Re: precision of coordinate bounds in LiveMap applet

[Jonathan Callahan <callahan@xxxxxxxxxxxxx>]

Dave,

Unfortunately, java 1.0 (necessary to run on Macs) doesn't have any
formatting like this.

However, the applet does have a javascript accessible method associated
with it called setDelta(xdel,ydel).  This will cause the handles to snap
to a grid determined by xdel and ydel.  An example is seen here:

http://tmap.pmel.noaa.gov/~callahan/JAVA/map_v3.0/LiveMap_v3.0.html

You can setImage to "Carolina coast" and see the problem you're talking
about.

Then change the Grid Spacing to ".25 X .25" to see the effect.


One of the ideas we've bandied about but never implemented is to have
the grid spacing in the applet set by the grid spacing in the data. 
That way you'd 'feel' the grid spacing of the underlying data whenever
you interacted with the map.

If you're using the LiveMap applet in the context of LAS you'd have to
find the right place to use the setDelta() method in the las.js file.


Does that help?


-- Jon


Dave Brown wrote:
> 
> Hi,
> 
> In its default state with a global map, the LiveMap applet seems to
> resolve a region picked with the rubber box to the nearest whole degree.
> The numbers that appear for coordinate bounds seem always to have a
> a single '0' after the decimal point. But if the map represents a
> smaller area of the globe, rubber box selections can result in values
> such as 44.400000000000006 N appearing in the coordinate bound text boxes.
> The complete value is not visible in the text box and particularly on
> unix systems, where the number is right-justified, it is confusing for
> the user. Am I correct that it would require mods to the LiveMap applet
> source to change this behavior? It seems that formatted output with the
> significant digits limited to 4 or 5 would be a desirable enhancement
> for these text fields.
> Any plans for this, Jon?
> Thanks,
> 
> Dave Brown
> dbrown@ucar.edu