Sandbox WEB

Title: ESIP_CF NetCDF - X3D example of Field Of Regard swath definition

In the 2013-10-08 ESIP Winter Meeting briefing: 'CF Unleashed ESIP Winter 2013.pptx' briefing, Aleksandar Jelenak referenced the following graph to illustrate a major challenge incorporating descriptions of satellite swath data into a CF-Compliant NetCDF markup.

During the Feb-2013 ESIP-CF Telecon one of the possibilities discussed for standardizing the markup for the repeating Field Of View (FOV) footprints within a swath scan's Field Of Regard illustrated in IASI_AMSU_SCAN.gif was to use a 3D markup standard such as X3D. The snippit of X3D code listed below illustrates the process of defining a FOV instance then referencing this instance within various transformation groups to depict a standard swath scan.

The following code illustrates a swath of four 2x2 matrices of FOV cones. The first fov transformation group is defined as a named instance, and the three remaining FOVs are defined by embedding the named instance inside new transformation groups. Once a group containing the 4X4 scan patterns is created, this instance can then be replicated as many times as is necessary to describe an entire swath scan (4 times in this example).

X3D Code

<Transform DEF="FOV4_SWATH1_TRANSFORM" rotation="0.000000 1.0 0.000000 0.000087267">

<Group DEF="FOV_4X4">

<Transform DEF="FOV1_TRANSFORM" rotation="0.000000 0.70710678 0.70710678 0.0000153">

<Group DEF="FOV_Cone">

<Shape>

<Appearance/>

<IndexedFaceSet coordIndex="5 4 6 -1 0 4 1 -1 4 0 6 -1 1 4 2 -1 3 4 5 -1 2 4 3 -1 0 1 6 -1 1 2 6 -1 2 5 6 -1 2 3 5 -1 ">

<Coordinate DEF="FOV_Cone_coords"

point="0.000000 0.010000 -1.000000 0.008660 0.005000 -1.000000 0.008660 -0.005000 -1.000000 -0.000000 -0.010000 -1.000000 0.000000 0.000000 0.000000 -0.008660 -0.005000 -1.000000 -0.008660 0.005000 -1.000000 "

/>

</IndexedFaceSet>

</Shape>

</Group>

</Transform>

<Transform DEF="FOV2_TRANSFORM" rotation="0.000000 -0.70710678 0.70710678 0.0000153">

<Group USE="FOV_Cone"/>

</Transform>

<Transform DEF="FOV3_TRANSFORM" rotation="0.000000 -0.70710678 -0.70710678 0.0000153">

<Group USE="FOV_Cone"/>

</Transform>

<Transform DEF="FOV4_TRANSFORM" rotation="0.000000 0.70710678 -0.70710678 0.0000153">

<Group USE="FOV_Cone"/>

</Transform>

</Group>

</Transform>

<Transform DEF="FOV4_SWATH2_TRANSFORM" rotation="0.000000 1.0 0.000000 0.000029089">

<Group USE="FOV_4X4"/>

</Transform>

<Transform DEF="FOV4_SWATH3_TRANSFORM" rotation="0.000000 1.0 0.000000 -0.000029089">

<Group USE="FOV_4X4"/>

</Transform>

<Transform DEF="FOV4_SWATH4_TRANSFORM" rotation="0.000000 1.0 0.000000 -0.000087267">

<Group USE="FOV_4X4"/>

</Transform>