In "search by map" you can combine an alpha/numerical query with a geographical query. The alpha/numerical query can be selected on the left side of the screen and the geographical query on right side (figure 1). In this text numbers between brackets refer to the numbers on figure 1.
Defining an alpha/numerical query
Define a query using the text en pulldown boxes.
- Free Search:
Type in any character string you wish to search in the database. You do not have to use wildcards etc.
- Available format:
select a format. The database will only select datasets that are available in that format.
- Keywords:
This is a list of all usefull words occurring in the descriptions of the datasets. Select a word and only those datasets will be selected containing that word in the field description.
- Compilation year:
This is an indication of how recent a dataset is. If you want very recent data type in a recent year and check the > for all years more recent than the year you entered. If you check < all data from that year and older will be selected.
- Sort result by:
The result of the query will be displayed in a table. By selecting a field here you are able to determine the order of the result table
- Inside/outside
This indicates if a selected dataset falls completely within the rectangle drawn on the map (inside) or only partly within that rectangle (outside).
Click on the Search(12) button to send your query to the database
Click on the Clear(12) button to delete your query definition
After clicking on search, all relevant records will be collected from the database into a results table.
Defining a geographical query
There are two ways of defining a geographical query on the map.
- drawing a rectangle on the map
- Draw a rectangle on the map by clicking the left mouse button on the map and dragging the mouse until the rectangle covers the area for which you wish to select data (upper-left en lower-right corners of the rectangle will be shown on (11)
- Then click on search (12)
- Defining a rectangle by entering an upper-left and lower right corner(11)
- First enter a an upper-left and lower-right co-ordinate. Enter a latitude in the first and a longitude in the second text box (use a "-" for South and West co-ordinates)
- Then click on search (12)
After clicking on search, all relevant records will be collected from the database into a results table. all selected data points are then displayed on the map. The map will be automatically zoomed in/out to show the selected samples.
Combining both query forms
You can combine both query forms if you wish. For instance first define a rectangle, then select an instrument and/or country from the pulldown list and subsequently click on search.
Functionalities of the map
The map area will be automatically zoomed in on the selected records after you do a query on the database. Apart from this automatic zoom you can use the options listed left of the map area. Click on one of the options to select it. Click on the map to activate the option.
- Zoom in one step (full map area)(6)
- Zoom out one step (full map area)(7)
- Pan(8)
The map will be panned using the location of your mouse click as the new centre of the map
- Identify(9)
Click on the location of a sample point/area to select the metadata for that sample.The sample will change colour and the relevant metadata will be shown in the lower half of the screen.
- Zoom in on a defined rectangle(10)
First draw a rectangle as described above, then click on (10)
NOTE: Do not draw a rectangle when using options (6), (7) and (8). Be aware that by slightly shifting your mouse on the map area you might draw a rectangle un-intenionally. The result will be that these functions do not seem to work.
Changing layers in the map
There are several additional layers in the map that you can switch on and off (1).
- Grid- and contour (bathymetry) lines (1)
click the check box(es) of the layers you wish to be displayed on the map and click on redraw(3). The map will be re-drawn to include the selected layers.
- labels (2)
Click on the check box of the label you want to be shown with each selected sample, then click on redraw.
NOTE: Use this option with care, labels may completely cover your map with text.
Miscellaneous options
- Reset(4)
Click on reset to re-draw the default world map. All additional layers will be switched off automatically.
- Fullsize (5)
Click on Fullsize to draw an enlarged version of the map in a separate window. You can save this enlarged window as a GIF picture on your local PC.