[GRASS-user] Angle between segments of a polyline

GRASS GRASS user
1

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hi

a friend of mine wants (needs?) to determine the angle between segments
in an ESRI polyline (line vector feature). As there does not seem to be
an easy way in ArcGIS 9.2, I thought about askeng here:

Is there way of calculating these angles between the different line
segments in grass?

Thanks,

Rainer

- --
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation
Biology, UCT), Dipl. Phys. (Germany)

Centre of Excellence for Invasion Biology
Natural Sciences Building
Office Suite 2039
Stellenbosch University
Main Campus, Merriman Avenue
Stellenbosch
South Africa

Tel: +33 - (0)9 53 10 27 44
Cell: +27 - (0)8 39 47 90 42
Fax (SA): +27 - (0)8 65 16 27 82
Fax (D) : +49 - (0)3 21 21 25 22 44
Fax (FR): +33 - (0)9 58 10 27 44
email: Rainer@krugs.de

Skype: RMkrug
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.10 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/

iEYEARECAAYFAkxSf/AACgkQoYgNqgF2egoLxgCaAxTR0ZFA9HE4+4eR0WwaVO1A
+Z8An1BEl6K54bkiHdynkbjmExP1LFBa
=F9Yz
-----END PGP SIGNATURE-----

2

Rainer wrote:

a friend of mine wants (needs?) to determine the angle
between segments in an ESRI polyline (line vector feature).
As there does not seem to be an easy way in ArcGIS 9.2, I
thought about askeng here:

Is there way of calculating these angles between the
different line segments in grass?

first split the poly line up into individual segments with
  v.split vertices=1

then upload the slope of each line into the attribute table with
  v.to.db option=azimuth

finally compare the angle between each connecting segments.

Hamish

3

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hi Hamish,

thanks a lot - that sounds reasonably easy - might be another happy
GRASS (ex-ESRI) user?

Cheers,

Rainer

On 30/07/10 10:40, Hamish wrote:

Rainer wrote:

a friend of mine wants (needs?) to determine the angle
between segments in an ESRI polyline (line vector feature).
As there does not seem to be an easy way in ArcGIS 9.2, I
thought about askeng here:

Is there way of calculating these angles between the
different line segments in grass?

first split the poly line up into individual segments with
  v.split vertices=1

then upload the slope of each line into the attribute table with
  v.to.db option=azimuth

finally compare the angle between each connecting segments.

Hamish

- --
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation
Biology, UCT), Dipl. Phys. (Germany)

Centre of Excellence for Invasion Biology
Natural Sciences Building
Office Suite 2039
Stellenbosch University
Main Campus, Merriman Avenue
Stellenbosch
South Africa

Tel: +33 - (0)9 53 10 27 44
Cell: +27 - (0)8 39 47 90 42
Fax (SA): +27 - (0)8 65 16 27 82
Fax (D) : +49 - (0)3 21 21 25 22 44
Fax (FR): +33 - (0)9 58 10 27 44
email: Rainer@krugs.de

Skype: RMkrug
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.10 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/

iEYEARECAAYFAkxSkKYACgkQoYgNqgF2egoeCgCcCiC13P2N1qf5D9UyH76q9Au1
Wa0AmQGpZRL0U3yysGYeIW5Vt05zyddn
=kfpQ
-----END PGP SIGNATURE-----

4

Rainer M Krug pisze:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hi

a friend of mine wants (needs?) to determine the angle between segments
in an ESRI polyline (line vector feature). As there does not seem to be
an easy way in ArcGIS 9.2, I thought about askeng here:

Is there way of calculating these angles between the different line
segments in grass?

If problem concerns stream network, try to use r.stream.angle exension
J.