topic Re: Cant get .asc files to display as dtm in Data Management Questions

Cant get .asc files to display as dtm

GeospatialTechnology — Tue, 31 Jan 2012 17:14:32 GMT

Hello, Ive been trying to get a couple of .asc files to open in ESRI ArcGIS.

They are a sample demo of some dtm data.

Any idea how to create a dtm raster with them. I've tried ASCII to Raster but keep getting an error message saying they are not suitable.

Thanks for any help!

Re: Cant get .asc files to display as dtm

TarunJaiswal — Tue, 31 Jan 2012 18:01:21 GMT

Hi Mark,

The ASCII file must consist of header information containing a set of keywords, followed by cell values in row-major order, in order to be read by ArcGIS.
As per help documentation the file format for ASCII is as follows:

    <NCOLS xxx>
    <NROWS xxx>
    <XLLCENTER xxx | XLLCORNER xxx>
    <YLLCENTER xxx | YLLCORNER xxx>
    <CELLSIZE xxx>
    {NODATA_VALUE xxx}
    row 1
    row 2
    .
    row n

Please check and see if your ASCII files have the header information stored as mentioned above.

Thank you.

Re: Cant get .asc files to display as dtm

GeospatialTechnology — Wed, 01 Feb 2012 10:17:24 GMT

Sorry my bad i was being lazy and trying to drag and drop the .asc file into the tool dialog box. It worked fine when i opened it up from within the ASCII to Raster toolbox!

Thanks for your help!!

Re: Cant get .asc files to display as dtm

GeospatialTechnology — Wed, 01 Feb 2012 10:23:39 GMT

Sorry my bad i was being lazy and trying to drag and drop the .asc file into the tool dialog box. It worked fine when i opened it up from within the ASCII to Raster toolbox!

Thanks for your help!!

Re: Cant get .asc files to display as dtm

DustinEdge — Thu, 12 Apr 2012 23:11:07 GMT

Same problem here. It works if I use the Browse button to navigate to the folder that contains the ascii, but it bombs when I try draggin & dropping the ascii into the tool window or even when in batch mode.
This worked fine in 9.3.1 so I'm guessing another ESRI bug..

Cheers
Dustin

Re: Cant get .asc files to display as dtm

EricRice — Thu, 12 Apr 2012 23:32:27 GMT

Dustin,

Why bother to run ASCII to Raster in the first place? An ASCII file formatted like the one Tarun outlined, should already be recognized as a raster dataset. That tool is a legacy tool and was only needed for the days when we couldn't read ASCII files representing raster data as actual raster datasets. All you probably have to do is build statistics on the .asc file, define the projection, and it will render as raster data in ArcMap. To confirm this you can run the Raster to ASCII tool to output an .asc file. Then hit Add Data and browse to where the file is on disk. In the Add Data dialog your .asc file should already have a raster dataset icon.

If you don't want the data in that format, just use the Copy Raster tool to change the format.

Regards,
Eric

Re: Cant get .asc files to display as dtm

LinaMENG — Sun, 03 Feb 2013 06:33:38 GMT

Hi Mark,

The ASCII file must consist of header information containing a set of keywords, followed by cell values in row-major order, in order to be read by ArcGIS.
As per help documentation the file format for ASCII is as follows:

    <NCOLS xxx>
    <NROWS xxx>
    <XLLCENTER xxx | XLLCORNER xxx>
    <YLLCENTER xxx | YLLCORNER xxx>
    <CELLSIZE xxx>
    {NODATA_VALUE xxx}
    row 1
    row 2
    .
    row n

Please check and see if your ASCII files have the header information stored as mentioned above.

Thank you.

Thanks for your sharing!
I am wondering that how to import an ascii file without the header information? the file is stored as following:

0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00

the author of the dataset claims that it is exactly the file structure of an ascii file and allowed to import into arcgis.