How do I import this .ASC file?

[zacharydK32M8]

I have this .ASC file but when I import as DEM, civil3d says it's an invalid DEM file.

Anybody seen something like this before?

Thanks for your time

[pendean]

https://forums.autodesk.com/t5/civil-3d-forum/import-dem-asc-files/td-p/8854720

[Pointdump · Accepted solution]

That's not a DEM. It's just a regular PENZD or PNEZD point file.
Dave

[Pointdump]

A DEM ascii file is arranged like this:

NCOLS xxx
    NROWS xxx
    XLLCORNER xxx
    YLLCORNER xxx
    CELLSIZE xxx
    NODATA_VALUE xxx
    row 1
    row 2
    .
    .
    row n

And looks like this:

Dave

[ChicagoLooper]

Assuming you know what you want to do with your ASC, you can do this:

1. On commnad line, type in MAPCONNECT. File button=>browse to your ASC file=>Connect. Refer to image-1.
2. Verify the native coordinate system given to the ASC file by its original author is being read correctly. Image-2
3. MAPWSPACE on command line. Choose 'ON' from options. The ASC will be listed in the Map Task Pane. Image-3.

Image-1

Image-2

Image-3

.

[ChicagoLooper]

Are you trying to create a surface? For Files of type change to *.asc using the dropdown menu.

[wfberry]

Like Dave said:

This is just a text file with a "non existent" coordinate system.  It is a coordinate system, however, it is based on a beginning of 5000, 5000.  We used to do this all the time before GPS.

You can make a surface out of it but you will need to know where it is located.

Bill

[AllenJessup · Accepted solution]

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@zacharydK32M8 wrote:

Anybody seen something like this before?

I see them all the time. As mentioned. This is a comma delimited PNEZD or PENZD file. Use Insert > Import > Points from file.

However. I don't see any valid elevations in your screenshot. So. Unless there are valid elevations further down in the file. It will be useless in creating a Surface.

[ChicagoLooper]

Nope, it's not a text file. It's an ESRI ASC file.  It's a GIS type grid file, not a civil file. 

And no it's not a non-existent coordinate system. The coordinate  system is could be UTM or specific to the country's location. And the location may, or may not be in the US so it doesn't have to be in State Plane.

[AllenJessup]

@zacharydK32M8 

Can you post the file or a part thereof? That way we can see what it actually is.

[zacharydK32M8]

Thank you all for this helpful discussion. I'll have to give all of your suggestions a try.

I've attached the original file in this post. I had to change the .asc to .txt in order to upload.

[AllenJessup]

Our Leica equipment exports ASCII point files with an ACS extension.

From http://docs.mcneel.com/rhino/5/help/en-us/index.htm#fileio/points_file_asc_csv_txt_xyz_cgo_import.ht...

[AllenJessup]

OK. PNEZD or PENZD. Once you get to point 300. You have elevations that could be used to create a Surface. Try PNEZD first and see it the points look like the area of interest. Or contact the originator to find out which format it is.

[ChicagoLooper]

Huh? You are manipulating the file(s).

This is a txt file. It's not an ASC file.

When looking, at the file displayed in your opening post, it has an .ASC extension. This one has .txt extension. I'm thinking the original file in the opening post might not even be the original ASC file.

Please post the original unadulterated ASC file, not a copy. BTW, the real ASC has an ASC extention, not one with a txt extension.

[zacharydK32M8]

The forum wouldnt let me upload .asc format.. I had to change it to .txt in order to upload it.

In my opening message I had opened the .asc in Notepad since I don't know how else to open it.. is that misleading?

[AllenJessup]

@zacharydK32M8 

Zip the file. That will allow you to post it with the original extension.

[Pointdump]

Zachary,
As Allen says, if you Zip your file this Forum will accept anything.
20+ years ago, Survey Pro on the HP48 used to store points in CR5 format. To get them into AutoCAD R14/Softdesk you had to use Survey Link, which converted the CR5 into an ASC format. ASC is exactly the same as TXT format.
Dave

[AllenJessup]

I have thousands of .ASC files. They're all PNEZD point files.

[ChicagoLooper]

This may, or may not, be your exact workflow. Nevertheless, it is 'a' workflow that demonstrates how to go from a .txt formatted point file to an .ASC grid file then to AutoCad.

Using GLOBAL MAPPER: How to create an ASC file using a txt.

1. Add the data. In this particular example a txt file in excess of 285,000 points. (Global Mapper can consume various ASCII files in various formats.) <<BTW, GloMap is not freeware and IDK if QGIS, which is free, has the same capability but maybe Mr @Pointdump  can offer his expertise.>>
2. Create a GRID then Export the GRID file to ASC. 

1-This is a txt file that's opened using Excel. This file is the basis for this 'how to' demonstration.

2-This is the exported ASC file opened in Global Mapper. This is the same file that can be read and used in AutoCad. (The imagery, csv and grid layers have been turned off.)

Change the workspace to Planning & Analysis. Using the Data Connect palette, the ASC data is added as a raster. The ASC is in modelspace and is also displayed in the Map Task Pane on the right. If you don't like the green blob, you can use the Map3D toolset and use a 'theme' to display the ASC, such as a color oriented elevation theme. Themes vary according to the ASC's inherent data so you may, or may not, have more options beyond an elevation theme.

3-The ASC added to the dwg using a Data Connection.

Alternatively, you may use the ASC as a definition for your TINN surface.

4-You can create a surface.

Here's the surface.

5-The ASC was used for the TINN definition.

Using the point file displayed in image-1 above, you can also use it to create EG, a TINN surface. What are the similarities of image-5 and image-6?

6-Surface created by the point file itself.

[tcorey]

No one mentioned it, so I will. The screenshot you posted shows all points at elevation -999999. This indicates a null elevation. If you're trying to use this file to create a surface, it is not going to work.