[GRASS-user] Problems using v.surf.idw

Fri Apr 16 01:59:39 PDT 2021

Hi all,

I have been trying to use v.surf.idw the past few days without success.

The image attached is a screen capture from the Map Display. There is a category
raster (green regions) with a gap (lake Chad) that must be filled with the
nearest neighbour category. The strategy is to create a points vector from the raster
and then apply v.surf.idw with npoints=1.

If the density of points is too high (> 10 000) the module fails with the
message "Killed". With fewer points the module fails with the message
"ERROR: No points found". Below is a log with an example. I have
tried many different combinations of resolution and number of points, I also tried different mapsets, SQLite and Postgres back-ends, but the result is always the same.

What can be going wrong?

P.S.: there is previous thread with similar symptoms, but seems to have been a different issue: http://osgeo-org.1560.x6.nabble.com/v-surf-idw-Not-Working-td5457170.html

Thank you.

Luís

GRASS 7.8.2 (S4AHomolosine):~ > g.region nsres=20000 ewres=20000 w=1474000 n=1626000 e=1760000 s=1383000
GRASS 7.8.2 (S4AHomolosine):~ > r.to.vect type=point input=soil_map_rcl_no_water output=soil_map_rcl_no_water --overwrite
WARNING: Vector map <soil_map_rcl_no_water> already exists and will be
overwritten
Extracting points...
100%
Building topology for vector map <soil_map_rcl_no_water at MAL>...
Registering primitives...
r.to.vect complete.
GRASS 7.8.2 (S4AHomolosine):~ > v.info soil_map_rcl_no_water
+----------------------------------------------------------------------------+
| Name: soil_map_rcl_no_water |
| Mapset: MAL |
| Location: S4AHomolosine |
| Database: /home/duque004/Work/GRASSDATA |
| Title: |
| Map scale: 1:1 |
| Name of creator: duque004 |
| Organization: |
| Source date: Fri Apr 16 10:10:31 2021 |
| Timestamp (first layer): none |
|----------------------------------------------------------------------------|
| Map format: native |
|----------------------------------------------------------------------------|
| Type of map: vector (level: 2) |
| |
| Number of points: 114 Number of centroids: 0 |
| Number of lines: 0 Number of boundaries: 0 |
| Number of areas: 0 Number of islands: 0 |
| |
| Map is 3D: No |
| Number of dblinks: 1 |
| |
| Projection: unknown |
| |
| N: 1615875 S: 1393125 |
| E: 1749785.71428571 W: 1484214.28571429 |
| |
| Digitization threshold: 0 |
| Comment: |
| |
+----------------------------------------------------------------------------+

