start digitizing.
  6. Digitize the points on the coast line by pressing j on the keyboard. The picks will automatically snap to the nearest point on the coast line data set. Digitize a rough version of the coast line by picking the outermost points on the coast line.
  7. When you are finished digitizing click the Stop digitizing button. The digitized line should appear in the Base lines folder.
  8. Click the X to close the digitizing menu.
  9. Locate the digitized baseline in 1. Maritime lines / Base lines.
  10. Right click the baseline dataset and select Rename.  Rename the data set to your country name and _baseline. Click OK.
  11. Right click the baseline dataset, and select Set Schema > Base line.
  12. Right click the baseline dataset, and select Properties > Geodetics.
  13. Click Set geodetic meta data and specify your settings.


Digitizing a baseline


If you already have a baseline you want to import you can import it using the ASCII import menu, or Generic import if you have a Shapefile. The exercise below is for a baseline in ASCII format. If you created a dummy baseline in the previous exercise you can skip this exercise.

Exercise

Import baseline

  1. Right click the Base lines folder under 1. Maritime Lines and select Import > ASCII Column
  2. Click the browse button and browse for your baseline file.
  3. Make sure the Coordinate format, File column, Cell type and Schema is set correctly.
  4. You may add a column for point name if the file contains point names.
  5. Click Execute to import the file.
  6. If the coordinates in your file was in Latitude and Longitude you need to convert it to the right projection.


Generate Distance Lines

We can now proceed to generate the distance lines we need for our project. The 200M line and the 350M line.

Exercise

Generate the 200M and 350M lines

  1. In the folder 1. Maritime Lines / Base lines right click your baseline and click Generate 200M line.
  2. Use the settings you want and click Execute.
  3. Generate the 350M line also.


Depending on your project area parts of your 200M and 350M lines might be on land or in none relevant areas. We can clean this up and remove this part of the line using the Edit points and lines command.

Exercise

Clean up the 200M and 350M lines

  1. Select the 200M line in your project.

  2. Find the Edit points and lines command in the Toolbox. You might have to add it by right clicking a folder in the Toolbox and selecting New command.
  3. Use the command to delete the part of the line you don`t need.
  4. Do the same with the 350M line if needed.

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Distance Constraint

We are now going to create the last distance constraint, the 2500m isobath + 100M.

Exercise

Generate the 2500m isobath

  1. Right click the seabed grid in the 2. Seabed / Grids folder and click Generate 2500m Isobath. 
  2. The command will generate a new dataset. Click OK.
Exercise

Edit the generated 2500m isobath

  1. Clear the display window by clicking the X button in the main toolbar.
  2. In the folder 2. Seabed / 2500 meter Isobath right click the 2500m isobath and select Zoom to Data and then display by selecting Light Blue (2500m Isobath).
  3. In the folder 2. Seabed / 2500 meter Isobath right click the 2500m isobath and select Edit points and lines...
  4. Use the command do delete the parts of the line that we are not going to use as input to generate the 100M line.
  5. Click Execute when you are finished.
Exercise

Generate the 2500m isobath + 100M distance constraint

  1. In the folder 2. Seabed / 2500 meter Isobath right click the 2500m isobath and select Generate 100M Line.
  2. Keep the default settings and click Execute.
  3. The command will generate a new dataset. Click OK.

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Generate or Import Bathymetric Profiles

Before we start analyzing the foot of slope we need bathymetric profiles. Initially you might want to create bathymetric profiles from the seabed grid, but you also need real bathymetric profiles. In the next two exercises we are going to create a few bathymetric profiles from the seabed grid and then import real bathymetric profiles from GEODAS.

Exercise

Generate Bathymetric Profiles

  1. Display your seabed grid in the folder 2. Seabed / Grids.

  2. In the folder 2. Seabed / Grids right click your seabed grid and click Generate Bathymetric Profile.

  3. Find and area where you want a bathymetric profile and digitize it.

  4. Continue to generate profiles until you think you have enough.

  5. Rename your profiles so they have a useful name.


In the next exercise we will download a "Corrected Depth Bathymetry" from the U.S. National Oceanic and Atmospheric Administration's (NOAA) Geophysical Data System (GEODAS) and then import this profile using the ASCII Column importer in Geocap.

Exercise

Download Bathymetric Profiles from GEODAS

  1. Go to this link: http://www.ngdc.noaa.gov/mgg/geodas/geodas.html
  2. Click Trackline Geophysical Data Viewer.
  3. Zoom in to the area you are working in.
  4. Click on a line which you thing would be useful to analyze.
  5. Click on Get Marine Data for these Surveys in the popup.
  6. On the site that comes up, change the format to XYZ with Z value as Bathymetric corrected depth.
  7. Follow the instructions on the site to download the data.
Exercise

Import Bathymetric Profiles from GEODAS

  1. Right click the Bathymetric Profiles folder under 2. Seabed and select Import > ASCII Column

  2. Click the browse button and browse for your bathymetric profile.

  3. Make sure the Coordinate format, File column, Z, Cell type and Schema is set correctly.

  4. Click Execute to import the profile.

  5. If the coordinates in the profile was in Latitude and Longitude you need to convert it to the right projection.

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Foot of Slope Analysis and Hedberg points

You should now have several bathymetric profiles in your project, and we can proceede to analyze these to find FOS points.

Exercise

Analyze your profiles

  1. Right click on of the bathymetric profiles under 2. Seabed / Bathymetric Profiles and click Analyze.
  2. Try out different settings in the analysis window in order to find a FOS point you think the Commission would accept.
  3. Save the analysis and type in a useful name for your FOS point.
  4. Analyze FOS points for the rest of your bathymetric profiles.


After you have analyzed all your profiles and created FOS points we will merge the FOS points in order to create one set of Hedberg points. 

Exercise

Group FOS points

  1. Create a new folder under 2. Seabed, called FOS points.
  2. Right click one of the FOS points you have created and click Merge Foot of Slope points.
  3. Add the rest of your FOS points to the list and set the FOS points folder as result location.
  4. Click Execute.
  5. Type in a useful name for your FOS point group.


We are now going to generate the 60M line from the merged FOS points.

Exercise

Generate 60M Hedberg points

  1. In the folder 2. Seabed / FOS points right click your group of FOS points and click Generate 60M line.
  2. Use the settings you want and click Execute.

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Generate Gardiner points

We will now investigate the sediment data in the area and try to generate Gardiner points using the global sediment thickness grid and the FOS points we just created. Note that there might not be enough sediments to produce Gardiner points in the area you are working in.

Exercise

Calculate 1% of the distance to the closest FOS point

  1. In the folder 3. Sediment Data / Grids right click Sediment Thickness and click Generate >1% dist to fos Area
  2. In the menu that pops up, click the browse icon and browse for the group of FOS points.
  3. Make sure that Store in project is checked.
  4. Click Execute.
  5. Investigate the Gardiner points.


Create Outer Limit

Now that we have all the relevant data in our project we can proceed to copy all our formula lines and constraint lines into the Outer Limit folder and generate the outer limit.

Exercise

Copy your data to the Outer limit folder

  1. Copy the 200M line, 350M line, Hedberg points, Gardiner points.
  2. Paste them into the appropriate folder in the 4. Outer limit folder.
Exercise

Generate the outer limit

  1. Right click the folder 4. Outer limit and click Generate Outer Limit.
  2. Use the tool to generate your outer limit.