[las_users] ArcView Gridded product enhancement request

[Jonathan Callahan <Jonathan.S.Callahan@xxxxxxxx>]

To all Ferret-savvy LAS installers,

It has recently come to our attention that the script that produces the "ArcView Gridded" product needs to be improved to handle data sources that exist on grids with irregular axis spacing.  The solution is for the las/server/jnls/arc_ascii.jnl script to be enhanced to regrid data when required.

The entry for Bugzilla #1316 (this issue) reads:

The "ArcView Gridded" product MUST be on a regularly spaced grid.  Notice that 
this ASCII product contains a header that only identifies a single 
longitude/latitude pair from which all geo-referencing is calculated:

  ncols 51
  nrows 25
  xllcorner   176.0000    
  yllcorner   48.00000    
  cellsize   1.000000   

Currently, the output produces a warning if the X and Y cell sizes differ.  I 
believe the information about cell X and Y lengths in the warning message can 
be used to coach ArcView into properly registering the data.

When the longitude or latitude axis is irregularly spaced, however, ArcView 
cannot properly register the data.  What is needed in this case is for the 
script that generates this product (las/server/jnls/arc_ascii.jnl) to check 
for irregular axes and regrid to regularly spaced axes when needed.

Perhaps it should also regrid to a square grid (equal lon/lat spacing) by 
default.

This message is going out for two reasons:  1) to alert those of you with irregularly gridded data to the problem and 2) to see if anyone out there wants to come up with an improved script to deal with this.

I'm hoping that this kind of community involvement will allow the LAS developers to spend more time focused on the core code and will also help foster an Open Source spirit amongst our users.

Thanks in advance for any contributions.


-- Jon