You may use Hydro-Plot to edit, delete and add data points to the data file you have downloaded from GEODAS CD/DVD sets, data files on the CD/DVD itself, or custom grids you have created with GEODAS Grid Translator. (You may also edit most ASCII XYZ Formatted data, regardless of the source. If you are able to display a XYZ file in Hydro-Plot, you can likely edit it successfully.)
A log file will be automatically be created for you summarizing the edits you have made to the file(s).
You edit data by selecting individual points on the Hydro-Plot map. (Note that to select points you must zoom the map in to the point where 10,000 or fewer points are visible.) Once the point is selected you simply click the right (secondary) mouse button on the map. Or, with no points selected you can create new data records. Right Clicking will bring up a popup menu with these menu items:
Edit Record - When you click on this option an editing box will appear with the current values for latitude, longitude, value, and (for some formats) type and carto code. See GEODAS Data Files for descriptions of these record fields. You may edit these field values, but be careful to put your entries within the bars ( | ) between the fields.
Save Record Changes - Use this option to save changes you made to the record. Note that these changes are queued but not actually made to the file until you choose Save Changes As File.
Delete Record (or Set to NaN or Land). Click on this option to delete the currently selected record, or for gridded data, to set the grid cell to the "Empty Grid Cell Value" NaN. For data grids and grid-radius grids the NaN represents a cell with no value. For NGDC supplied density grids NaN represents Land values. Note that you are deleting the Current Selected Record, not the record closest to your right mouse click. (For MGD77 formatted data, you can delete the complete record, or you can delete the specific MGD77 field of bathymetry, magnetics or gravity being displayed. If you choose to delete just the field, the current field value will be replaced by a 9s filled field.) Deletion will take effect when you choose Save Changes As File.
Undo Edit/Delete Use this option to undo edits or deletions on the selected record. Note the asterisks in the label of the selected record, indicating that this is an edited or deleted record.
Create Record Use this option to add new records to the file. Select this option, then click on the map at the position of your new record. You may then edit the latitude, longitude, depth, cartographic code, etc. in the editing box for your new record. Note that for grids, you would not use this option for creating new grid values. Instead, use the Plot Parameters… option, selecting Show NaN Cells, and then change the NaN (empty grid cell) value to a depth.
Add This Record Once you have created a record and are satisfied with the values, use this option to make the addition. Note that the addition is queued, but not actually made to the file until you choose Save Changes As File.
Save Changes To File Use this option to save all your changes (including deletions and additions) to file. Where the input file is not Read-Only, the saved (edited) file will have the same name as the input file, and you will have the option to save the original file data, which will be renamed with "_1" added to the end of the file name prefix. (e.g. for input file mykey.a93, the edited file will be named mykey.a93; the unedited data will be saved as file mykey_1.a93.) (For these files, should you open and edit your data more than once, the original file name will always contain the latest version.) If you opened a Read-Only file, for example from the CD, you will instead be presented with a Save As Dialog for saving the edited version of the file.
Cancel / Remove Labels You can use this option to cancel editing actions before they are completed, or to simply remove the lablel(s) for points which you have selected.