This is an interactive Java Applet to visualize monthly Geoid differences.
Firefox, Mozilla, MS Internet Explorer are recommended browsers.
To use it, you must enable Java for your browser, and your local firewall must not block the connections
to the server 'icgem.gfz-potsdam.de' on port 1891.
Please have some seconds patience for loading the applet.
You can select monthly solutions one of the three processing centers (GFZ, JPL, CSR) or weekly solutions (only GFZ),
each with 5 different filter sets (DDK1...DDK5, for weekly only DDK1...DDK3 are present), or 'unfiltered'.
As reference model in all cases 'eigen-6s' as static satellite-only model is subtracted.
The lm-range of the display is truncated to l = [3,...,90].
Press the top right 'animate'-button
to start the time animation.
It shows a time sequence of monthly
undulations of the geoid, starting in 2003 (not all months are available).
Press then 'stop' to pause the animation. Also interactive browsing in time is possible (see below).
In the right bottom corner of the view a schematic clock displays year and first day of the actual shown solution.
With the arrow keys (→, ←, ↑, ↓), together with 'Alt'-key, you can move around in time (see below).
You also have many options to change grid resolution, viewpoint, zoom, light source parameters ...
See below the applet for a detailled usage info.
Most buttons (or the button-labels) have a help option: if you move the mouse cursor
over it, a small popup will explain its function.
The Earth can be rotated either with mouse cursor dragging (sometimes a bit slow)
or the keyboard actions (see below).
This choice selects monthly models of one of the three processing centers (GFZ, JPL, CSR) or GFZ weekly solutions
This choice selects one of 5 filter methods (DDK1, , DDK5) or 'unfiltered'.
DDK1 uses the strongest filter, and DDK5 the weakest.
2003001 (or similar)
This choice displays all available models for the given selection of processing center and filter
method in the format 'yyyyddd'. By selection you can directly display of one of them.
Selects maximal used degree of model spherical coefficients (range 10..90)
With these two button you can zoom and unzoom your region of interest.
Before you do this, move it into the center of view, as described below (keyboard actions).
boost Sets the 'exaggeration factor' i.e. 'boost = 10000' means
that 1m of geoid undulation is displayed as 10km high mountain.
grid Set the grid resolution in [°].
The smaller the value, the more details become visible (depending on lmax).
Toggles between two display modes. If it is 'off' you will see
the discretizing triangles of the grid, else the colors inside the triangles are interpolated.
Toggles simultaneous display of back-side of the Earth
This button lets the Earth rotate around its polar-axis.
(Press then to stop it)
Pops up a new window to set some light control variables (position, focus parameter 'gamma').
Starts (or stops) animation of time sequence of models
Popup a new visualization frame which can be moved and zoomed synchronously with the current view
Please note, that the Applet must have the focus for keyboard actions!
The arrow keys (←, →, ↑ ↓) can be used to move the Earth.
The arrow keys with "Alt" can be used to change the model-time: '←' and '→' shift one month/week,
while '↑' and '↓' shift one year (actually jump ±1 resp. ±12 models back or forward).
The key '0' jumps back to the first available solution of the sequence
Pressing the arrow-keys ↑ and ↓ with "Ctrl":
will change the colormap scale-factor (always by a factor of √2),
and ← → modify the exaggeration factor (boost) by a factor 2.
The +,- or <, > keys can be used for zooming/unzooming.
(Some browsers seem to ignore these keys sometimes, however the +/- keys on the numeric keypad should always work)
The p-key toggles display of plate-boundaries.
There are some other keys (s,o,c,h,b) to select other background images.