NAME

v.profile - Vector map profiling tool

KEYWORDS

vector, profile, transect

SYNOPSIS

v.profile
v.profile --help
v.profile [-cz] input=name [type=string[,string,...]] [where=sql_query] [layer=string] [output=string] [separator=character] [dp=integer] buffer=float [map_output=name] [coordinates=east,north[,east,north,...]] [profile_map=name] [profile_where=sql_query] [profile_layer=integer] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-c: Do not print column names
-z: Do not print 3D vector data (z values)
Only affects 3D vectors
--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

input=name [required]: Name of input vector map
Or data source for direct OGR access
type=string[,string,...]: Input feature type
Options: point, line
Default: point,line
where=sql_query: WHERE conditions of SQL statement without ’where’ keyword
Example: income < 1000 and population >= 10000
layer=string: Layer number or name
Use features only from specified layer
Default: 1
output=string: Path to output text file or - for stdout
Default: -
separator=character: Field separator
Special characters: pipe, comma, space, tab, newline
Default: pipe
dp=integer: Number of significant digits
Options: 0-32
Default: 2
buffer=float [required]: Buffer (tolerance) for points in map units
How far points can be from sampling line
Default: 10
map_output=name: Name for profile line and buffer output map
Profile line and buffer around it will be written
coordinates=east,north[,east,north,...]: Coordinates for profiling line nodes
Specify profiling line vertexes and nodes
profile_map=name: Profiling line map
Vector map containing profiling line
profile_where=sql_query: WHERE conditions for input profile line map
Use to select only one line from profiling line map
profile_layer=integer: Profiling line map layer
Default: 1

DESCRIPTION

v.profile prints out distance and attributes of points/lines along a profiling line. Distance is calculated from the first profiling line coordinate pair or from the beginning of vector line.
The buffer (tolerance) parameter sets how far point can be located from a profiling line and still be included in the output data set.
The output map option can be used to visually check which points are profiled. The buffer (tolerance) setting does not affect lines. Lines are sampled at their crossing point with profiling line.

By default Z values are printed if input vector is a 3D map. It can be disabled with the -z flag.
The profiling line can be provided as N,E coordinate pairs or from an input vector map. As a profiling line must be a single line, the user should use the profile_where parameter to select a single line from a profile input map if it contains multiple vector features.

NOTES

Currently the module can profile only points and lines (including 3D ones). Areas and other complex features are not supported. If in future users can provide reasonable examples how area sampling should work and why it is important, area (or any other feature type) sampling can be added.

Due to bugs in GRASS native buffering algorithms, this module for now depends on GEOS and will not function if GRASS is compiled without GEOS. This restriction will be removed as soon as GRASS native buffer generation is fixed.

EXAMPLES

List all geonames along part of road NC-96 (NC Basic dataset). The output will be stored in a file for later usage. We will use comma as delimiter and three numbers after decimal separator for distance. Output file will contain data for all points, that are within 500 m range to profiling line.


v.profile input=geonames@PERMANENT output=/home/user/NC_96_geonames.csv\
  separator=comma dp=3 buffer=500 profile_map=roadsmajor@PERMANENT profile_where=cat=56
# Now lets see the output:
cat NC_96_geonames.csv
Number,Distance,cat,GEONAMEID,NAME,ASCIINAME,ALTERNATEN,FEATURECLA,FEATURECOD,COUNTRYCOD,CC2,ADMIN1,POPULATION,ELEVATION,GTOPO30,TIMEZONE,MODIFICATI,PPLKEY,SRC_ID,MAINT_ID
1,360.719,26881,4482019,"New Zebulon Elementary School","New Zebulon Elementary School","","S","SCH","US","","NC",0,106,91,"America/Iqaluit","2006-01-15 00:00:00",0,0,0
2,846.806,22026,4476596,"Little River, Township of","Little River, Township of","","A","ADMD","US","","NC",0,0,91,"America/Iqaluit","2006-01-15 00:00:00",0,0,0
3,2027.918,16681,4470608,"Hendricks Pond","Hendricks Pond","","H","RSV","US","","NC",0,0,91,"America/Iqaluit","2006-01-15 00:00:00",0,0,0
4,2027.918,16690,4470622,"Hendricks Dam","Hendricks Dam","","S","DAM","US","","NC",0,0,91,"America/Iqaluit","2006-01-15 00:00:00",0,0,0
5,2999.214,39338,4496159,"Union Chapel","Union Chapel","","","","US","","NC",0,0,96,"America/Iqaluit","2006-01-15 00:00:00",0,0,0
6,3784.992,43034,4500325,"Zebulon Airport","Zebulon Airport","","S","AIRP","US","","NC",0,108,98,"America/Iqaluit","2006-01-15 00:00:00",0,0,0

Create river valley crossection and provide river marker (Spearfish dataset):


# Take elevation samples
r.profile input=elevation.dem@PERMANENT output=/home/user/elevation.profile \
  profile=600570.27364,4920613.41838,600348.034348,4920840.38617
# Now get distance to place where river marker should be set
v.profile input=streams@PERMANENT output=/home/user/river_profile.csv \
  east_north=600570.27364,4920613.41838,600348.034348,4920840.38617

BUGS

Strings are enclosed in double quotes ", still quotes within string are not escaped.

Output does not contain Vector CAT values. Only way how to get CAT value is from the attribute table.

If sampled feature (point, line) contains multiple attribute entries (has multiple CAT values), only the first one is reported. If this is a limitation in some practical use case, a feature request in GRASS GIS issue tracker should be opened.

AUTHOR

Maris Nartiss

SOURCE CODE

Available at: v.profile source code (history)