topic Re: Having trouble importing contour data using usgs website in Civil 3D Forum

Having trouble importing contour data using usgs website

Anonymous — Sat, 15 Sep 2018 02:59:04 GMT

I was able to import contour data from the usgs website. However, the quad of contours is 1 ft x 1 ft and it is not georeferenced correctly. Do you have any ideas what I'm doing wrong?

Re: Having trouble importing contour data using usgs website

Pointdump — Sat, 15 Sep 2018 11:38:14 GMT

Joaquin,

Welcome to the Autodesk Forums.

Need more information. What is your data and how were you importing it? Can you post your data, or a link to it?

Dave

Re: Having trouble importing contour data using usgs website

ChicagoLooper — Sat, 15 Sep 2018 11:38:45 GMT

Please describe the ‘contour data’ because that could mean different things. Vector data? Raster? And downloaded from where on USGS website? URL?

Re: Having trouble importing contour data using usgs website

Anonymous — Sat, 15 Sep 2018 15:02:45 GMT

Hi ChicagoLooper,

Thanks for your reply. I really do appreciate it. This is the web link where I downloaded the file from

https://viewer.nationalmap.gov/basic/#productSear

The download:

USGS NED n32w099 1 arc-second 2013 1 x 1 degree ArcGrid

I attached the c3d file with the topo and the file (from usgs website) I used to create the contours.

The contours don't seem to be in real world scale and not georeferenced correctly. Not sure what I'm doing wrong.

Any help would be greatly appreciated!

Re: Having trouble importing contour data using usgs website

Anonymous — Sat, 15 Sep 2018 15:11:53 GMT

Thanks for your reply Dave. The site I used is the following:

https://viewer.nationalmap.gov/basic/#productSearch

USGS NED n32w099 1 arc-second 2013 1 x 1 degree ArcGrid

The file I used to create get contours is called w001001.adf

I have attached the c3d file if that helps.

Any help is appreciated!

joaquin

Re: Having trouble importing contour data using usgs website

ChicagoLooper — Sat, 15 Sep 2018 17:10:15 GMT

Unfortunately i don't think you have contour data,. What you've downloaded is an elevation product., such as a 1 arc-second DEM, in NAD83 datum, Lat/Long format, which is a raster. USGS doesn't have anything named 1 ft x 1 ft contours. Also, the USGS DEMs are not in quads. If you want data from a quadrangle, you need to go to the Topo Map Data and Topo Stylesheet section. To get contour 'lines' you'll need to get the Elev_Contour shapefile. You can either use the shapefile as-is or import it and convert it to cad line work during in the import process.

1-Get the shape file here.2-From the downloaded quad, you'll get a variety of shapefiles.

3-DEM, 1x1, example 1, color themed.4-DEM, 1x1, example 2, USGS color palette.

As you can see, there are possibilities when using DEMs. You can even combine the DEM with contour lines.

Re: Having trouble importing contour data using usgs website

ChicagoLooper — Sat, 15 Sep 2018 17:23:04 GMT

They are georeferenced to NAD83 lat/long or EPSG 4269. If you are drawing in state plane, assign your state plane to modelspace. When you use data connect to connect to the elevation raster (that super big file that with begins with w001 and ends with extension .adf) make sure the raster has a coordinate system LL83 (EPSG4269). If it doesn't you'll need to edit the raster so that it does. It's perfectly OK if the 'input' coordinate system doesn't match the modelspace coordinate system--they don't have to match because Civil3D/Map3D will perform a transformation for you.

If you want the get the contours directly from the quad, you can do that too from the USGS webite. You may, or may not, have to get more than one quad and put the quads side-by-side if you have a wide coverage area.

Re: Having trouble importing contour data using usgs website

Pointdump — Sun, 16 Sep 2018 10:30:27 GMT

Joaquin,

Well, that DEM is a Monster! 13 million points! And C3D stores that huge surface in an external "MMS" file. (483 MB's!)

I'm guessing the step you missed was identifying the Coordinate System of that DEM. Thusly:

Dave

Re: Having trouble importing contour data using usgs website

Anonymous — Sun, 16 Sep 2018 17:47:33 GMT

Thanks for the feedback Dave. I wasn’t intending for the file to be that large! I got some learning to do. Do you have any suggestion on where and how to get topo data?

Re: Having trouble importing contour data using usgs website

Anonymous — Sun, 16 Sep 2018 19:01:33 GMT

Thanks! This is more complicated than I thought. I guess I"m not
understanding everything.

I guess, I should explain what I'm trying to do and maybe you have a better
suggestions how to approach.

I have a 300 acre piece of property and I like to show contours on this
property so that I can work on the grading and drainage.

I'd like to be able to use this contour information to create a surface as
necessary in the future.

