1、EOS Data Gateway User Training,San Francisco, CA December 2002,2,Class Structure,Purpose: To enable student to search for, evaluate, and obtain land, atmospheric, and ocean science data available via the EOS Data Information System Focus is on the primary features of EDG. We will not cover all aspec
2、ts. Class format: lectures, demonstrations, hands-on exercises, individual practice We use a “live” system. No canned or simulated demos (!),3,EOS Data Gateway: Overview,User Interface for access to the data holdings in NASAs “Distributed Active Archive Centers” (DAACs) and other data centers worldw
3、ide. EDG is NOT an HDF tool. Primary Functions Data Search and Order Search by Data Granule ID or Local Granule ID Secondary Functions (not covered in class) Summary Document Search Detailed Document Search,4,EOS Data Gateway: Architecture Overview,5,EDG Home Page,Entry point for Data Search and Ord
4、er 12 EDG installations worldwide each has its own URL, e.g. Goddard EDG is at http:/eos.nasa.gov/imswelcome Link to User Support contacts Links to information on using the system Links to data descriptions System news,6,EDG Home Page (contd),User Registration / Forgot my Password Establishes an acc
5、ount with the EOSDIS system Allows you to change your EOSDIS User Profile Saves your user preferences and most recent search criteria and results (not transferable between different EDG sites),7,Using EDG: Build a Data Search,First, some terms: Attributes: Characteristics which describe a data set,
6、e.g., Parameter, Sensor, etc. Keywords: Valid search terms recognized by EDG and the data centers, e.g., Albedo, Cloud Amount, specific data set name, etc. Filters: Terms with which a list of keywords can be narrowed, e.g., Atmospheric Chemistry, etc. Data Granule: Smallest aggregation of data which
7、 is inventoried and retrievable.,8,Using EDG: Build a Data Search,Choose search keywords Choose geographic search area Select date range (standard or julian format), and time range, if desired Select other search options, if desired Submit search,9,Using EDG: Choosing Search Keywords,Keyword Method
8、1: Data Set Lookup Type in one or more keywords separated by semi-colons Scientifically relevant data sets returned Use resulting list in its entirety, or edit as needed Search options: used to limit number of data sets returned Match ANY (“or”), Match ALL (“and”), Match EXACTLY Keyword Method 2: Ch
9、oose specific keywords from categories of attributes Keyword Dependencies: Keyword lists modified based on which keyword are chosen,10,Primary Search Attributes,Parameter A measured or derived geophysical variable represented in the dataSensor A device that transmits or records a measurable signal i
10、n response to a specific physical stimulus,11,Primary Search Attributes,Data Set A named collection of data/observations Data set ID is data center specific and determined by each data center Over 1500 data set ID valids Source The observation environment, entity, or structure that holds one or more
11、 data collection devices,12,Primary Search Attributes,Data Center Location of data archive Campaign The project or study that obtained the data Processing Level Amount of processing performed on the data,13,Extended Search Attributes,Used for search criteria that are not common across all (or most)
12、datasets Similar and related search criteria are grouped in categories 26 extended attributes categories,14,Using EDG: Choose Search Area,Orthographic Map: Click on map and drag to form desired bounding rectangle Pan/Zoom Display of roads, political boundaries, rivers, etc. Equatorial Map and Polar
13、Stereographic Maps: Click/choose 2 opposite corner points of desired bounding rectangle Type-in: (lat/long, path/row, single point) “Gazateer”: Tool to assist in finding lat/long of specific city, geographic feature, etc.,15,Using EDG: Choose Temporal and Other Options,These options not required for
14、 a search Standard or Julian date formats Adjust max number of granules to be returned in a search Adjust max time limit for a search Ask for specific types of granules Customize what metadata is returned from the search (EOS data only),16,Using EDG: Awaiting Search Results,Search Status Page Displa
15、ys list of data centers where search was sent Displays messages describing status of search, e.g. “connecting”, “searching”, “returning results” Display “partial results” Do not need to wait until all searches complete before looking at results Use “View Partial Results” link,17,EXERCISE #1: Build a
16、nd Submit a Search,You are interested in land surface data anywhere over the entire globe You want specific data sets: LANDSAT-7 LEVEL-0R WRS-SCENE V002 MODIS/TERRA VEGETATION INDICES 16-DAY L3 GLOBAL 500M ISIN GRID V003 Date/Time range: 3/21/2000 to 3/22/2000 Request 5 granules per data set to be r
17、eturned,18,Using EDG: Evaluate Search Results,From Data set Results: Read available documents List granules, customize the information displayed Save results to text file for spreadsheet use (optional) Examine attributes (Comprehensive granule info) Examine granule spatial/temporal footprint Examine
18、 “browse” (NOTE: this function available on multiple pages) “View image”: Near real-time access and download of representative image “Request sample”: Download image via FTP Store some results in your “folder” for later use (optional),19,EXERCISE #2: Evaluate Search Results,Using results from Exerci
19、se #1. Read the MODIS Vegetation Indices data summary information List the granules for all data sets returned Customize the granule list: Experiment with adding and deleting information in the list Map footprints of two MODIS granules simultaneously. Examine browse (“View Image”) for one Landsat gr
20、anule.,20,Using EDG: Data Ordering,More Terms: Shopping Cart: Place for storing and preparing granules for order Order Options: Means by which data is to be sent to the user Order Your Data Place granules in shopping cart Read and accept/reject disclaimer statements Choose order options Review and s
21、ubmit order,21,Using EDG: Data Ordering,Ordering Granules from Multiple Data Sets No need to submit first order for first data set, second order for second data set, etc. Instead, add all desired granules to shopping cart and submit as a single order EDG is smart enough to route order requests to pe
22、rtinent data center(s),22,EXERCISE #3: Data Ordering,Using results from Exercise #1. Add all MODIS granules to the shopping cart Read and accept MODIS Data Quality Summary statements Select an Order Option of your choosing. Review your order summary Do NOT submit your order,23,Data Granule ID Search
23、,Search for specific granule(s) based on DAAC-generated ID numbers Building a Data Granule ID Search Access search form from “Search Types” link Required search criteria: Data set(s), type in data granule IDs Only selected data centers support Data Granule ID search Evaluate results via methods desc
24、ribed earlier,24,Other EDG Functions,User Preferences: Configure how you want defaults set, information displayed, etc. Help: Specific page help via link on blue-toned left side of every page in EDG Submit comments/questions,25,Common Errors,Didnt fill in all information on form “Jumping” ahead befo
25、re a page loads completely Account deleted. User needs to re-register Session expired due to lack of activity. Start a new session,26,Some Messages from Searches,Negative Search Results No match found Search too broad; narrow spatial and/or temporal criteria Data not found due to spatial and/or temp
26、oral limitation System ProblemsPertinent inventory system unavailable System error: please try again later Data center not responding to query; may be experiencing computer or network problems; try search again later.,27,Some Helpful Hints,Navigation Use the links along left side of each page “Jump” Menu (bottom of each search page): Move to various pages without first going back to main search page Save/Upload a search to/from your local machineWhat do I do if I dont find data? Expand your search area Increase number of granules returned Submit a question,
