Marine Geoscience Data Management System

GeoMapApp Help


Layers Interface

The Layers Interface is under development, and will change significantly, and sometimes rapidly, as new features are added and widgets are modified.  At present (9/21/05), you can import some shapefiles (ESRI format, file suffix - .shp), GMT grid files (file suffix - .grd), and two databases - Alvin Photos and a set of NGDC grids for U.S. coastal areas - from a list.  The list will grow, and new categories will be added.






The button on the main tool bar toggles a Layers dialog:

When layers are imported, the dialog looks like this:

The table on the left is a list of the shapefiles that have been imported.  The table on the right is the attributes table for each shape in the selected shape file.

Layers Tool Bar:

  • Clicking the button opens this help page in a web browser.
  • Click the button to add layers.  Another dialog pops up:

- Importing shapefiles
- Importing grids
- From list
    - Photos
    - Grids



  • closes the selected shapefile.
  • If is enabled, clicking it will open a browser page with additional information on the data.
  • Clicking will zoom to the bounding box of the selected shape (right table), or, if no shape is selected, of the selected shapefile.  If the selected shape is a dimensionless point (type = 1, 11, or 21), the zoom will not do anything.  Control+click on the selected shape to de-select it.
  • Clicking opens the selected shape. One of two things will happen:
    1. A new shapefile will be added to the left-hand table, or
    2. A dialog will open for viewing/interacting with the data associated with the shape



In the step-by-step example below, we will load and view Alvin photographs from the East Pacific Rise at 9N. These photographs are on a server hosted at WHOI and are accessed by GeoMapApp remotely.

To begin, select Alvin Photos in Ridge2000 ISS folder and press OK to load. The shapefile DiveNav is now listed in the Layers window. Select this shapefile and the list of Alvin dives within this shape file will appear in the attributes table (right hand of window). Now press to zoom to the bounding box of this shapefile.


                                                                 last modified 9/21/05

Now if you select any dive within the attribute table, the navigation track for this dive will be highlighted in map view. Or you can select a track in map view and the corresponding dive will highlight in the attribute table.  Once you select a dive, the open shape tool is activitated and turns yellow. Clicking on the open shape tool opens the shape file for that dive so it now appears in the shape file table and a list of all Alvin photos for that dive appears in the attributes window. The location of each photo is now plotted in map view. Click on the open shape tool again to open the Photo window.  Use the toggle menu in the Photo window to choose between both of Alvin's cameras. Use the arrows to advance forward and backward through the dive.



You can now navigate through the dive by clicking on photo locations shown in your map view or using the arrows in the Photo window.



You can open and view multiple shapefiles. For example, go back to the Import Layers menu, select Alvin Imagenex grid. Click Ok, Select the EPR_composite in the shapefile table, click on open shape tool and Load Grid to display a 1-m resolution bathymetry grid which was created using the Imagenex sonar on Alvin.


Use the to close any shape files you are finished with.




To import a GMT grid file (in GMT’s netCDF .grd format) click the Layers button to open the Layers dialogue box.

Click the Folders button to bring up the Import Layers dialogue box.

Select Import Grid and hit OK. The ImportGrid window appears.

Click the Import Grid button. An Open window appears and allows you to browse for your GMT .grd grid file.

Select the grid that you wish to import.

Click Open. A new window, called define projection, pops up.

In the Projection drop-down menu, select between Geographic and UTM grid projections. For a UTM grid, select the UTM zone. Hit OK. The grid is now being read in to GeoMapApp and is being indexed in each of the levels of nested resolution. The progress of this indexing is displayed in the Import Grid window.

When the grid has been indexed, an entry for it appears in the Layers window. Note that due an error the name of the folder containing the grid is listed, not the grid name itself.

Use the mouse to select the grid by clicking once on its (folder’s) name

To make the grid visible in GeoMapApp, click the yellow light bulb symbol to bring up the Load Grid window

And click the Load Grid button. This loads the grid into the GeoMapApp interface window where it is visible as a geo-referenced overlay, and the Palette Tool window appears.

Use the zoom buttons to zoom in to the area of your grid.

The imported grid can be manipulated (coloured, illuminated, contoured, profiled, saved, overlain with imported data points, etc) in just the same way as the native GeoMapApp DEM tiles. Note that the imported grid is not merged with the GeoMapApp global DEM tiles – it is a geo-referenced overlay grid.