[GRASS-user] Map Collars (missing attachment)

[Hamish]

> some time ago, Chris wrote:
> > The first issue to tackle is to remove the collars of the NOAA charts.
> > I've searched the archives and there are only two dated posts and both
> > recommend shapefiles. Well there are no shapefiles for the Atlantic or
> > other water bodies so this method cannot work.

Hamish:
> I'm not sure how that's supposed to work, but FWIW you might try the
> NOAA coastline extractor or the v.in.gshhs addon module to get the
> Atlantic coastline as a vector map.
> 
> > If anyone has any suggestions or ideas it would be greatly
> > appreciated on how to remove map collars of NOAA charts. 
> 
> the attached script is probably very far from the fastest way to do it,
> but it works on the test map I tried (NOAA #12200). maybe the salmon
> color needs to be a bit more fuzzy to cover different maps?
> probably some maps have more than single pixel specks to be removed,
> so r.neighbors window size could be upped.

(or make the resolution 2x as coarse, which would speed up processing
as well, at the cost of the edge pixels)

> the idea:
> 1) download RNC maps from NOAA's website
> 2) Convert BSB format to GeoTIFF with gdalwarp
> 3) Import GeoTiff into GRASS
> 4) remove any single pixel specks from the map
> 5) temporarily mask out white, black, salmon colored metacontent which
>    occurs in the collars
> 6) zoom to the extent of the color-masked map
> 7) save a copy of the original chart using the smaller bounds to GeoTIFF
> 8) ... tile GeoTIFF as needed for MapServer/WMS or GpsDrive application
> 9) go sailing
....
> -----Inline Attachment Follows-----


hmmm, the shell script attachment seems to have been removed at some point.
Did the listserv settings change? Chris, did you get it via the cc?


cut&pasted:  (hopefully yahoo's completely fubar'd mail servers of late
do not randomly line wrap it too badly)

decollar_noaa_charts.sh
-----------------------
r.in.gdal in=./BSB_ROOT/12200/12200_1_merc.tif out=noaa_12200

MAP="noaa_12200"

g.region rast="$MAP"

# check that we are dealing with a paletted map
eval `r.info -t "$MAP"`
if [ "$datatype" != "CELL" ] ; then
   echo "ERROR: only categorical maps can be processed"
fi


# find cats in map
CATS=`r.category $MAP`

# find black and white category numbers
unset BLACK WHITE SALMON
for CAT in $CATS ; do
  RULE=`r.what.color in="$MAP" value="$CAT"`
  echo "$RULE"
  COLOR=`echo "$RULE" | cut -f2 -d' '`
  if [ "$COLOR" = "0:0:0" ] ; then
     BLACK="$CAT"
  elif [ "$COLOR" = "255:255:255" ] ; then
     WHITE="$CAT"
  elif [ "$COLOR" = "219:73:150" ] ; then
     SALMON="$CAT"
  fi
done
echo "black is $BLACK, white is $WHITE, salmon is $SALMON"

REMAINING=`echo $CATS | tr ' ' '\n' | grep -vw "$BLACK\|$WHITE\|$SALMON"`

#### setup temporary file
TMP="`g.tempfile pid=$$`"
if [ $? -ne 0 ] || [ -z "$TMP" ] ; then
    g.message -e "Unable to create temporary files"
    #exit 1
fi

echo "$BLACK = NULL" > "$TMP"
echo "$WHITE = NULL" >> "$TMP"
echo "$SALMON = NULL" >> "$TMP"
for CAT in $REMAINING ; do
   echo "$CAT = $CAT" >> "$TMP"
done


# remove stray single dots
r.neighbors in="$MAP" out="$MAP.despeckle" method=mode

# make a reclass map, setting black and white to NULL
r.reclass in="$MAP.despeckle" out="$MAP.filtered" rules="$TMP"

g.region zoom="$MAP.filtered"
r.mapcalc "$MAP.cropped = $MAP"

r.mapcalc "$MAP.cropped = $MAP.filtered"

## debug method for finding residuals
#r.mapcalc "$MAP.cover = 1"
#g.region rast="$MAP"
#r.mapcalc "$MAP.residual = if($MAP.cover == 1, null(), $MAP)"
#r.stats -c "$MAP.residual"
## single 6,8 dot
#d.zoom to collar which should be empty
#r.univar $MAP
#r.out.xyz $MAP
#echo "symbol basic/star 20 -72.35262972 38.8881031 black blue" | d.graph -m
#echo "symbol basic/star 20 -74.51749113 39.27423606 black aqua" | d.graph -m

r.out.gdal in="$MAP" out="$MAP_decollared.tif" type=Byte #...




Hamish