Frequently Asked Questions
What do I do if the program hangs, or appears to hang?
The first solution to this problem is try to be patient. The converter can take a long time with some of the larger files, and will often times appear to hang when really it’s doing it’s job just fine,. Unfortunately, often times it will simply stop working without giving an error message or changing it’s appearance. If you’ve feel this has happened try clicking the “Exit” button on the original screen, if the program has hung this will almost certainly stop it.
If it does hang the overwhelmingly most likely possibility is that it ran out of memory, the program is very memory intensive, and even moderately sized files can cause high memory usage. Java programs default to being able to use only a small amount of memory. If you're file is around 100MB or larger, this could be an issue, or if you have less than 512MB of RAM on your computer.
What if there is no time or depth?
Latitude and longitude are both required for the program to run, but time depth are always optional. When creating a configuration file the defaults for time and depth will be zero, if you leave the fields that are filled in as they are then it will assume no time or depth. For specifics on how to define no time or depth see the different file types.
What if I have other variables?
The only variables allowed are latitude, longitude, depth and time. It also only allows one data type (for instance, if a file had both temperature and density on a grid, only one of those data types could be saved). If the file is in column form then the program will ignore them, if they make up a dimensions (if the data changes along latitude, longitude, and this other dimensions that is neither depth nor time) then the conversion will create faulty data.
What if my file isn’t in any of these formats?
The most generic, basic file formats were picked for this program, ones that were found commonly among various data that were converted. However, it is quite likely that your data format will differ, perhaps slightly, from all of these different types. If this is the case you can do one of three things:
1) Write a add on to this program that will convert your file type (see creating a file type). This is time-consuming and complicated, and unless you anticipate widespread use of your file format, probably not worth it.
2) Not use this program and convert the file to NetCDF, or to CDL and then NetCDF yourself. This is certainly possible, but the reason this program was created was because of the difficulty of mastering the NetCDF format (or CDL format). If you do choose this path, you may wish to go to Unidata’s NetCDF site.
3) The preferred approach would be to convert your data into a format that this program does understand. Most likely this will be by far the simplest and fastest route to converting your data to NetCDF. The formats that can be handled are quite basic and straight forward, converting to them should be a quick process.
What if I have more than one file?
Unfortunately the file converter can only take one input file. If you have multiple files that you want to append, or one for each depth sample or something similar you will have to turn them into one file yourself.
What does the error: “Can not open file of type __” mean?
This is an error from the configuration file you selected. It means that the file type listed in the configuration file is not a type the converter recognizes (it’s a number between 1 and however many different file types can be converted). Check the configuration file to make sure that the very first line ends in a colon followed by a space and the appropriate number.
What is an error occurring from “____.BuildClass()” or from"CConfigFile.CreateClass()" mean?
Most likely an error of “null” was returned for this error. It means that there was some error reading the configuration file, most likely that a line is either missing or is in not in proper format. To avoid this error, try re-creating the configuration file using the program’s interface. If you want to try and fix this manually, remember that the configuration file’s data is either attributes, or ends in a colon, a space, and whatever data is on the line.
What if I have multiple data variables?
Sorry, only one variable at a time with the file converter. If your data is in column form, it is very easy to create a different file for each variable (simply change the column number for the data variable), but you can not create one file with all the variables in it. This is allowed by both NetCDF and the IDV, so if you wish to create such a file it is practical, but you’ll have to use tools besides this program.
What effect does the “Positive is Below” setting have on the modification limits?
The file converter makes the change of depths (if “Positive is Below” is set) after modifying the data. That means that if your file has depths from 20 to 30, labeled as positive in your file and you want to only have 22-28, you should use positive 22 and positive 28 as your limits, even though they will eventually be changed to negatives.
If I don’t have depth or time in my file, how does the Modify File Window work?
The Modify File window will always allow you to change both the limits and resolutions, even if the data that they’re supposed to be affecting isn’t there. So you can change the range of time allowed even in a file that has no time (though this would be a waste of your time). The resolution field in the depth/time window will have an effect on whichever one exists. For instance, if you have depth in your file, but no time variable, setting the resolution to ‘2’ in the depth/time pane will still filter out every other depth, and same would go for only time and no depth.
To what extent can I modify a point file?
A point file can be partially modified through the “Modify File” window, the limits on latitude, longitude, depth and time can be set and will filter out any data not within those limits. However, though the resolution field can still be changed, it will have no effect on the data.
My point file is not recognized in the IDV
The IDV recognizes point files by the file name. They must end in _eq.nc, if your file name does not, the IDV will not know that it is point data. Also, point data currently only works in GEON’s version of the IDV, if you’re using the version downloaded from Unidata it will not recognize point data no matter what.
The data from my binary file looks wrong, what happened?
When converting a binary file, you must make sure that the data types you specified are exactly right, or you can get a bad file output without any run-time errors. Some common pit-falls to watch for are the “endian-ness” of the file, the data type and size used, and making sure that the data is signed (unless it’s unsigned bytes). For more information and a more detailed explanation, see the binary file description.
What if the units in my file aren’t the standard ones?
Both NetCDF and the IDV allow for various units (NetCDF allows for any units, and the IDV has a specific set that it will recognize). The file converter defaults to standard units, depth in kilometers, latitude in degrees north (“degrees_north”), longitude in degrees east (“degrees_east”), and time in “seconds since 1970-01-01 00 UTC”. Any of these may be changed by the user, though you should take care to use units that the IDV recognizes or it will not properly display your file, should it display it at all.
You can change the units by opening the attribute window in the file creator pane, then click on “remove attribute” by the unit you will be changing. Then click on “add attribute”, and select the appropriate variable whose unit you’re setting, then set the title to “units” and the text to the unit itself. For example, to change longitude to degrees west, remove the “lon”, “units”, “degrees_east” attribute from the attribute pane, then add an attribute to the variable “lon”, titled “units”, and with a value of “degrees_west”, and click on add attribute. The file will now store longitude as being in degrees west.
You may set the data variable units (the “var” in the attribute pane) to any that you wish. The IDV will recognize certain units and not others, but will display even those units that it doesn’t recognize, or one with no units at all, which is the default for the file converter.
Why is the number “1.7976931348623157E308” in the modify file pane?
The file converter defaults to having this number as it’s maximum, and it’s negative as it’s minimum for all of the different variable (lat, lon, depth and time). This number is the maximum value that the variables can be, and thus, by definition, includes every possible variable. This is designed to make sure that the default values do not exclude any of the data you put in. These values can be changed if you do wish to limit the area converted in your file.
Why did the “Exit File Creator” button disappear and how can I exit now?”
When the width of the window becomes too small, the exit button can disappear, all that you need to do is make the window larger and it will come back. Or, if you want to keep the window that size, clicking the ‘x’ in the upper right of the window serves exactly the same function as the exit button (it doesn’t do any harm to use that button to exit).
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