OB_CLOUD Data Browser |

The OB_CLOUD Data Browser is a tool for browsing the Ocean Biology OB.DAAC satellite data which resides in the NASA Earthdata cloud. This tool interfaces with the Harmony Search Service and leverages CMR (Common Metadata Repository) for granule-level metadata retrieval.

Location:

• Menu > Earthdata-Cloud > OB_CLOUD Data Browser

• (Preferences): Menu > SeaDAS > Settings > Seadas Toolbox > Earthdata Cloud

Features:

• Mission-aware metadata filtering using satellite/instrument, data level, and product names.

• Mission-aware metadata filtering using satellite/instrument, data level, and product names.

• Integrated spatial and temporal filters, with automatic date validation based on mission-specific coverage.

• Day/Night granule selection, supporting all CMR day_night_flag values.

• Granule preview support, with hover-based thumbnail loading from browse_images, and full-resolution image viewing.

• Granule pagination and result management, decoupling total fetch limit from per-page display.

• Secure file downloads with Earthdata login support and progress monitoring.

Product-Mission Criteria

The search for satellite data can be restricted to a specific satellite mission, data level and product.

• Satellite/Instrument

This is what is commonly referred to as the satellite mission. Note that for certain sensor designs, (for instance VIIRS, MODIS, OLI, OLCI, etc.) there can be multiple missions. This is usually delineated and contained in short form in the satellite mission name.

For example:

- 'MODISA'

Refers to the 'MODIS' sensor that is mounted on the 'Aqua' platform.

- 'MODIST'

Refers to the 'MODIS' sensor that is mounted on the 'Terra' platform.

- 'PACE_OCI'

Refers to the 'OCI' sensor that is mounted on the 'PACE' platform.

- etc.

Note: you can only select one mission ('Satellite/Instrument') per search. This is because the data levels (and especially the products) are specific to each mission, and those selectors are dynamically configured based on the mission you choose.

• Data Level

This is the science processing level of the data.

• Product

This is the specific product of the data.

Temporal Filter

The search for satellite data can be restricted based on a time period. Included within this are options to restrict based on whether the data was imaged in the daytime or nighttime.

• Start Date

This is the start date of the data. If this is field is left blank then no start date restriction is applied (effectively meaning the start of the mission).

• Stop Date

This is the stop date of the data. If this is field is left blank then no stop date restriction is applied (effectively meaning the current date).

Temporal Filter: Day/Night

These are the options to restrict based on whether the data was imaged in the daytime or nighttime.

• Day

Search only retrieves data which was imaged in the daytime.

• Night

Search only retrieves data which was imaged in the nighttime.

• Both

Search is not restricted to daytime or nighttime data and allows both.

Spatial Filter

The search for satellite data can be restricted to a user specified geographic region of interest. This is done through parameters known as a geographic 'bounding_box', which is defined by the fields: 'North', 'South', 'West' and 'East'. The search will only return satellite data files which match in part or in full the user requested bounding_box.

Keep in mind that satellite data (such as unprojected level-2 data) is oriented to the actual observation of the earth made by the satellite, and is not generally precisely represented by a North, South, West, East bounding box. So this can result in extra files being returned by the search which do not actually have data in the user requested bounding box.

• North

Northernmost latitude relative to requested region
(used in field 'bounding_box' of API)
Default is effectively 90.0

• South

Southernmost latitude relative to requested region
(used in field 'bounding_box' of API)
Default is effectively 90.0

• West

Westernmost longitude relative to requested region
(used in field 'bounding_box' of API)
Default is effectively -180.0

• East

Easternmost longitude relative to requested region
(used in field 'bounding_box' of API)
Default is effectively 180.0

Spatial Filter: Formatting

The internal format which is ultimately used for the spatial fields is the numeric decimal format. However, the browser tool will accept and convert most any format.

The following table illustrates the full list of optional formats (shown in example for a sample point in the Chesapeake Bay).

Format | Lat | Lon
--- | --- | ---
Decimal_Degrees (Numeric) | 37.85 | -76.15
Decimal_Degrees (Compass) | 37.8°N | 76.15°W
Degrees (Numeric) | 37° | -76°
Degrees (Compass) | 37°N | 76°W
Degrees_Minutes (Numeric) | 37°48′ | -76°6′
Degrees_Minutes (Compass) | 37°48′N | 76°6′W
Degrees_Minutes_Seconds (Numeric) | 37°48′00″ | -76°6′00″
Degrees_Minutes_Seconds (Compass) | 37°48′00″N | 76°6′00″W

Note: for the format of minutes and seconds: the single quote and double quote characters can optionally be used instead of the alphanumeric prime characters.

Spatial Filter: Accessory Tools

There are several accessory fields which can aid in populating the 'North', 'South', 'West' and 'East' fields. These fields themselves are not actually used in the search, but only to populate the mentioned bounding box fields.

• Coordinates

This is a single coordinate point (latitude longitude) to serve as the center of the scene. The 'Box Size' is used in combination with the 'Coordinates' to populate the 'North', 'South', 'West' and 'East' fields.

• Box Size

This is size of the region (in degrees). The 'Box Size' is used in combination with the 'Coordinates' to populate the 'North', 'South', 'West' and 'East' fields.

The options are:

- Box Size = [Number]

This value defines the width and height (in degrees) of the region which is centered on the value in the 'Coordinates' field. (See Example 1 below).

