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ngEO Browse Server - Architecture

ngEO Browse Server

• Entirely based on Open Source Software
• OGC's WMTS and WMS Standards
• Configuration from ngEO Controller
• Data ingested by ngEO FEED
• Authentication using Shibboleth
• Authorization from ngEO Web Server

Preprocessing

• Input Geographic Metadata for Geo-referencing
• Footprint polygon
• Regular grid of tiepoints
• Pre-georeferenced images
• Optimizations
• Footprint generation
• Re-projection
• Addition of alpha-channel
• Internal tilling
• Overviews
• Compression

MapCache Enhancements

Time dimension support

    ...
    
        /var/ngeob_data/mapcache.sqlite
        select strftime('%Y-%m-%dT%H:%M:%SZ',start_time)||'/'||strftime('%Y-%m-%dT%H:%M:%SZ',end_time) from time where source_id=:tileset and start_time<=datetime(:end_timestamp,'unixepoch') and end_time>=datetime(:start_timestamp,'unixepoch') and maxx>=:minx and maxy>=:miny and minx<=:maxx and miny<=:maxy order by end_time limit 100
    

                        

Visual representations of search results e.g. single browses or all browses in a specific time interval

Read-only functionality

    ...
    true

                        

Absent tiles are considered empty instead of being sent to WMS for generation

Configure max-cached-zoom

    ...
    
        WGS84
    

                        

Dynamically create high resolution tiles from lower resolution ones

Storage optimization e.g. detect_blank

    foss4g.sqlite
    true

                        

9 bytes stored per tile (hex quadruplet). Dynamically returned as a 132 byte PNG.

Demonstration

Live

Time Slider

Entire Dataset

Nottingham

max-cached-zoom