[GRASS-user] v.to.rast densify option gives null output

GRASS GRASS user
1

Hi,

When I use the -d flag in v.to.rast, cells output are null. Omitting the -d
flag works fine for rasterization with default thin lines.

Not sure how to resolve. Is there an alternative GRASS module that can do
the same?

Cheers,
Richard
GRASS GIS 7.0 svn / rev 57721 / python 2.7.3
Mint Linux / Ubuntu Precise

Example of output:
v.to.rast -d --overwrite input=waterways_finaledit@PERMANENT type=area
output=waterways_finaledit_vtr_dense use=val value=5
Pass 1 of 3:
Reading areas...
Reading features...
Writing raster map...
Pass 2 of 3:
Reading areas...
Writing raster map...
Pass 3 of 3:
Reading areas...
Writing raster map...
Converted areas: 8415 of 13694
v.to.rast complete.

Type of Map: raster Number of Categories: 0 |
| Data Type: CELL
|
| Rows: 11319
|
| Columns: 7737
|
| Total Cells: 87575103
|
| Projection: UTM (zone 47)
|
| N: 2379330 S: 1360620 Res: 90
|
| E: 971010 W: 274680 Res: 90
|
| Range of data: min = NULL max = NULL
|
|
|
| Data Source:
|
| Vector Map: waterways_finaledit@PERMANENT
|
| Original scale from vector map: 1:1
|
|
|
| Data Description:
|
| generated by v.to.rast

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2

On Fri, Feb 21, 2014 at 10:49 AM, RichardCooper <richtcooper@hotmail.com> wrote:

Hi,

When I use the -d flag in v.to.rast, cells output are null. Omitting the -d
flag works fine for rasterization with default thin lines.

The -d option of v.to.rast works only for lines, not for boundaries.
You would need to convert the boundaries to lines and then use
v.to.rast type=line -d.

Markus M

Not sure how to resolve. Is there an alternative GRASS module that can do
the same?

Cheers,
Richard
GRASS GIS 7.0 svn / rev 57721 / python 2.7.3
Mint Linux / Ubuntu Precise

Example of output:
v.to.rast -d --overwrite input=waterways_finaledit@PERMANENT type=area
output=waterways_finaledit_vtr_dense use=val value=5
Pass 1 of 3:
Reading areas...
Reading features...
Writing raster map...
Pass 2 of 3:
Reading areas...
Writing raster map...
Pass 3 of 3:
Reading areas...
Writing raster map...
Converted areas: 8415 of 13694
v.to.rast complete.

Type of Map: raster Number of Categories: 0 |
| Data Type: CELL
|
| Rows: 11319
|
| Columns: 7737
|
| Total Cells: 87575103
|
| Projection: UTM (zone 47)
|
| N: 2379330 S: 1360620 Res: 90
|
| E: 971010 W: 274680 Res: 90
|
| Range of data: min = NULL max = NULL
|
|
|
| Data Source:
|
| Vector Map: waterways_finaledit@PERMANENT
|
| Original scale from vector map: 1:1
|
|
|
| Data Description:
|
| generated by v.to.rast

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3

Thanks. I converted to lines, added categories and rasterized:

v.type input=waterways_finaledit@PERMANENT output=waterways_finaledit_lines
from_type=boundary to_type=line

v.category input=waterways_finaledit_lines@PERMANENT type=line
output=waterways_finaledit_lines_catadd option=add

v.to.rast -d --overwrite --verbose
input=waterways_finaledit_lines_catadd@PERMANENT type=line
output=waterways_finaledit_lines_catadd_vtr_dense use=val value=5

Richard

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