[GRASS-user] Using r.mapcalc to extract road network from satellite imagery

2010-04-07 Thread Nathaniel Iwuchukwu 
Hi all,
i have been using V.clean to get a straight line of road network from my
satellite imagery which i have successfully classified and converted to
vector from raster.
I read some articles on r.mapcalc as a possiblility for extracting a clean
road network but i tried using it but did not notice any visible change on
the map. though am not good with using all the variable available for it.
have anyone used this command or is there a better command i could use?
Thanks.
Nath
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[GRASS-user] road extraction using grass

2010-04-04 Thread Nathaniel Iwuchukwu 
So far, i have been able to extra road from a satellite imagery but it has
broken lines and it also captured buildings. these are the steps i followed
to arrive at this stage:
GRASS 6.4.0RC5 (Pittsburgh):~/Desktop  g.mlist rast
pitt_composite
pitts.blue
pitts.green
pitts.red
pittthin
GRASS 6.4.0RC5 (Pittsburgh):~/Desktop  g.region rast=pitts.red
GRASS 6.4.0RC5 (Pittsburgh):~/Desktop  d.mon x0
using default visual which is TrueColor
ncolors: 16777216
Graphics driver [x0] started
GRASS 6.4.0RC5 (Pittsburgh):~/Desktop  d.rgb red=pitts.red
green=pitts.green blue=pitts.blue
 100%
GRASS 6.4.0RC5 (Pittsburgh):~/Desktop  d.where

Buttons:
Left:   where am i
Middle: draw to/from here
Right:  quit this

 EAST: NORTH:
569059.3754464771.875
569059.3754464778.125
5694254464771.875
569409.3754464521.875
569050 4464531.25
  569062.54464778.125
GRASS 6.4.0RC5 (Pittsburgh):~/Desktop  g.region -p w=569062 e=569425
s=4464778 n=4464771
ERROR: Invalid region: North must be larger than South
GRASS 6.4.0RC5 (Pittsburgh):~/Desktop  g.region -p w=569062 e=569425
s=4464771 n=4464778
projection: 1 (UTM)
zone:   17
datum:  nad83
ellipsoid:  grs80
north:  4464778
south:  4464771
west:   569062
east:   569425
nsres:  0.30434783
ewres:  0.3
rows:   23
cols:   1210
cells:  27830
GRASS 6.4.0RC5 (Pittsburgh):~/Desktop  r.composite red=pitts.red
green=pitts.green blue=pitts.blue out=pitts
Creating color table for output raster map...
 100%
Writing raster map pitts...
 100%
r.composite complete. Raster map pitts created.
GRASS 6.4.0RC5 (Pittsburgh):~/Desktop  d.rast pitts
 100%
GRASS 6.4.0RC5 (Pittsburgh):~/Desktop  d.rgb red=pitts.red
green=pitts.green blue=pitts.blue
 100%
GRASS 6.4.0RC5 (sis):~/Desktop  d.rast pitts
 100%
GRASS 6.4.0RC5 (sis):~/Desktop  v.digit -n train bgcmd=d.rast pitts
 100%
Building topology for vector map train...
Registering primitives...
5 primitives registered
21 vertices registered
Building areas...
 100%
0 areas built
0 isles built
Attaching islands...
Attaching centroids...
 100%
Number of nodes: 9
Number of primitives: 5
Number of points: 0
Number of lines: 0
Number of boundaries: 4
Number of centroids: 1
Number of areas: 0
Number of isles: 0
Number of incorrect boundaries: 4
Number of centroids outside area: 1
Region restored to original extent.
GRASS 6.4.0RC5 (sis):~/Desktop  v.to.rast in=traingis out=traingis use=attr
type=area col=label_id labelcolumn=label
Loading data...
Reading features...
 100%
Writing raster map...
 100%
Converted areas: 0 of 0
Converted points/lines: 0 of 0
v.to.rast complete.
GRASS 6.4.0RC5 (sis):~/Desktop  i.group group=sislabgp subgroup=sislabsub
in=sismap.red,sismap.green,sismap.blue
Adding raster map sismap@permanent to group
Adding raster map sismap.gr...@permanent to group
Adding raster map sismap.b...@permanent to group
Adding raster map sismap@permanent to subgroup
Adding raster map sismap.gr...@permanent to subgroup
Adding raster map sismap.b...@permanent to subgroup
i.group complete.
GRASS 6.4.0RC5 (sis):~/Desktop  i.gensigset trainingmap=trainsis
group=sislabgp subgroup=sislabsub signaturefile=sist.sig
Finding training classes...
 100%
3 classes found
Reading raster maps...
 100%
Clustering class 1 (3903 pixels)...
Number of subclasses is 4
Clustering class 2 (3126 pixels)...
Number of subclasses is 5
Clustering class 3 (2593 pixels)...
Number of subclasses is 4
i.gensigset complete.
GRASS 6.4.0RC5 (sis):~/Desktop  i.smap group=sislabgp subgroup=sislabsub
signaturefile=sist.sig out=test_class
Processing rows 1-128 (of 1833)...
Processing rows 129-256 (of 1833)...
Processing rows 257-384 (of 1833)...
Processing rows 385-512 (of 1833)...
Processing rows 513-640 (of 1833)...
Processing rows 641-768 (of 1833)...
Processing rows 769-896 (of 1833)...
Processing rows 897-1024 (of 1833)...
Processing rows 1025-1152 (of 1833)...
Processing rows 1153-1280 (of 1833)...
Processing rows 1281-1408 (of 1833)...
Processing rows 1409-1536 (of 1833)...
Processing rows 1537-1664 (of 1833)...
Processing rows 1665-1792 (of 1833)...
Processing rows 1793-1833 (of 1833)...
Writing raster map test_class...
 100%
i.smap complete.
GRASS 6.4.0RC5 (sis):~/Desktop  d.rast test_class
 100%
GRASS 6.4.0RC5 (sis):~/Desktop  r.null test_class setnull=18
 100%
GRASS 6.4.0RC5 (sis):~/Desktop  d.rast test_class
 100%
GRASS 6.4.0RC5 (sis):~/Desktop  r.thin
GRASS 6.4.0RC5 (sis):~/Desktop  d.rast test_test
WARNING: Socket is already in use or not accepting connections.
WARNING: Use d.mon to select a monitor
ERROR: No graphics device selected
GRASS 6.4.0RC5 (sis):~/Desktop  d.mon x0
using default visual which is TrueColor
ncolors: 16777216
Graphics driver [x0] started
GRASS 6.4.0RC5 (sis):~/Desktop  d.rast test_test
 100%
GRASS 6.4.0RC5 (sis):~/Desktop  r.to.vect test_test feature=line
out=roadsExtracting lines...
 100%
 100%
Building

