let's standardize sites

[David Gerdes]

mccauley at ecn.purdue.edu wrote:

> Does anyone have a problem with the
> easting|northing|elevation|#category attribute_label
> format? It sounds okay to me.


- I like the suggestion to add the elevation field.
- The #category field should remain optional!
- The user should be able to interpolate on data which is 
    in the <attribute_label> field or in the elevation field.
   - we might want to add a function that programs can use if desired
     to parse the attrlabel string for fields of numeric data and which
     allows the user to specify which field of data they are interested in.
     (of course ultimately this should be handled by the dbms but it is
     still very useful if you want to avoid a database)
- We should develop a set of routines to parse the fields for the programmer 
    so that we get a standard interface. [G_get_site ()]



You also said:

> In terms of storage space, this only adds another character (one byte)
> for each site to existing site lists to make them compatible, so this
> is not a big negative (<=5% increase in storage requirements).

This makes me think that you want to change all existing site files.
There is no reason to.  Because what you said:

> If we included this extra field, it would have to remain
> optional (i.e., G_get_site (fd, &e, &n, &z, &str) > 0 if
> the third field is blank).
> 

is true even for the current format.  If there are only 2 pipes (|)  then
G_get_site can be smart enough to correct for this. (that is unless 
<attribute_label> has pipes in it.


Furthur ruminations produced:

How about a format like:
<easting>|<northing>|[z|[d4|]...][#category_int] [attr_text OR %flt[%flt]...]


where 
    []  =  optional. 
    ... = optionally repeate
    |   = dimension suffix
    #   = category prefix
    %   = float data prefix

this allows for N dimensional sites, an optional 
category number, and an optional text attribution OR any number of floating
point numbers 

OR we could provide for text AND floats to be allowed if desired.

-- 
  David Gerdes
  US Army Construction Engineering Research Lab
  Spatial Analysis & Systems Team
  dpgerdes at zorro.cecer.army.mil