[GRASS-user] Importing .tif

[Markus Metz]

On Mon, Jul 16, 2018 at 6:50 PM, Rich Shepard <rshepard at appl-ecosys.com>
wrote:
>
> On Mon, 16 Jul 2018, Markus Metz wrote:
>
>> If you use the -o flag, you are potentially corrupting the data. The
>> safest is to create a new location directly from the data to be imported,
>> unless there is a good reason to assume that the srs info in the data as
>> reported by gdalinfo is wrong.
>
>
> Markus,
>
>   I understand this. However, when I use the proj.4 string returned by
> 'gdalinfo -proj4' I am shown two different projections. I want to learn
how
> to do this correctly.

The proj4 string can not contain all the information present in WKT. As I
mentioned before, the safest is to create a new location directly from the
data to be imported, unless there is a good reason to assume that the srs
info in the data as reported by gdalinfo is wrong.

Markus M

> Here's an example:
>
> $ gdalinfo 45122c3307.tif -proj4 -nomd
> Driver: GTiff/GeoTIFF
> Files: 45122c3307.tif
>        45122c3307.aux
> Size is 2215, 3088
> Coordinate System is:
> PROJCS["NAD83(HARN) / Oregon North",
>     GEOGCS["NAD83(HARN)",
>         DATUM["NAD83_High_Accuracy_Reference_Network",
>             SPHEROID["GRS 1980",6378137,298.257222101,
>                 AUTHORITY["EPSG","7019"]],
>             TOWGS84[0,0,0,0,0,0,0],
>             AUTHORITY["EPSG","6152"]],
>         PRIMEM["Greenwich",0,
>             AUTHORITY["EPSG","8901"]],
>         UNIT["degree",0.0174532925199433,
>             AUTHORITY["EPSG","9122"]],
>         AUTHORITY["EPSG","4152"]],
>     PROJECTION["Lambert_Conformal_Conic_2SP"],
>     PARAMETER["standard_parallel_1",46],
>     PARAMETER["standard_parallel_2",44.33333333333334],
>     PARAMETER["latitude_of_origin",43.66666666666666],
>     PARAMETER["central_meridian",-120.5],
>     PARAMETER["false_easting",8202099.737532808],
>     PARAMETER["false_northing",0],
>     UNIT["international_feet",0.3048],
>     AXIS["X",EAST],
>     AXIS["Y",NORTH]]
> PROJ.4 string is:
> '+proj=lcc +lat_1=46 +lat_2=44.33333333333334 +lat_0=43.66666666666666
+lon_0=-120.5 +x_0=2500000 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0
+units=ft +no_defs '
> Origin = (7722808.500000000000000,600993.000000000000000)
> Pixel Size = (1.500000000000000,-1.500000000000000)
> Corner Coordinates:
> Upper Left  ( 7722808.500,  600993.000) (122d21'46.47"W, 45d17'59.99"N)
> Lower Left  ( 7722808.500,  596361.000) (122d21'44.98"W, 45d17'14.27"N)
> Upper Right ( 7726131.000,  600993.000) (122d21' 0.00"W, 45d18' 0.75"N)
> Lower Right ( 7726131.000,  596361.000) (122d20'58.51"W, 45d17'15.02"N)
> Center      ( 7724469.750,  598677.000) (122d21'22.49"W, 45d17'37.51"N)
> Band 1 Block=2215x1 Type=Byte, ColorInterp=Red
>   Description = Band_1
>
> Band 2 Block=2215x1 Type=Byte, ColorInterp=Green
>   Description = Band_2
>
> Band 3 Block=2215x1 Type=Byte, ColorInterp=Blue
>   Description = Band_3
>
> #------------
> $ grass75 -gtext
> # defind new location, LDQ, using above proj.4 string. Start grass and
run:
> r.in.gdal in=$HOME/path/to/data/45122c3307.tif out=south_area
> ERROR: Projection of dataset does not appear to match current location.
>
>        Location PROJ_INFO is:
>        name: unnamed
>        ellps: grs80
>        proj: lcc
>        lat_1: 46
>        lat_2: 44.33333333333334
>        lat_0: 43.66666666666666
>        lon_0: -120.5
>        x_0: 2500000
>        y_0: 0
>        towgs84: 0,0,0,0,0,0,0
>        no_defs: defined
>
>        Dataset PROJ_INFO is:
>        name: NAD83(HARN) / Oregon North
>        datum: nad83harn
>        ellps: grs80
>        proj: lcc
>        lat_1: 46
>        lat_2: 44.33333333333334
>        lat_0: 43.66666666666666
>        lon_0: -120.5
>        x_0: 2500000
>        y_0: 0
>        towgs84: 0,0,0,0,0,0,0
>        no_defs: defined
>
>        ERROR: datum
>
>        In case of no significant differences in the projection
definitions,
>        use the -o flag to ignore them and use current location definition.
>        Consider generating a new location from the input dataset using the
>        'location' parameter.
>
>
>>> Can I display this DLQ in color? (I think the last time I used aerial
>>> photographs or satellite imagery was with grass-4.1 or -5.x.)
>>
>>
>> Try d.rgb
>
>
>   Okay. Thanks.
>
>
> Rich
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