[GRASSLIST:9087] Re: GRASS 6 in a nutshell tutorial
lponti at infinito.it
lponti at infinito.it
Tue Nov 15 18:03:56 EST 2005
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 at 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
> Ian
>
> On 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 at 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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