GPIPS

About the Data Products

GPIPS data products currently available include access to the developing point source catalog, which includes polarimetric and photometric data, as well as image files of fields as they are processed. This website provides two approaches to querying the database for both types of products. The Short Form is short and uncomplicated to fill out. The query is made strictly by some type of location, and will contain set attributes about either the fields or point sources found, depending on which is searched for. The Long Form allows a greater amount of user-control in structuring the query by specifying more detailed search parameters as well as allowing the user to specify which attributes, along with a few fixed attributes always provided, are returned. More detailed information about the data query forms is available in the About the Forms page of this website.

Initially Displayed Search Results

In all cases of the website succeeding in its tasks, the search results will either be displayed in an html table or the website will indicate that no results were found given the search parameters entered. Only up to the first 200 results will be displayed in this html table, which, depending on how many types of information were requested to be included in the results, may be wider than the normal page width. In many cases, a column of the results may consist of links to image files, depending on the data parameters returned in the results. These images are in the .fits format of files, and can be downloaded by saving the target of the link to disk. While the html table is a reasonably aetstetically pleasing method of returning results, it is not very useful to someone who would like to use the data. Additionally, it only contains the first 200 results. If you find that you would like all the data found by the database query in a more useable form, we have provided the option to obtain an ASCII (plain text) listing of results either by email or by downloading it from the website. The search results, if you choose to ask for a link to be displayed, will only be available for approximately three days. The method of acquiring the ASCII file is by filling out the short form at the bottom of the page with the html table on it. A link to the bottom of the page is provided at the top of the page.

There are two sets of options options presented concerning obtaining an ASCII (plain text) version of the search results are about the search results themselves and about the method of delivery of the results. The ASCII file is actually generated after performing another query of the database, so the user can either choose to receive the same results as received from the initial query, or to get every piece of information stored in the database that relates to the search results. (An example would be if the inital results only displayed a listing of field numbers, then selecting "all information available" would give an ASCII file that included the coordinates, availability, dates, and processing information about those same fields. This will not change the search results, except to give more details about each point source or field in those results.) The second set of options is whether the user would prefer to have the results emailed to them, to just download them from the page, or both. If the email address provided does not match the software's email address checking routine, then the information will only be available by download.

ASCII Files of Search Results

The ASCII file is initially created with a filename that uses the microtime of the request and the IP address of the user requesting the ASCII file. If the user chooses to only receive the file by email, the original file is deleted after being mailed. If, on the other hand, the user chooses to download the file from the website in any manner, it will be retained on the website for approximately three days with the same file name it had at creation. The directory that the files are kept in will not allow a directory listing.

The following image is a screen shot of an ASCII file of search results for point sources. The .dat file can be opened with any text editor, or can be imported to a spreadsheet program, noting that the fields are fixed widths, not delimited by tabs, spaces, or commas.


Screen shot of an ASCII file containing search results for point sources. The IP address portion of the temporary filename has been blacked out.

The sections of the file are the header, the table column headers, and the tabulation of the data. The header indicates that the fields are fixed length, the number of search results, and the computer from which the information was retrieved. The next lines are the UT date and time of the retrieval in RFC 2822 format, the name of the file at its creation, and the name of the file that it was sent as if the file was emailed. (In the example, the file was not emailed, and so that line does not exist.) The name of the database is included on the next line, followed by part of the query that the database management program used in order to perform the search. A brief note is included about 2MASS and GLIMPSE data, as well as information about attributing GPIPS-created data. The final parts of the header are the information about retrieving image files, and that the tabulated information follows. An example image file, if the filename column displayed 9999.fits, would be located at http://gpips0.bu.edu/temp/9999.fits.

The table column headers consist of four lines. The top line indicates the name of the column, the second line desingates the type of variable that the information is stored as in the database, the third line indicates the units of that information, and the fourth line indicates the default value for that information. The possible column names and the information they describe are: