Help on Interface Screens : 3.45. Primary Data Search Form

The Primary Data Search Form allows you to specify data set names, geophysical parameters, instrument sensor names, geographic region, time range, and other attributes to find data sets and their associated data granules.

Three methods are available to choose data sets or other keywords:

1. Choose Data Sets (By Discipline/Mission)

   This method allows you to view a list of available data sets filtered according to scientific discipline and instrument or science mission. After you have selected a data set or data sets, you can also further specify your search by adding additional keyword. Clicking on the "Choose Keywords for Selected Data Sets" will take you to separate pages where you can choose more keywords specific to the data sets you have chosen. For example, after choosing a Landsat 7 data set, you can also add "cloud cover" as an additional search criteria.

   This method focuses primarily on data sets that are more "in demand". For example, the instruments and missions listed for use by this method will show any Earth Observing System and Landsat data sets that are available through the EOS Data Gateway. If, however, your data set of interest is not shown by this method, clicking on the "Show List of All Data Sets Available" will give you a comprehensive list of all available data sets, and you can use that list to find and choose what you are looking for.

2. Choose Data Sets (Text Search)

   Type in earth, atmosphere, ocean, or land science terms into the text entry box, then hit the Text Search button. The system will return a list of relevant data sets from which you can choose for your search.

3. Choose Keywords for One or More Categories (By Categories)

   From the menu, choose a keyword category, then click the "Choose keywords for >>" button. You will then be taken to a page listing all keywords in that category. You must choose one category at a time, but you can use this method multiple times to add additional keywords to your search.

Choose Search Area

You can use the Find location using Gazetteer link to lookup by name a features coordinates. The coordinates can then be entered on the search page using one of the ways listed below.

The system defaults to a global search (all latitudes and longitudes), but it is recommended that you define as small a geographic search region as possible so the system can return data that best meets your needs. There are a number of options to choose from to define your search region of interest:

• Orthographic Map (Java): This map provides an orthographic projection of the Earth. The map is written as a Java applet, and thus provides the user with enhanced interactive capabilities. Using this map, a user can pan and zoom to a very high level of detail and choose a very small geographic area. Note that your Web browser must be able to support Java to use this map.

• Equatorial Map: Use this option if your browser is unable to support Java. Search areas are defined by clicking on two points to build a bounding rectangle around your region of interest.

• Global Search: Use this option for a search of all latitudes and longitudes (+90 to -90 lat, +180 to -180 long).

• Stereographic N-Pole, or Stereographic S-Pole: Use this option if your browser is unable to support Java. Search areas are defined by clicking on two points to build a bounding rectangle around your region of interest.

• Global Granules Only : Use this option if you want to search for data that covers the entire globe. Note that this is NOT the same as a global search.

• Type in Lat/Lon Range: Enter latitude and longitude values in the type-in boxes. To display your defined region on the map click the Display lat/lon range on map button.

• Type in Path/Row Range: These entries are used specifically for Landsat searches. Path/row is based on the Worldwide Reference System (WRS), a global notation for locating Landsat scenes. WRS-1 is used with Landsat 1,2, and 3. WRS-2 is used with Landsat 4-7. WRS enables a user to locate Landsat imagery by specifying a scene center designated by Path and Row numbers.

  WRS-1 notation assigns 251 paths, starting at 001 and increasing from east to west. WRS-2 notation uses 233 paths starting at 001 and also increasing from east to west. Both notations use 248 rows, which refer to the latitudinal center line of the Landsat scene.

• Type in Lat/Lon Point: Use this option to enter a single point. After entering the latitude and longitude you can display the point on the map by clicking the Display lat/lon point on map button.

Choose a Date/Time Range

EDG supports both Standard and Julian date formats. Standard format requires year, month and day of the month to be specified. Julian format requires the year and day of the year. Use the buttons provided to choose the desired format.

