[GRASS-dev] [GRASS GIS] #87: GIS.m: Fancy Map Display statusbar coords in Lat/Lon

[GRASS GIS]

#87: GIS.m: Fancy Map Display statusbar coords in Lat/Lon
-------------------------+--------------------------------------------------
 Reporter:  hamish       |       Owner:  grass-dev at lists.osgeo.org
     Type:  enhancement  |      Status:  new                      
 Priority:  minor        |   Milestone:  6.4.0                    
Component:  Tcl          |     Version:  unspecified              
 Keywords:               |  
-------------------------+--------------------------------------------------
 This was code request # 401 over at the old Gforge bug tracker. Moving it
 here.
 http://wald.intevation.org/tracker/index.php?func=detail&aid=401&group_id=21&atid=188


 ----
 Hi,

 I would love for Lat/Lon locations to format the Map Display statusbar x,y
 string into 45°59.9999'S  170°59.9999'W.

 Hamish:
 {{{
 >>>        set mapunits [MapCanvas::get_mapunits]
 >>>         if { [string first "degree" $mapunits ] >= 0 } {
 >>>             set outfmt_coords {%.6f}
 >>>         } else {
 >>>             set outfmt_coords {%.3f}
 >>>         }
 }}}
 Michael:
 > > This is a procedure I didn't know about. Did you write it? Seems
 > > handy. I might write something similar in wxgrass.
 H:
 >> Yes, I wrote it to stabilize the x,y coords in the bottom right corner
 >> of the GIS.m Map Display window. I would love for Lat/Lon locations
 >> to munge the string into 45°59.9999'S  170°59.9999'W.
 M:
 > Why can't this just be built into your get_mapunits procedure? I can add
 it
 > to the statusbar easily enough.

 because that calls g.proj to get the units. You only need to do that once
 at init to set a global variable. You really don't want to be calling a
 module twice every time the mouse moves 1 pixel.

 Python/SWIG:
 {{{
 # test the string made by   (eg "degrees")
 python_grass6.G_database_unit_name(int plural)   # ie 0 or 1
 }}}

 > BUT is there a way to get the degree symbol that works on all platforms?

 Does this show a degree symbol on the Mac?
 {{{
 $ echo "puts \xB0; exit" | wish
 }}}


 here is some non-functional demo Tcl code:
 {{{

 init {
    global is_ll
    set mapunits [MapCanvas::get_mapunits]

    if {string first "degree" $mapunits ] >= 0 } {
       set is_ll 1
    } else {
       set is_ll 0
    }
    if { is_ll } {
        # failsafe, will try for fancy fmt later
        set outfmt_coords {%.6f}
    } else {
        set outfmt_coords {%.3f}
    }
 }


 .....
 bind $can($mon) <Motion> {
   global mon
   global is_ll

   set scrxmov %x
   set scrymov %y
   if { is_ll } {
      set eastcoord  [fmt_latlon [eval MapCanvas::scrx2mape $mon %x] 0]
      set northcoord [fmt_latlon [eval MapCanvas::scry2mapn $mon %y] 1]
   } else {
      set eastcoord  [format $outfmt_coords [eval MapCanvas::scrx2mape $mon
 %x] ]
      set northcoord [format $outfmt_coords [eval MapCanvas::scry2mapn $mon
 %y] ]
   }
   set coords($mon) "$eastcoord $northcoord"
 }
 ......



 proc fmt_latlon { num, is_latitude } {
      global is_ll
      # units are degrees
      # _d means integer, _f means float
      set deg_d [expr num - (num%1) ]
      set min_f [expr (num%1)*60 ]
      set min_d [expr min_d - (min_d%1) ]
      set sec_f [expr (min_f%1)*60 ]

      if { is_latitude } {
        if { num > 0 } {
           set hem_str "N"
        } elif { num == 0 } {
           set hem_str ""
        } else {
           set hem_str "S"
        }
      } else {
        if { num > 0 } {
           set hem_str "E"
        } elif { num == 0 } {
           set hem_str ""
        } else {
           set hem_str "W"
        }
      }

      set num_fmt [concat [format {%3d} deg] "\xB0" \
         [format {%02d} min_d] {'} \
         [format {%.5} sec_f]  {"" } $hem_str ]

     return num_fmt
 }

 }}}


 Hamish
 ----

 Date: 2007-05-22

 Sender: Hamish B

 slight adjustment:

 > set coords($mon) "$eastcoord $northcoord"

 move that into the {is_ll} bit and if LL put $northcoord first.


 Hamish

 ----

 I guess if the degree symbol is not portable for display a "d " or just a
 space could be used, but its not as nice.


 Hamish

-- 
Ticket URL: <http://trac.osgeo.org/grass/ticket/87>
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