[GRASS-user] 0 points loaded in v.surf.idw

GRASS GRASS user
1

Hi,

I’m trying to import some points from Postgres and convert it into raster using v.in.ogr and v.surf.idw

v.in.ogr dsn=“PG:host=tsf.noblis.org dbname=gis port=5433” layer=regcm.huss_monavg_2038 output=huss_monavg_2038_395_875 where=‘timestamp=395.875’

v.surf.idw input=huss_monavg_2038_395_875 column=huss output=rast_huss_monavg_2038_huss395_875

When I run the v.surf.idw, I get

13936 records selected from table

0 points loaded

ERROR: No data points found

When I try to view it in the map display, I see nothing yet I do see 13936 points which is the right number of points when I do v.info.

v.info huss_monavg_2038_395_875

Layer: huss_monavg_2038_395_875 |

| Mapset: PERMANENT |

| Location: RegCM-4269 |

| Database: /data/grassdata/echang |

| Title: |

| Map scale: 1:1 |

| Map format: native |

| Name of creator: echang |

| Organization: |

| Source date: Tue Jul 13 15:44:59 2010 |

|----------------------------------------------------------------------------|

| Type of Map: vector (level: 2) |

| |

| Number of points: 13936 Number of areas: 0 |

| Number of lines: 0 Number of islands: 0 |

| Number of boundaries: 0 Number of faces: 0 |

| Number of centroids: 0 Number of kernels: 0 |

| |

| Map is 3D: No |

| Number of dblinks: 1 |

| |

| Projection: Lat/Lon |

| N: 70:15:29.96521N S: 19:27:00.387268N |

| E: 35:43:20.669862W W: 157:42:49.097902W |

| |

| Digitization threshold: 0 |

| Comments: |

|

It is a large file so I tried making the region quite small

zone: 0

datum: nad83

ellipsoid: grs80

north: 70:15:29.96521N

south: 69N

west: 120W

east: 110W

nsres: 0:15:05.993042

ewres: 0:20

rows: 5

cols: 30

cells: 150

Is there a problem with the resolution? Any ideas?

Thanks,

Elizabeth

Elizabeth Chang

Lead

Noblis

3150 Fairview Park Drive Sourth

Falls Church, VA 22042

703-610-2321 (office)

elizabeth.chang@noblis.org

Noblis

For the best of reasons

2

On Tue, Jul 13, 2010 at 10:27 PM, Chang, Elizabeth
<Elizabeth.Chang@noblis.org> wrote:

Hi,

I’m trying to import some points from Postgres and convert it into raster
using v.in.ogr and v.surf.idw

v.in.ogr dsn="PG:host=tsf.noblis.org dbname=gis port=5433"
layer=regcm.huss_monavg_2038 output=huss_monavg_2038_395_875
where='timestamp=395.875'

Please post a snippet of the output or check it yourself of

v.db.select huss_monavg_2038_395_875

just to be sure that you got the data actually in which you want to be in.

Furthermore,

.... map extent:
| N: 70:15:29.96521N S: 19:27:00.387268N |
| E: 35:43:20.669862W W: 157:42:49.097902W |

... computational (current) region extent;
north: 70:15:29.96521N
south: 69N
west: 120W
east: 110W
nsres: 0:15:05.993042
ewres: 0:20

The "south" value of the computational region does not quite cover
the map (intentionally?). Likeweise east and west. (also the pixels
are non-square).

Perhaps you want to first use (set resolution as appropriate):
g.region vect=huss_monavg_2038_395_875 res=0:20 -a

to better fit the computational region to the map, then run v.surf.idw.

hope this helps,
Markus