Search Criteria: Search Area(s)

About Search Areas:

You can choose polygons and rectangular Search areas. GEODAS will Search for any surveys that are at least partially contained within the Search area(s). GEODAS uses negative numbers for South latitudes and West longitudes.

Area Searches are performed by matching user criteria against representative points which are stored in the GEODAS Inventory files. These inventory points describe the location of the actual data. Marine Trackline database and Aeromagnetic Survey database inventory points may be as much as 90 nautical miles apart, therefore, Search area limits for these databases should generally be no smaller than 90 nautical miles across, i.e. 1.5 degrees latitude at the equator.

How to change your Map View:

View... Zoom In: zoom in with either mouse or dialog:
(a) choose Drag Box w/Mouse. Place the cursor on the map. Hold down the mouse button and drag mouse to define zoom area.
(b) choose Dialog Lat/Lon Entry to use keyboard to define top-bottom-left-right limits of zoom area. Enter latitudes and longitudes in decimal degrees, with up to 3 decimal places. Longitude values must be between -180 and 180.

View... Zoom Out: changes to larger map view
View... World (180-180) (world map centered on 0 degrees longitude)
View... World (0-360)B (world map centered on 180 degrees longitude)

Selecting Search Areas:

Select-Area(s)... Undo to remove the most recently defined area. Undo may be repeated to remove multiple areas.

Select-Area(s)... Lat/Lon Box... to define a rectangular area
(a) choose Drag Box w/Mouse. Place the cursor on the map. Press the Mouse Button, hold it down, drag mouse to define search area.
(b) choose Dialog Lat/Lon Entry to use keyboard to define top-bottom-left-right limits of Search area. Enter latitudes and longitudes in decimal degrees, with up to 3 decimal places. Longitude values must be between -180 and 180.

Select-Area(s)... Polygon(s)... to define polygon area(s)
(a) choose Define Using Mouse, click the mouse at each point of the polygon, double clicking the last point to close polygon, or
(b) choose Dialog Lat/Lon Entry, to enter a series of latitude/longitude points which define your polygon. You do not need to repeat the first point of the polygon as your last point.Enter values in decimal degrees, with up to 3 decimal places. Longitude values must be between -180 and 180. The orientation of your polygon points is determined by the current map bounds. e.g. if you wish your polygon to cross 180 and not go the long way around the globe, first change your Map View (see above) to View... World (0-360).

Retaining the Results:

File... Accept will retain your area choices as Search Criteria.
File... Clear All will remove the areas you have defined for this Search. If areas were previously defined for this Search and entered into Search Criteria, those areas can be removed with File... Clear All, then File... Accept.
File... Cancel will return you to the Select Search Criteria menu without retaining any area selections made here.