Hi all

I was just trying to make a new header definition that could report appropriately, dependant on presence of a coordinate system, plan, extended or projected elevation.  It was mostly progressing OK until I realised I was pinning my hopes on using the metapost ATTR__elevation variable in a block of tex code.  That and my very poor grasp of tex Boolean testing (   \if ATTR__elevation  is probably the wrong syntax) mean that I am probably doomed to fail. Since I have got this far, I may as well ask a few questions….

In the code below…

Is there a tex variable equivalent to the  ATTR__elevation metapost variable?

Is it possible to differentiate extended elevations from projected elevations (and plans) with tex?

For example, can we determine the projection angle of a projected elevation?

How to format the magdecl output to just 1 decimal place?

Bruce

# % print coordinate system and projection related information

\if ATTR__elevation  % print elevation specific text %THIS TEST ALWAYS FALSE??

# % extended elevation

                {\the\legendtextsize\ss {Idealised elevation} \par} %' looking generally East' %this whole line probably redundant

# % projected elevation

    \edef\tmp{\the\outcsname} \ifx\tmp\empty %ie if no cs

                  {\the\legendtextsize\ss {Elevation looking xxx deg magnetic}\par} %NEED TO SEE IF PROJECTION ANGLE AVAILABLE TO TEX

                \else                                    %there is a cs

      {\the\legendtextsize\ss\the\outcsname { elevation looking xxx deg}\par} %NEED TO SEE IF PROJECTION ANGLE AVAILABLE TO TEX

    \fi

  \else % not ATTR__elevation % print plan specific text

# % plan              

    \edef\tmp{\the\outcsname} \ifx\tmp\empty %ie if no cs

                   %{\the\legendtextsize\ss {Plan projection (not georeferenced)}\par}  %remove preceding % for redundant long form

                                {\the\legendtextsize\ss Arrow points to magnetic north}

                \else                                    %there is a cs

                                \the\legendtextsize\ss\the\outcsname %{ plan projection}\par %remove preceding % for redundant long form

                                \edef\tmp{\the\northdir} \ifx\tmp\empty \else

                                                {\the\legendtextsize\ss { arrow points \the\northdir { north}}} % grid or true north

                                \fi          

# % Could report declination here            

        \edef\tmp{\the\magdecl} \ifx\tmp\empty \else

{\the\legendtextsize\ss\the\magdecl { deg magnetic declination}\par} %HOW TO LIMIT TO ONE DECIMAL PLACE?

        \fi 

                \fi                          

  \par\par             

  \fi % ATTR__elevation % end plan

Above code produces the top couple of lines of this header snapshot.  It should be different depending whether it is a plan or elevation, but at present is always this way.  However the coordinate system test does work properly.