[GRASS-user] Re: grass-user Digest, Vol 47, Issue 52

2010-03-31 Thread Nathaniel Iwuchukwu 
Hi all


 i am getting an error when i run the i.gensigset on the training map i
 created and the trainig map is blank after i perform vector to raster.
 this is what i typed and the result:
 GRASS 6.4.0RC5 (sis):~/Desktop  i.gensigset trainingmap=traingis
 group=sislabgp subgroup=sislabsub signaturefile=sislab.sig
 Finding training classes...
  100%
 ERROR: Training map has no classes
 does snyone have any clue why i don't have classes in my training map?



 what should i do. thanks

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[GRASS-user] Training map error. missing classes

2010-03-31 Thread Nathaniel Iwuchukwu 
 Hi all


 i am getting an error when i run the i.gensigset on the training map i
 created and the trainig map is blank after i perform vector to raster.
  this is what i typed and the result:
 GRASS 6.4.0RC5 (sis):~/Desktop  i.gensigset trainingmap=traingis
 group=sislabgp subgroup=sislabsub signaturefile=sislab.sig
 Finding training classes...
  100%
 ERROR: Training map has no classes
 does snyone have any clue why i don't have classes in my training map?



 what should i do. thanks


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[GRASS-user] Extracting road network from satellite image using GRASS

2010-03-29 Thread Nathaniel Iwuchukwu 
Please what's the procedure or commands for extrating road network from a
raster map? i think i have been going round the circle with classofocation
and rectification of image. i have used this commands but i don't get any
results:
i.group
i.composite
i.class
i.cluster
r.digit
i.maxlik
i.gensigset
nothing seems to get me the road network result i want.
Please i need help and i am running GRASS on Linux Ubuntu.
thanks.
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