Do you have a suggestion how I should do this?

joaquin

Re: Having trouble importing contour data using usgs website

ChicagoLooper — Sun, 16 Sep 2018 20:32:10 GMT

Looks like you're in Brown County. When I work with contours downloaded from the USGS site, you must understand that these contours are (1) NOT survey grade and (2) they cover a wide area. Do you have the lat/long of the 300-ac site? Simply 'eyeball' the center and get the lat/long. Once you provide the lat/long I can give you two options. Keep in mind, the downloads from USGS are NOT survey grade--to get survey grade you need a surveyor--no exceptions.

Re: Having trouble importing contour data using usgs website

Anonymous — Mon, 17 Sep 2018 01:49:33 GMT

Completely understand contours are not survey grade. I just need a
starting point to get a general feel for the terrain. I opened google
earth and the coordinates I got are the following, 31d06'42"N 98d01'52"W.

I really do appreciate all your great feedback.

joaquin

Re: Having trouble importing contour data using usgs website

Pointdump — Mon, 17 Sep 2018 10:42:32 GMT

Joaquin,

To tame that Big Ol' DEM (Texas Talk), add a Data Clip to your Surface Definition before bringing in the DEM.

For more Elevation Data you can check >>>TNRIS<<<.

Edit: Looks like the TNRIS Site doesn't have Elevation Data, but you might still find something useful there.

Dave

Re: Having trouble importing contour data using usgs website

Anonymous — Mon, 17 Sep 2018 10:38:07 GMT

I haven't downloaded data from USGS for a while, but you used to be able to select the download area by clicking on the map defining a rectangle in order to limit the data. Look for the best data (1/9"), then the next best (1/3"), etc. till you get the best data available for your 300 acres. You can get ortho photos, among other data categories, at the same time, if you want them.

Re: Having trouble importing contour data using usgs website

Pointdump — Mon, 17 Sep 2018 11:08:38 GMT

Joaquin,

This is fun. After further nosing around in TNRIS, if you search in the Kempner Quadrangle you'll find Contours and Elevation Points covering your ranch. They may or may not be any better than the data from the USGS site.

Dave

Re: Having trouble importing contour data using usgs website

ChicagoLooper — Mon, 17 Sep 2018 12:46:51 GMT

You can easily get the contours from the same USGS site, but instead of downloading w0001001.adf from n32w099 which is an Elevation Product (Raster 1mx1m), you should download from Topo Map Data and Topo Stylesheet instead.

If you download the raster, regardless of how small the raster is, you'll still have to generate the contours from the raster. By downloading the Topo Map Data and Topo Stylesheet, you'll get the contours immediately, albeit as a shapefile. If you wish, you can even import the shapefile to C3D/M3D and automatically convert them into Cad polylines during the import procedure which will conveniently allow you to work exclusively with Cad entities and not a combination of Cad and ESRI objects.

To get the contours without dealing with that huge raster, follow the ATTACHED INSTRUCTIONS.

Re: Having trouble importing contour data using usgs website

ChicagoLooper — Mon, 17 Sep 2018 15:42:05 GMT

To further illustrate why you should download contour shapefile and not elevation data, see image-1.

1-Get shapefile from Topo Data Map and Topo Stylesheet.

The elevation data is the green raster, and the contours, which are yellow, are vectors and are limited to the extent of a 7.5 minute topo quadrangle, in your case Kempner Quad. If you download the raster, you're getting more data, way more data, than you need, image-2. You can make contours from the raster but why do that when you can get download the contour shapefile itself?

2-Raster vs. Contour Shapefile.

The example below illustrates both raster and the vector data (contours) overlaid one another. You can clearly see the contours are more than sufficient in providing the necessary coverage for your 300-acre site. The aerial photo with the blue parcel boundaries was downloaded from Lampasas County Central Appraisal District (lampasascad.org), View County Maps. The RED geomarker, labeled The Site, is in the middle of your project and was located using the coordinates you provided in post #12. If you look closely at image-2 above, you can see the RED geomarker amongst the yellow contours.

3-The Red geomarker is in the middle of your 300-acre parcel. Yellow contours provide more than enough coverage.

Re: Having trouble importing contour data using usgs website

Anonymous — Mon, 17 Sep 2018 20:40:35 GMT

Thanks for the great help!

Re: Having trouble importing contour data using usgs website

KirkWM — Mon, 17 Sep 2018 22:30:56 GMT

Great discussion! I'm a bit rusty on this one and the refresher is helpful.

Re: Having trouble importing contour data using usgs website

Anonymous — Tue, 18 Sep 2018 01:47:53 GMT

Thank you so much for this information Dave! I followed your good instructions and it totally worked. The boundary clip was super helpful and no longer bogs down my computer.

I do have one quick question. How did you determined the CS code for the DEM file?

joaquin