[R-sig-Geo] From spatial points to "spatial pictures"
Maurizio Marchi
mauriziomarchi85 at gmail.com
Wed Aug 5 15:56:23 CEST 2015
Hi everybody,
I'm maurizio Marchi and I'm working as a post-doc at the Forestry Research
Centre of Arezzo (Italy) and I have a question concerning spatial points
management.
During my research activities I have to collect data about the crown
projection on the ground of trees. The aim is to "measure" the crown area
and to draw a sort of picture on GIS software (QGIS in my case) to analyze
the area and the perimeter of the crowns compared to the "free area" of a
plot (generally a circular plot) to have an idea of how much photosynthetic
radiation is able to reach the soil. My working steps are:
1) During the survey on the field each crown of each tree is initially
"drawn" collecting 8 points that have to be connected to become a spatial
polygon:
###---example of table to be processed
TREE POINT X Y
1 1 x y
1 2 x y
1 3 x y
1 4 x y
1 5 x y
1 6 x y
1 7 x y
1 8 x y
2 1 x y
2 2 x y
2 3 x y
2 4 x y
2 5 x y
2 6 x y
2 7 x y
2 8 x y
[......................................]
N 8 x y
2) the points,sorted by Tree become the vertices of the polygons
3) The polygons have to be processed to obtain a smoothed polygons,
circumscribing the polygonal crowns (e.g.
http://grasswiki.osgeo.org/wiki/V.generalize_tutorial)
I generally do it on QGIS and GRASS but is there something more appropriate
on R to do this? for example with rgdal or sp package?
Many thanks
--
Maurizio Marchi
Calenzano (FI) - Italy
ID Skype: maurizioxyz
Ubuntu 14.04 LTS
linux user 552742
[[alternative HTML version deleted]]
More information about the R-sig-Geo
mailing list