[UW-GIS-L] ASCII to GRID
Harvey Greenberg
hgreen at u.washington.edu
Mon Jul 14 13:02:53 PDT 2003
The flip and mirror functions will fix your grid:
Grid: rename mygrid badgrid
Grid: mygrid = mirror(flip(badgrid))
harvey
MATSUOKA, Kenichi wrote:
> Hi
>
> Thanks Harvey and David. I successfully converted the ASCII file into raster,
> and geocoordinated (stereographic projection). However, I met another
> problem.
>
> The mapped data on ArcInfo was turned upside down and right side left.
> It looks like a printed map from the other side of the transparent paper.
>
> It may be caused by the order of data. The data set which I would like
> to use has an array "left bottom ---> right bottom ---> 2nd line from
> the bottom ---> ..... ---> right top".
>
> - Does Arcinfo treat the data set as "left top --> right top --> 2nd
> line from the top --> ..... -> right bottom" as a default? (Sorry, I
> donot have any manuals, but I only learn with help files)
>
> - When I add the data into Arcinfo, can I specify the order of the data?
> or can I change the default?
>
> - Otherwise, are there some tools to achieve my requirement?
>
> Sorry for some very basic questions. I hope that I am not of a nuisance
> so much.
>
> Thanks
>
> Kenny
>
> --------------------------------------------------------
> Projection:
>
> All grids are in a polar stereographic projection with reference to the
> WGS84 ellipsoid. The standard parallel is 71 degrees, and the projection
> parallel is 90 degrees north latitude. The North Pole is the origin of
> the projection. The central meridian is 39 degrees west longitude.
> --------------------------------------------------------
> Grid Description:
>
> Each grid consists of 301 columns and 561 rows, with data points
> gridded every 5 km and the origin at the North Pole. Corner points are
> as follows:
> Longitude Latitude x (km) y (km)
> Upper Left 92.130066 deg W 80.8151779 deg N -800 -600
> Lower Left 52.2405199 deg W58.6289678 deg N -800 -3400
> Upper Right 10.398705 deg E 81.5293986 deg N 700 -600
> Lower Right 27.3663654 deg W58.813316 deg N 700 -3400
> --------------------------------------------------------
>
>
> On Thu, 10 Jul 2003 22:47:36 -0700 David Finlayson <dfinlays at u.washington.edu> san wrote:
>
>
>>If you don't know ArcInfo (DESCRIBE is a command in ArcInfo), look at
>>the spatial tab on ArcCatelog to check the projection information.
>>
>>After loading the grid using Harvey's corrections below, you will then
>>need to use the Define Projection tool to teach arcGIS where in the
>>world your coordinate system is. I bet this is going to be a pain...
>>You need to know the projection, the spheroid, and the relationship
>>between your custom coordinate system and lat-long geographic
>>coordinates. Almost nothing works correctly in ArcGIS without doing
>>this final step.
>>
>>David
>>
>>
>>Harvey Greenberg wrote:
>>
>>
>>>You need a sixth header line for nodata, e.g.
>>>
>>>NODATA_value -9999
>>>
>>>and you weren't including the <brackets> in the file, were you?
>>>They do not belong.
>>>
>>>If you are giving the corners in latlong, the cellsize should be in
>>>latlong. However, You are working in some sort of metric projection.
>>>The CENTER of the lower left cell is (-800,-3400), but the corner
>>>is 2.5 km from there.
>>>
>>>so it's either:
>>>NCOLS 301
>>>NROWS 561
>>>XLLCORNER -802.5
>>>YLLCORNER -3402.5
>>>CELLSIZE 5
>>>NODATA_value -9999
>>>
>>>or (probably preferable)
>>>NCOLS 301
>>>NROWS 561
>>>XLLCORNER -802500
>>>YLLCORNER -3402500
>>>CELLSIZE 5000
>>>NODATA_value -9999
>>>
>>>
>>>After you import the file, DESCRIBE the grid to make sure
>>>the corners are right.
>>>
>>>harvey
>>>
>>>
>>>MATSUOKA, Kenichi wrote:
>>>
>>>
>>>>Hi
>>>>
>>>>Is anyone familiar with loading ASCII files into grids? I tried to use
>>>>ASCII to GRID tool in ArcTool box, but it did not work well and I met an
>>>>error message "An error occurred while running ASCII to grid. Unloading
>>>>the tool". I would appreciate for any kinds of advice. Detail of the
>>>>problem is below:
>>>>
>>>>1. What I want to do
>>>>Map Greenland DEM (ice surface and bed surface) and project it on some
>>>>geographic coordinations. The supplied data set is gridded by every 5 km.
>>>>--------------------------------------------------------
>>>>Grid Description:
>>>>Each grid consists of 301 columns and 561 rows, with data points
>>>>gridded every 5 km and the origin at the North Pole. Corner points are
>>>>as follows:
>>>> Longitude Latitude x (km) y (km)
>>>>Upper Left 92.130066 deg W 80.8151779 deg N -800 -600
>>>>Lower Left 52.2405199 deg W58.6289678 deg N -800 -3400
>>>>Upper Right 10.398705 deg E 81.5293986 deg N 700 -600
>>>>Lower Right 27.3663654 deg W58.813316 deg N 700 -3400
>>>>--------------------------------------------------------
>>>>
>>>>2. Header information
>>>>Based on the above description, I put the header information at the top
>>>>of the file.
>>>><NCOLS 301>
>>>><NROWS 561>
>>>><XLLCORNER -52.2405199>
>>>><YLLCORNER 58.6289678>
>>>><CELLSIZE 5>
>>>>
>>>>3. Delimiter of the data
>>>>HELP file adviced me that the cell values are space delimited. Also, I
>>>>changed the delimiter with space, comma, and tab, but nothing changed.
>>>>4. Unclear points.
>>>>- I cannot catch the exact meaning of the error message. Do I need
>>>>install the tool? I met the message when I choose input/output files and
>>>>execute it (pushed OK button). Then, I think the tool is still installed.
>>>>
>>>>- I cannot understand how CELLSIZE works. What is the unit
>>>>(kilometers/meters/unitless) of the cellsize? If it is unitless, how is
>>>>longitude/latitude for each cell obtained?
>>>>
>>>>Thanks
>>>>
>>>>Kenny
>>>>
>>>>---------------------------------------------
>>>>MATSUOKA, Kenichi <matsuoka at ess.washington.edu>
>>>>
>>>>
>>>>_______________________________________________
>>>>Uw-gis-l mailing list
>>>>Uw-gis-l at u.washington.edu
>>>>http://mailman.u.washington.edu/mailman/listinfo/uw-gis-l
>>>
>>>
>>>
>>--
>>David Finlayson
>>School of Oceanography
>>Box 357940
>>University of Washington
>>Seattle, WA 98195-7940
>>USA
>>
>>Office: Marine Sciences Building, Room 112
>>Phone: (206) 616-9407
>>Web: http://students.washington.edu/dfinlays
>>
>>_______________________________________________
>>Uw-gis-l mailing list
>>Uw-gis-l at u.washington.edu
>>http://mailman.u.washington.edu/mailman/listinfo/uw-gis-l
>
>
> ---------------------------------------------
> MATSUOKA, Kenichi <matsuoka at ess.washington.edu>
>
>
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--
hgreen at u.washington.edu 162 Johnson Hall 206-685-7981
http://duff.ess.washington.edu/
Harvey Greenberg
University of Washington
Department of Earth and Space Sciences
63 Johnson Hall (Box 351310)
Seattle WA 98195-1310
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