[GRASS-dev] NVIZ problem with 3D polygons

[del cadarn]

Dear Mr. Neteler,

thank you for your input (and for your book about Grass, without which I don't know how I would approach Grass... actually I'm borrowing my employer's copy so if you have any free ones floating around... ;) ). 

Your solution worked for the v.extrude buildings... brilliant.
However it doesn't work for the imported DXF, here is a description of the details
 |   Number of points:       0               Number of areas:      0          |
 |   Number of lines:        0               Number of islands:    0          |
 |   Number of boundaries:   0               Number of faces:      53516      |
 |   Number of centroids:    0               Number of kernels:    0          |
 |                                                                            |
 |   Map is 3D:              Yes                                              |
 |   Number of dblinks:      1    

Do I need to apply v.type on another categorie?

               Thank you,

                          DelphineJB

From: neteler at osgeo.org
Date: Tue, 16 Aug 2011 11:57:20 +0200
Subject: Re: [GRASS-dev] NVIZ problem with 3D polygons
To: del_cadarn at hotmail.com
CC: grass-dev at lists.osgeo.org

On Thu, Aug 11, 2011 at 11:30 AM, del cadarn <del_cadarn at hotmail.com> wrote:







Bonjour,


I've also posted this on the GRASS-users mailist but since I didn't receive an answer, I thought I might try this one.

Sorry, I overlooked it.
 

I am having problems to see vectors I have added height to with 
v.extrude . The trick is that I am actually using the e.g. given in 
NETELER, M and H. MITASOVA Open Source GIS a GRASS GIS Approach with the North Carolina sample data. So in theory, this example should really be working...


Thanks :) But there was an error in that part of the book:

http://www.grassbook.org/errata_menu3rd.php

 

Here is what I did 


g.region rast=el_D792_6m -p


v.extract P079215 out=bldg_resid_a where="layer='BLDG_RESID_BL'"

v.extract P079215 out=bldg_cmcl_a where="layer='BLDG_COMMER_BL'"


Here the step to change the vector type was omitted in the book example.

v.info bldg_resid_a -t
nodes=14
points=0
lines=11
boundaries=0


centroids=0
areas=0
islands=0
faces=0
kernels=0
primitives=11
map3d=1

--> no boundaries but lines only.

So you need to perform here:

 v.type bldg_resid_a out=bldg_resid_bnd type=line,boundary


 v.centroids bldg_resid_bnd out=bldg_resid_pol
 v.type bldg_cmcl_a out=bldg_cmcl_bnd type=line,boundary
 v.centroids bldg_cmcl_bnd out=bldg_cmcl_pol

 # add height of the building (use new input maps)
 v.extrude -t bldg_resid_pol out=bldg_resid_a_3d height=10 \


                 elev=el_D792_6m
 v.extrude -t bldg_cmcl_pol  out=bldg_cmcl_a_3d height=15 \
                 elev=el_D792_6m

# verify
v.info -t bldg_resid_a_3d | grep faces


faces=36

v.info -t bldg_cmcl_a_3d | grep faces
faces=55


g.region rural_1m -p

nviz elev_lid792_1m col=ortho_2001_t792_1m vect=bldg_resid_a_3d,bldg_cmcl_a_3dI've encountered also this problem when I tried to visualised a DXF file in NVIZ. The windmill shows up but in broken lines which is no good to me.



... now you see the buildings nicely.

> Thank you for your help, I'm very new to GIS and Open Source, 
and I must admit I don't know where to find the ressources to help...


It will be the same problem with solution to be applied from above.

Hope this helps,
Markus

-- 
http://www.grassbook.org/neteler/



 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/grass-dev/attachments/20110825/47168c71/attachment-0001.html