Post on 20-Jan-2016
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Polar Mapping Prototyping and the Lessons Learnt
Shinobu KawahitoRemote Sensing Technology Center of Japan (RESTEC)in support of Japan Aerospace Exploration Agency (JAXA)
WGISS-28 Pretoria
Overview of the Prototype
• OGC/WMS and other related standards based web mapping
system• Interactive with distributed WMS servers • Serve images in polar specific projections
System Features
User Friendly
• The image applied in this prototype focuses on “temperature”(to show Snow extent, Sea ice extent, etc)
Mapping Theme
• Easy to compare multiple images • Easy to view time dependent variations and to select a date of
interest
System Designing User Friendly GUI design
(Requirements) • Multiple images be compared easily
(Solution) • Adjustable image transparency was introduced.
Each of multiple images is sent independently for GUI (not combined
beforehand to one image) thereby allowing the GUI to change their
respective transparency to answer the needs on the spot.
(Requirements) • Time sequential changes be shown easily and a date of interest be
specified on the spot.
(Solution)• Added an indicator to “Date Control” for this purpose.
Snapshot
Snapshot
Create One Final Overlaid Image
Role of Tiers in producing an Overlaid Image
GUI WMS Client WMS Servers
AMSRImage (IC)
Others
Transparency fot the three middle images is variable.
+
+
+
Maps+
Overlay in WMS Client
AMSRImage (SWE)
AMSRImage (SST)
AMSRImage (IC)
Others
Maps
AMSRImage (SWE)
AMSRImage (SST)
Create Five Independent Images
Overlay in GUI
Top Layer( Vector Maps )with transparent background
2nd Layer( Daily AMSR-E IC )with transparent background
3rd Layer(Daily AMSR-E SWE)with transparent background
4th Layer(Daily AMSR-E SST)with transparent background
5th Layer(Other Images)
Overlaid Image
Overlay in GUI - Five Map Layers and Data Categories
Findings and Lessons Learnt
• WMS servers which support OGC/SLD will change styles
(width, color, symbol, etc) of features (points, lines, etc)
dynamically answering user’s requests. Images from different
resources can be harmonized by utilizing this ability.
Better Portrayal with WMS + SLD
Original image provided by an NSIDC server
Changes made on some features to follow SLD requests
Findings and Lessons Learnt (cont’)
• Evolved Web browsers and RIA allow various system
configurations for performing interactive mapping and portrayal. - The portrayal includes : overlay images, draw lines, place marks,
draw graphs ..- The tier to perform portrayal:
▪ Server-sides are capable of complicated portrayal, but not so
responsive to interactive manipulations as they should be.▪ GUI-sides provides a quick response once the required data are
ingested, but may spend more time in retrieving the data.
In which tier the portrayal be made
• Projection conversion is a merit of WMS, but it may collapse
some of the appearances; strings labeled to images in
particular.
Images containing a label
Findings and Lessons Learnt (cont’)
• For time-series dataset such as AMSR-E daily data, a problem arises to decide
which names shall be applied to <Layer>; dataset name or name of each data? - When dataset name is applied, GetMap requests will have a difficulty in
identifying each of the data (such as partial scenes) unless vendor-specific
parameters are used additionally.- When data name is applied, all the information must reside in a single
document, which is not practical when a large number of data are applied in
WMS servers.• In our prototype, AMSR-E IC (SWE, SST) has only one image per day. So, we
have assigned dataset name to <Layer>, while Time parameter is used to
identify each of the daily images in issuing/parsing a GetMap request.
• Further, each <Layer> can contain items such as <MetadataURL>,
<DataURL> which help in describing data and accessing real data. Dataset
level or data level of these items should be consistent with the level of <Layer>.
“Capabilities Document” ( = WMS/GetCapabilities response in XML)