Hi Vishal,
I used ordinary google to take a lot of JPG images of nearly same scale.
Then I have put then together through GIMP. Georeferrencing helped me
make it a GRASS Raster data. The vectors followed by digitisation. A few labels here and there and THERE U have a GRASS Dataset.
Ur data.........
Pl give details.
1.What are the GRASS data sets (Raster + Vector ) U have (created).
2. Ur data shows from Amritsar to Agartala.. that is a Map of India itself,
if Bangalore is added.
3. GRASS uses DBF as default. Through open office U can manipulate this.
4. If U are learning, PGSql, why dont U 1st experiment with just DBF instead.
U can shift from DBF to PGSql after U master it.
5. v.in.ascii is easy to use on Ur GRASS data, from a cvs file, which U have attached
here.
If Ur problems are not answered, then, Iam sure U need help on PGSql it self.
Do clarify
Ravi Kumar
Vishal Mehta <vishalm1975 at gmail.com> wrote:
Hi Ravi,
Nice example. One question, did you use the image from Google Earth the free version or the paid version that allows incorporating own data?
I looked at your India example and got the sense that you might be able to provide some insights into my vector data challenges. I am more familiar with raster GRASS operations so far.. I have my data in a postgresql database (something i am also just learning)
So far I have 2 tables in my postgresql database. One is my masterfile, a table called 'stations ' that looks like this: WMoID, city, lat, long
420710,AMRITSAR, 31.63,74.86
421010,PATIALA,30.33,76.46
421310,HISSAR,29.16,75.73
421820,DELHI,28.58,77.20
and i prepared a table called 'data', which looks like this (i'm copying from openoffice thats why it looks a bit strange):
WMOID,N,10,0 CITY,C,50 YEAR,N,5,0 YDAY,N,4,0 TMAX,N,10,2 TMIN,N,10,2 TDAY,N,10,2 RAIN,N,10,2 VPD,N,10,2 SRAD,N,10,2 DAYLEN,N,10,0
427240 Agartala 1995 1 26 8.5 21.19 0 1112.83 341.2 37998
427240 Agartala 1995 2 24 7.39 19.43 0 1082.93 339.33 38019
427240 Agartala 1995 3 22.72 4.89 17.82 0 1097.42 360.24 38041
427240 Agartala 1995 4 24 4 18.5 0 1084.58 377.3 38065
427240 Agartala 1995 5 25.11 5.22 19.64 0 1155.05 374.59 38091
for each station.
What i want to do, and dont know how to (i looked at the GRASS online help which is just not enough for someone new to databases):
1. I want to use the 'stations' table to bring in as a vector map. Earlier, when i had the 'stations' as a csv file, i used v.in.ascii. i dont know what to use when its in a table in a pg database.
2. I also want to link the 'stations' to the 'data' table. i did this using v.db.connect and it seemed to work. But i dont know how its linking. When i had used v.in.ascii on a csv file, i had defined the WMOID as cat; and then in ' v.db.connect i had WMOID in the 'data' file be the key. But then it did'nt like it at all when i tried a SQL query- it seemed to not like having WMOID as the key, because it had duplicates. But how else can i link the 2 tables?
3. My final goal is to be able to write a script, where i can have every day's data from a particular column, become a vector map, then a raster using interpolation. To do this would i need my intial points vector file to be a 3d vector file?
any help would be great!
thanks,
vishal
On 3/23/06, RAVI KUMAR <ravivundavalli at yahoo.com> wrote: Hi,
an indian example is here.
http://freegis.gnu.org.in/grass_geosciencedataset.pdf
Ravi Kumar
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