- Box Size = [Dimension] (lon x lat)

This two-dimension value (format lon x lat) defines the width and height (in degrees) of the region which is centered on the value in the 'Coordinates' field. (See Example 2 below).

• Preset Locations

This selector contains pre-defined stored geographic locations. Each entry is a single point location, defined by a location name and it's associated coordinates. Selecting a location will then load the value into the "Coordinates" field. The loaded 'Coordinates' field, in combination with the 'Box Size', will then automatically update the 'North', 'South', 'West' and 'East' fields.

For reference: the non-editable configuration file which contains the 'Preset Locations' is:

~/.seadas/auxdata/regions/locations.txt

Spatial Filter: Examples

A few examples illustrating the how the 'Preset Locations', 'Coordinates', and 'Box Size' fields combine to auto-populate the 'North', 'South', 'West' and 'East' fields.

Example 1 Setting 'Box Size' with a single number In this example the user sets the 'Box Size' and the 'Coordinates'. The 'North', 'South', 'West' and 'East' fields then get auto-filled. Here the 'Box Size' is set to a number ('1') and the 'Coordinates' are also set. Then the 'North', 'South', 'West' and 'East' fields get auto-filled. A 'Box Size' of '1' means that the box will span west-east by 1 degree and span north-south by 1 degree centered about the 'Coordinates'. Hence: ◦ 'North' is set to the lat of 'Coordinates' plus 0.5 degrees ◦ 'South' is set to the lat of 'Coordinates' minus 0.5 degrees ◦ 'West' is set to the lon of 'Coordinates' minus 0.5 degrees ◦ 'East' is set to the lon of 'Coordinates' plus 0.5 degrees

Example 2 Setting 'Box Size' with a two-dimension number In this example the user sets the 'Box Size' and the 'Coordinates'. The 'North', 'South', 'West' and 'East' fields then get auto-filled. Here the 'Box Size' is set to a number ('1x2') and the 'Coordinates' are also set. Then the 'North', 'South', 'West' and 'East' fields get auto-filled. A 'Box Size' of '1x2' means that the box will span west-east by 1 degree and span north-south by 2 degrees centered about the 'Coordinates'. Hence: ◦ 'North' is set to the lat of 'Coordinates' plus 1 degrees ◦ 'South' is set to the lat of 'Coordinates' minus 1 degrees ◦ 'West' is set to the lon of 'Coordinates' minus 0.5 degrees ◦ 'East' is set to the lon of 'Coordinates' plus 0.5 degrees

Spatial Filter: Custom User Locations and Regions

The user can define their own locations and regions with two optional selectors ('User Locations' and 'User Regions') which are available in the preferences. Locations are defined as single point coordinates whereas 'Regions' are defined as geographic areas with 'North', 'South', 'West' and 'East' bounds.

• User Locations

Selecting the user-defined 'User Locations' will set the "Coordinates" field, which in turn will set the North, South, West and East fields.

- To enable the 'User Locations' selector

The 'User Locations' field is not available by default, but can easily be added by going to the Preferences page:
(Menu > SeaDAS > Settings > Seadas Toolbox > Earthdata Cloud)
and checking "Include 'User Locations' Selector".

- To edit the 'User Locations' selector

Entries can be added to the 'User Locations' selector by manually editing the following file:
~/.seadas/auxdata/regions/user_locations.txt.

Here's a sample of the formatting in the 'User Locations' configuration file:

    #  Name = Lat Lon
    #  (coordinates can be space and/or comma delimited)

    My Sample Location = 37°48′00″N, 76°6′00″W

• User Regions

Selecting the user-defined 'User Regions' will directly populate the North, South, West and East fields.

- To enable the 'User Regions' selector

The 'User Regions' field is not available by default, but can easily be added by going to the Preferences page:
(Menu > SeaDAS > Settings > Seadas Toolbox > Earthdata Cloud)
and checking "Include 'User Regions' Selector".

- To edit the 'User Regions' selector

Entries can be added to the 'User Regions' selector by manually editing the following file:
~/.seadas/auxdata/regions/user_regions.txt.

Here's a sample of the formatting in the 'User Regions' configuration file:

    #  Name = North  South  West  East
    #  (coordinates can be space and/or comma delimited)

    My Sample Region = 39°36′00″N, 35°54′00″N, 77°30′00″E, 74°18′00″E

Search

The bottom row of buttons controls the execution of the search and how the results are displayed.

• Max Results

This field limits the maximum number of file names returned by the search.

• Results Per Page

This field set the maximum number of returned file names per page.

• Search

This button executes the data search.

• Cancel

This button cancels and closes the OB_CLOUD Browser form.

• Help

This button links to the OB_CLOUD Browser help page.

Results

The search is displayed in table form. Hovering over each filename in the results table, a preview image of the file is displayed if an image preview is available for the file.

• Filename

This is the name of the file.

• Download File Checkbox

Selecting this adds it to the files to be downloaded. Multiple files can be downloaded at once.

• Files Found

The is the total number of files found.

• Previous - Next

This advances to the previous and next pages.

• Subset

This tool is under-construction for a future SeaDAS release. It will make a subset of the selected files.

• Download

This opens a file finder window for saving the downloads directory. All files will be downloaded into a single directory.