[GRASS-user] Re: Importing lines from database

[Hamish]

Seb wrote:
> Is this still the best solution for creating lines from a
> points ASCII file?  So assuming one has an ASCII file like:
> 
> ---<--------------------cut
> here---------------start------------------->---
> id|X|Y
> AGB-08-0001|-4.44|22.06
> AGB-08-0001|-5.90|20.17
> AGB-08-0001|-5.03|17.49
> AGB-08-0001|-5.03|18.16
> AGB-08-0002|-4.44|22.06
> AGB-08-0002|-5.90|20.17
> AGB-08-0002|-5.03|17.49
> AGB-08-0003|-4.44|22.06
> AGB-08-0003|-5.90|20.17
> ---<--------------------cut
> here---------------end--------------------->---
> 
> and we'd like to create lines for each code in the "id" column, we'd
> have to reformat the file so that it conforms to the "standard" GRASS
> format for ASCII lines files?  If so, it seems we'd also need to recode
> such an "id" column into integer, so that it can be used as category.
> Or perhaps there is a better approach to importing this kind of data
> that are typical in animal tracking studies, where coordinates
> correspond to measurements taken at sequential times for each animal
> (id)?  Thanks in advance for any input.

it's pretty easy to get that into 'v.in.mapgen -f' format, but attaching
the labels might be a pain so maybe the awk script (if you can get your
head around it) is easier way after all??.


here's a little script to do it:

# script to load in data file, then make into lines based on unique
#   first column

INFILE="animal_track.dat"
OUTFILE="animal_track.asc"
MAPNAME=`echo "$OUTFILE" | cut -f1 -d.`

#

ANIMALS=`grep ^AGB "$INFILE" | cut -f1 -d'|' | sort | uniq`
echo "nan nan" > "$OUTFILE"
\rm "${OUTFILE}.table"

i=0
for CRITTER in $ANIMALS ; do
   i=`expr $i + 1`
   grep -w "$CRITTER" "$INFILE" | \
     awk -F'|' '{print $2 " "$3}' >> "$OUTFILE"
   
   echo "nan nan" >> "$OUTFILE"

   echo "$i|$CRITTER" >> "${OUTFILE}.table"
done


v.in.mapgen -f in="$OUTFILE" out="${MAPNAME}_import"
v.category in="${MAPNAME}_import" out="$MAPNAME" option=add
g.remove vect="${MAPNAME}_import"

v.db.addtable "$MAPNAME" column="label varchar(25)"


## slow
while read LINE ; do
   CAT=`echo "$LINE" | awk -F'|' '{print $1}'`
   LABEL=`echo "$LINE" | awk -F'|' '{print $2}'`
   v.db.update map="$MAPNAME" column=label value="$LABEL" where="cat = $CAT"
done < "${OUTFILE}.table"

## or, faster
sed -e "s/^/INSERT INTO $MAPNAME (cat,label) values (/" \
    -e "s/|/,'/" \
    -e "s/$/');/" "${OUTFILE}.table" | db.execute

# another fast, but how to correctly quote ''? 
awk -F'|' -v MAPNAME=$MAPNAME \
  '{print "INSERT INTO " MAPNAME " (cat,label) values (" $1 ",\'" $2 "\');" }' \
  "${OUTFILE}.table" | db.execute

# all done



hopefully not too badly linewrapped by yahoo's helpfulness.

ok, still not very simple, but given free-form input data it is hard
to tell the computer what you want.


Hamish