Enter the start date and time in the text boxes indicated. Dates may be entered either in YYYY-MM-DD format (e.g., 1959-04-29) or in MM/DD/YYYY format (e.g., 04/29/1959) if Standard Date Range is toggled on. For Julian Date Range, enter in YYYY-DDD format.

NOTE: leading zeroes for the day do not have to be used. For example, 2000-1 is acceptable for day 1 of 2000.

You may enter a start time and a stop time to refine your search. Any data which overlaps this time range will be selected. If you enter only a start date, then today's date will be assumed for the end date. If you enter only an end date, then a start date of 1/1/1950 (or 1950-001 in Julian format) will be assumed.

The EDG will "remember" the date range format you specified so that the results listing will have the date of data sets or granules displayed in the format chosen. In addition, the date format for the results can be changed via the customization link on the search results page.

You can also enter an Annually Repeating Time Period. If you want to see data for the same time of year for several years, you can use this option. You must enter at least one date (either a Start date or End date) to use the Annually Repeating Time Period option.

START_DAY_OF_YEAR 1 to 366 Beginning day of seasonal interest

END_DAY_OF_YEAR 1 to 366 Ending day of seasonal interest

Query is for data granules with start dates that are between START_DATE and STOP_DATE and are between START_DAY_OF_YEAR and END_DAY_OF_YEAR in whatever year. This could involve partial "seasons" (e.g., 2/1/93-2/28/95, days 1-90 would give Feb-Mar 93, Jan-Mar 94, Jan-Feb 95).

i.e. If you wanted data for the month of February for several years:

    Start date/time (GMT): Date: 1993-02-01 Time: 00:00:00
    End date/time (GMT):   Date: 1995-02-28 Time: 23:59:59
    Start Day of Year: 032 (February 1)
    Stop Day of Year:  059 (February 28)

Choose Additional Options

Maximum Number of Granules:

The maximum number of data granules to return from a Primary Data Search. For a particular search a data center may have hundreds or even thousands of data granules available. For broad, initial searches which may hit a number of data sets, it is recommended that you limit the number data granules returned for each data set to just 10. This will speed up the searching process. Once you have identified the particular data set you are interested in, if you need additional data granules, redo the data search using a higher limit.

Browse Only:

You can request that only data granules with browse products be returned. Browse products are (usually) subsampled files which will give you an idea of what the actual data looks like.

Max Search Time:

You can set an upper limit on how long your search will run. Your search will automatically stop when the maximum search time is reached, and any results obtained up to that point will be displayed. A search normally will end well before the default maximum time is reached. You can change the maximum search time to any whole number of minutes up to the default maximum.

Customize Metadata Returned:

You can customize the metadata that will be returned in your search results by clicking on the "Customize" button. For customization you can select the attributes that you want returned, you can request the default metadata, or you can request that all of the metadata be returned in your search results. In the case you request all, a large volume of data may be returned.

Day/Night:

For non-MODIS data granules:

Day Only: Return granules that were collected during daylight, or that were collected over a long enough period of time so that the satellite track traversed both day and night.

Night Only: Return only those granules that were collected during night, or that were collected over a long enough period of time so that the satellite track traversed both day and night.

Day/Night: No constraints; return all granules.

For MODIS granules:

Day Only: Return granules obtained from all channels during daylight.

Night Only: Return granules obtained only from the Infrared channels during night.

Day/Night: Return granules obtained from all channels with no constraint on whether the granule was obtained during daylight or night.

Query Name:

The name the system will try to give to the query when you save the query (download) to your local machine. Note, that some versions of Microsoft Internet Explorer ignore this and create their own bizarre file names.

Include Non-Spatial Granules: NOT YET IMPLEMENTED

You can request that any granules without spatial properties be returned in your search results. These results are additional to what is specified in the Choose a Time Range portion of the search form.

Include Non-Temporal Granules: NOT YET IMPLEMENTED

You can request that any granules without temporal properties be returned in your search results. These results are in addition to what is specified in the Choose Search Area portion of the search form.