This exercise will briefly introduce ODV to create an ODV collection from the World Ocean Database

Transcription

1 Topic 6b : Creating ODV Collections from WOD Data. Ocean Data View (ODV) is a software package for the interactive exploration, analysis and visualization of oceanographic and other geo-referenced profile or sequence data. ODV can display original data points or gridded fields based on the original data. ODV can be downloaded here. You will need to register as a member of the ODV users group first. This exercise will briefly introduce ODV to create an ODV collection from the World Ocean Database Exercise Title: Creating Ocean Data View (ODV) Collections from World Ocean Database (WOD) Data Abstract: Straightforward methods to create ODV collections from the four Liberia ocean datasets downloaded from ODV are shown. The World Ocean Database native parameters, structure and quality flags will be used. Preliminary Reading (in OceanTeacher, unless otherwise indicated): Bathymetry and Topography Physical Oceanographic Measurements (for salinity and temperature) Chemical Oceanographic Measurements (for other chemical species) History of Chemical Measurement Units Marine Data Quality Flags Required Resources: Ocean Data View (ODV) osd_ _terengganu_wod - Data collection made in the previous exercise Obtaining Area- Specific Marine Data from the World Ocean Database

2 1. Install and run the latest version of ODV. 2. Select VIEW > SETTINGS to open this set of general program controls. The settings in VIEW are probably already OK. 3. Select MAP > RESOURCES to see the various bathymetry (and coastline) datasets available in ODV's map mode only (i.e. when you're viewing station locations on a horizontal map or in section mode). You can make experiments on your own to see what's best for you.

3 NOTE: For actual research projects, which sometimes can occupy small regions, you should select the highestresolution coastline and bathymetry data available. These are choices you must work out on your own. 4. Select IMPORT > WOD IMPORT and uncheck the box for SHORT LABELS. We want long cruise labels in order to see more information. 5. Select SYSTEM > PROGRAM LOCATIONS and browse to your favorite browser on the top row, and to your favorite ASCII editor on the bottom row. NOTE: Firefox and ConTEXT are highly recommended.

4 6. Select SYSTEM > SIDEBAR folders. These will give you easier navigation to your data folder to supply ODV and your products folders to receive from ODV. For the first one, select the folder PROJECTS > LIBERIA > DATA > OCEAN For the second one, select PROJECTS > LIBERIA > PRODUCTS > ODV Then click OK to save all the above settings. 7. Select FILE- NEW to begin the collection creation process.

5 8. Navigate to the folder PRODUCTS > ODV > COLLECTIONS and enter the name osd_terengganu_ wod. Then hit SAVE. 9. This window open, asking you to select the structure of your new collection. Many existing structures, defined by the variables they contain, are offered. Also you can use some standard templates, or even specify the variables individually. Select World Ocean Database Then click OK.

6 10. This global map opens, indicating the new collection has been created. But the collection is still empty, and it has no station dots. NOTE: The gridded bathymetry you see here is the GEBCO01 default (the one you selected in Panel 3, above). 11. Select IMPORT > NODC FORMATS > WOD 12. Navigate to the DATA > OCEAN > WOD folder, and select the ocean station data (osd) you downloaded. Then click OPEN. NOTE: The author has some extra folders here, an option you can follow later on your own time.

7 13. This IMPORT OPTIONS window appears. You can see that all the SOURCE FILE VARIABLES have an asterisk beside them, just as the TARGET COLLECTION VARIABLES do. This indicates they are "matched up" and ready to import. This is no surprise, because the structure template you used is an exact mirror of the WOD structure. There are these possibilities: ASSOCIATE - the source and target match up CONVERT - the source can be converted to match up with the target USE DEFAULT UNDO - an existing match-up is not yet correct; it needs work UNDO ALL - remove all existing matchups and start over Click OK to continue.

8 14. After a short time, many red dots appear in the area of interest, and finally this message appears. Click OK. 15. Now you have an ODV collection of bottle data.

9 16. Right-click on the map, and select ZOOM. Then drag the corners of the red frame inward toward the data area. You can doubleclick inside the red frame when you have the area you want. 18. After perhaps more than one try, you will have a map something like this. NOTE: An alternative to physical zooming is to right-click on the map and select STATION SELECTION CRITERIA > DOMAIN. Here you can enter coordinates that are exactly along the edge of your area or slightly larger. Then click OK.

10 19. To save this map view, select VIEW > SAVE VIEW AS 20. In the VIEWS folder of ODV, enter the name station_map_all and click SAVE. (The location and extension will be automatically set by ODV). That's all you have to do to make the collection; there is no need to SAVE it, as you would do for other software programs. And whenever you open this collection again, by selecting and opening the file osd_terengganu_wod.odv, you can return to this same view with VIEW > LOAD VIEW. 21. Use the same steps as above (beginning in panel 2) to make new collections with the other 3 datasets you downloaded from the WOD. 22. You will have these collections when finished: PRODUCTS > ODV > ctd_terengganu_wod.odv PRODUCTS > ODV > xbt_ Terengganu_wod.odv Might also be xbt_mbt_ Terengganu_ wod.odv - If your WOD download included mechanical bathythermograph data PRODUCTS > ODV > pfl_ Terengganu_wod.odv

11 23. Also make and save good maps of these collections. Here is the CTD data map. Remember, to save a graphic, use VIEW > SAVE VIEW AS, as you did above. 24. Here is the XBT data map. The long straight lines of data stations are a sure sign of shipof-opportunity data.

12 25. And here is the profiler data map. 26. Now you're ready to move on and make some standard data analysis products with ODV.