Thanks Ian and Hamish,
I was eventually able to fix the problem by downloading a unprojected California layout shapefile (form <www.census.gov>) and then importing it via v.proj in the location with the digital elevation map. Apparently the official shapefile of California layout has a wrong latitude.
Next step is to connect the output table of the population model (population densities at weather stations) to the map I have just created. This would hopefully result in an interpolated raster.
Hamish suggested the following:
Load in site data with v.in.ascii & interpolate between sites with v.surf.rst.
According to the manual v.in.ascii uses the | separator. Is it worth to manually put the file in that format or do you think is better to convert it in a database to connect with a specific command?
Thank you,
Luigi
-------- Original Message --------
Subject: [GRASSLIST:9087] Re: GRASS 6 in a nutshell tutorial
Date: Wed, 16 Nov 2005 00:03:56 +0100
From: lponti@infinito.it
To: Ian MacMillan <ian_macmillan@umail.ucsb.edu>
CC: Hamish <hamish_nospam@yahoo.com>, GRASSLIST@baylor.edu
References: <43667143.6030900@infinito.it> <43689B17.9040302@itc.it> <436AA43E.2030709@infinito.it> <2a710737c668a9cf27237f3236b55a2f@umail.ucsb.edu> <43724994.2070505@infinito.it> <20051110181214.21c19d6a.hamish_nospam@yahoo.com> <43790A77.2050108@infinito.it> <29ded48ac16bbfc3492e5eff023d357a@umail.ucsb.edu>
Dear Ian,
the original metadata of my state outline shapefile is:
PROJCS["unnamed",GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY["EPSG",7019]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG",6269]],PRIMEM["Greenwich",0,AUTHORITY["EPSG",8901]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG",9108]],AXIS["Lat","NORTH"],AXIS["Long","EAST"],AUTHORITY["EPSG",4269]],PROJECTION["Albers"],PARAMETER["standard_parallel_1",34],PARAMETER["standard_parallel_2",40.5],PARAMETER["latitude_of_center",0],PARAMETER["Central_Meridian",-120],PARAMETER["False_Easting",0],PARAMETER["False_Northing",-4000000],UNIT["m",1]]
Based on this, following direction in the GRASS/cygwin installation page
http://geni.ath.cx/grass.html#toc15
I have created a dummy vector for reprojection of the raster DEM of western USA - e10g tile. Then I created a new location from EPSG code to match the vector .shp state outline file, and I have imported both the dummy raster DEM via "v.proj" and the vector state outline via "v.in.ogr".
Using "gdalinfo" on the original raster file (e10g), originated the following output:
gdalinfo c:/cygwin/home/andy/DEM_data/e10g
Driver: EHdr/ESRI .hdr Labelled
Size is 10800, 6000
Coordinate System is `'
Origin = (-180.000000,50.000000)
Pixel Size = (0.00833333,-0.00833333)
Corner Coordinates:
Upper Left (-180.0000000, 50.0000000)
Lower Left (-180.0000000, 0.0000000)
Upper Right ( -90.0000000, 50.0000000)
Lower Right ( -90.0000000, 0.0000000)
Center (-135.0000000, 25.0000000)
Band 1 Block=10800x1 Type=Int16, ColorInterp=Undefined
NoData Value=-500
Do you see anything wrong?
In addition, I tried to import v.in.e00 (after adding the required .exe file in the bin folder of GRASS) but I have not been successful yet.
Regards and thanks,
Luigi
On Mon, 14 Nov 2005 18:31:43 -0800
Ian MacMillan <ian_macmillan@umail.ucsb.edu> wrote:
Luigi, if you look at r.info and v.info, you will only find the projection information of your location, not necessarily the projection/datum/etc. information of the original data (I believe). Do you have the original metadata? If not, try running gdalinfo on your original data files to determine their original projection info.
man gdalinfo
will give you the correct syntax.G'luck
IanOn Nov 14, 2005, at 2:06 PM, Luigi Ponti wrote:
Thanks Amish,
looking at v.info and r.info, it seems the two maps have the same projection (see below). However, when looking at the output "d.where -w" for a sample map point (the San Francisco Bay), the longitude is very different in the two maps:
WGS84 Co-ordinates
EAST: NORTH: LON:
-191114.6346037 -24240.66895625 143:03:58.588289W 29:24:27.1
(San Francisco Bay on the California State vector layer - WRONG)1839139.30311877 663981.00484798 122:19:50.783112W 37:57:48.1
(San Francisco Bay on the Elevation Model raster layer - CORRECT)Do you think this could be due to an error in the import process or should I just look for another vector map?
Thanks again,
Luigi
v.info map=state layer=1
+---------------------------------------------------------------------- ------+
| Layer: state Organization:
|
| Mapset: luigi Source Date:
|
| Location: Cal_nad83-zone3 Name of creator: |
| Database: /home/andy
|
| Title:
|
| Map Scale: 1:1
|
| Map format: native
|
|---------------------------------------------------------------------- ------|
| Type of Map: Vector (level: 2)
|
|
|
| Number of points: 0 Number of areas: 51 |
| Number of lines: 0 Number of islands: 48 |
| Number of boundaries: 59 Number of faces: 0 |
| Number of centroids: 51 Number of kernels: 0 |
|
|
| Map is 3D: 0
|
| Number of dblinks: 1
|
|
|
| Projection: Lambert Conformal Conic (zone 0)
|
| N: 922206.900 S: -701781.905
|
| E: 1043412.917 W: -374425.808
|
| B: 0.000 T: 0.000
|
|
|
| Digitize threshold: 0.00000
|
| Comments:
|
|
|
+---------------------------------------------------------------------- ------+r.info map=e10g@PERMANENT
+---------------------------------------------------------------------- ------+
| Layer: e10g Date: Tue Nov 8 17:25:24 2005 |
| Mapset: PERMANENT Login of Creator: andy |
| Location: Cal_nad83-zone3
|
| DataBase: /home/andy
|
| Title: ( e10g )
|
|---------------------------------------------------------------------- ------|
|
|
| Type of Map: raster Number of Categories: 5443 |
| Data Type: CELL
|
| Rows: 7192
|
| Columns: 11628
|
| Total Cells: 83628576
|
| Projection: Lambert Conformal Conic (zone 0)
|
| N: 3353466 S: -3838238 Res: 999.95884316 |
| E: 6073284 W: -5555183 Res: 1000.04016168 |
| Range of data: min = -84 max = 5443
|
|
|
| Data Source:
|
|
|
|
|
|
|
| Data Description:
|
| generated by r.proj
|
|
|
|
|
+---------------------------------------------------------------------- ------+Hamish wrote:
I have imported both the vector and the raster with minimum trouble, since the first has a .prj file which GRASS recognized, and the second
had a detailed import tutorial in the cygwin-GRASS install page. However, despite the fact the the two layers supposedly have the same NAD83 projection info (I did not enter anything manually), when I try
to display them together on a GRASS monitor, the state layout is in
the middle of the ocean compared to the elevation raster.Is there a way to overlap the two layers or to chek for a coordinate
error?r.info and v.info will give you the map extents, you should then be able
to figure out which is correct.Also try "d.where -w" to give you a lat/lon value for different parts of your map which you can compare to the map on the wall.
Hamish
>
What happens if a big asteroid hits Earth? Judging from realistic simulations involving a sledge hammer and a common laboratory frog, we can assume it will be pretty bad.
- Dave Barry-------------------------------------------------------------
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