Problems with v.net.path

GRASS GRASS user
1

Hello,

I’m trying to extract a segment of the coastline between two user-defined points, following this workflow:

  1. Use v.split to increase the number of vertices along the coastline (improve precision).
  2. Provide approximate start and end point locations in a file.
  3. Snap these points to the nearest locations on the split coastline.
  4. Generate a network from the snapped points and the split coastline using v.net.
  5. Extract the segment between the points using v.net.path.

Here are the commands I’m using:

# === 0. Input and output directories ===
rootsdir="/home/amaru/Documents/" 
cartodir=$rootsdir"CARTOGRAFIA/COSTA_RICA/"
basedirs=$rootsdir"LABFITMAR/ADVISORIES/"
figsdirs=$basedirs"FIGURES/"
grassdir="/home/amaru/grassdata/"

ipoints=$basedirs"/USER_POINTS/cmver_test-2025.csv" 

grass "$grassdir/CRTM05/PERMANENT" --text <<EOF
    v.in.ascii input=$ipoints \
        output=segment_points separator=comma cat=1 x=3 y=4 \
	col="cat integer, segment integer, east double precision, \
            north double precision,label varchar(6)" --overwrite

    v.clean input=cr_lims_lines output=cr_lims_lines_cleaned tool=snap threshold=500 --overwrite

    v.split input=cr_lims_lines_cleaned output=cr_lims_lines_splt \
        length=1 units=kilometers --overwrite

    v.distance from=segment_points to=cr_lims_lines_splt \
        upload=dist,to_x,to_y table=dist_new to_type=line \
        output=segment_points_snapped --overwrite

    v.db.select map=segment_points_snapped col=cat,to_x,to_y > $basedirs"nn_points.txt"
    v.in.ascii input=$basedirs"nn_points.txt" separator=pipe \
        output=snapped_points cat=1 x=2 y=3 skip=1 \
        columns="cat integer,east double precision, north double precision" --overwrite
 	
    v.net cr_lims_lines points=snapped_points op=connect threshold=10000 \
        arc_layer=1 node_layer=2 output=cr_coast_net1 --overwrite

    echo "1 0 1" | v.net.path cr_coast_net1 arc_layer=1 arc_type=line node_layer=2 \
        out=test_segment --overwrite
EOF

All works fine until de use of v.net. However v.net.path does not generate the segment and I got a warning:

WARNING: The point with category [1] is not reachable from the point
with category [0]
WARNING: Destination(s) 1 unreachable (including points outside the
threshold)

I’d appreciate any help or insight on what might be going wrong. I’ve shared the relevant files in case anyone can take a look: It is the coastline and the file with the start and end points of the segment.

Thank you all