GRASS 7.8.2 (S4AHomolosine):~ > g.region nsres=100 ewres=100 w=1474000 n=1626000 e=1760000 s=1383000
GRASS 7.8.2 (S4AHomolosine):~ > v.surf.idw npoints=1 input=soil_map_rcl_no_water output=soil_map_rcl_water_fill --overwrite
Input vector map <soil_map_rcl_no_water at MAL> is 2D - using categories to
interpolate
WARNING: No record for point (cat = 1)
WARNING: No record for point (cat = 2)
WARNING: No record for point (cat = 3)
WARNING: No record for point (cat = 4)
WARNING: No record for point (cat = 5)
WARNING: No record for point (cat = 6)
WARNING: No record for point (cat = 7)
WARNING: No record for point (cat = 8)
WARNING: No record for point (cat = 9)
WARNING: No record for point (cat = 10)
WARNING: No record for point (cat = 11)
WARNING: No record for point (cat = 12)
WARNING: No record for point (cat = 13)
WARNING: No record for point (cat = 14)
WARNING: No record for point (cat = 15)
WARNING: No record for point (cat = 16)
WARNING: No record for point (cat = 17)
WARNING: No record for point (cat = 18)
WARNING: No record for point (cat = 19)
WARNING: No record for point (cat = 20)
WARNING: No record for point (cat = 21)
WARNING: No record for point (cat = 22)
WARNING: No record for point (cat = 23)
WARNING: No record for point (cat = 24)
WARNING: No record for point (cat = 25)
WARNING: No record for point (cat = 26)
WARNING: No record for point (cat = 27)
WARNING: No record for point (cat = 28)
WARNING: No record for point (cat = 29)
WARNING: No record for point (cat = 30)
WARNING: No record for point (cat = 31)
WARNING: No record for point (cat = 32)
WARNING: No record for point (cat = 33)
WARNING: No record for point (cat = 34)
WARNING: No record for point (cat = 35)
WARNING: No record for point (cat = 36)
WARNING: No record for point (cat = 37)
WARNING: No record for point (cat = 38)
WARNING: No record for point (cat = 39)
WARNING: No record for point (cat = 40)
WARNING: No record for point (cat = 41)
WARNING: No record for point (cat = 42)
WARNING: No record for point (cat = 43)
WARNING: No record for point (cat = 44)
WARNING: No record for point (cat = 45)
WARNING: No record for point (cat = 46)
WARNING: No record for point (cat = 47)
WARNING: No record for point (cat = 48)
WARNING: No record for point (cat = 49)
WARNING: No record for point (cat = 50)
WARNING: No record for point (cat = 51)
WARNING: No record for point (cat = 52)
WARNING: No record for point (cat = 53)
WARNING: No record for point (cat = 54)
WARNING: No record for point (cat = 55)
WARNING: No record for point (cat = 56)
WARNING: No record for point (cat = 57)
WARNING: No record for point (cat = 58)
WARNING: No record for point (cat = 59)
WARNING: No record for point (cat = 60)
WARNING: No record for point (cat = 61)
WARNING: No record for point (cat = 62)
WARNING: No record for point (cat = 63)
WARNING: No record for point (cat = 64)
WARNING: No record for point (cat = 65)
WARNING: No record for point (cat = 66)
WARNING: No record for point (cat = 67)
WARNING: No record for point (cat = 68)
WARNING: No record for point (cat = 69)
WARNING: No record for point (cat = 70)
WARNING: No record for point (cat = 71)
WARNING: No record for point (cat = 72)
WARNING: No record for point (cat = 73)
WARNING: No record for point (cat = 74)
WARNING: No record for point (cat = 75)
WARNING: No record for point (cat = 76)
WARNING: No record for point (cat = 77)
WARNING: No record for point (cat = 78)
WARNING: No record for point (cat = 79)
WARNING: No record for point (cat = 80)
WARNING: No record for point (cat = 81)
WARNING: No record for point (cat = 82)
WARNING: No record for point (cat = 83)
WARNING: No record for point (cat = 84)
WARNING: No record for point (cat = 85)
WARNING: No record for point (cat = 86)
WARNING: No record for point (cat = 87)
WARNING: No record for point (cat = 88)
WARNING: No record for point (cat = 89)
WARNING: No record for point (cat = 90)
WARNING: No record for point (cat = 91)
WARNING: No record for point (cat = 92)
WARNING: No record for point (cat = 93)
WARNING: No record for point (cat = 94)
WARNING: No record for point (cat = 95)
WARNING: No record for point (cat = 96)
WARNING: No record for point (cat = 97)
WARNING: No record for point (cat = 98)
WARNING: No record for point (cat = 99)
WARNING: No record for point (cat = 100)
WARNING: No record for point (cat = 101)
WARNING: No record for point (cat = 102)
WARNING: No record for point (cat = 103)
WARNING: No record for point (cat = 104)
WARNING: No record for point (cat = 105)
WARNING: No record for point (cat = 106)
WARNING: No record for point (cat = 107)
WARNING: No record for point (cat = 108)
WARNING: No record for point (cat = 109)
WARNING: No record for point (cat = 110)
WARNING: No record for point (cat = 111)
WARNING: No record for point (cat = 112)
WARNING: No record for point (cat = 113)
WARNING: No record for point (cat = 114)
0 points loaded
ERROR: No points found

--
Luís

Sent with [ProtonMail](https://protonmail.com) Secure Email.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/grass-user/attachments/20210416/89c16e00/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: LakeChadFilling.png
Type: image/png
Size: 29760 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/grass-user/attachments/20210416/89c16e00/attachment-0001.png>