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topo map of NJ 1

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davshkl

Civil/Environmental
Nov 23, 2015
5
I just relocated to NJ, work with ... small land development firm. They use USGS map to determine storm drainage areas.
I am trying to find topo map of NJ with contours at least every 5'.
Does anybody knows website where I can download such map?
Thank you!
 
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Straight from the source:
==========
"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill
 
I appreciate time both you (God's representative "I can do absolutely anything. I'm an expert!" and History professor) took to respond to my question. I am sure, you know a lot, but, unfortunately, you missed the main point of my question - I am looking for the topo map with contours every 2 or 5 feet. Both suggestions go to USGS map with contours every 20' ...
PS. I just do not like arrogance ...
 
Data is available form the USGS. You will need to add the contours.

New Jersey - All counties are covered by LiDAR data with a vertical accuracy of 13-18.5 cm which supports 1-2 foot contours. Most of this data is available on the USGS National Elevation Dataset (NED) or CLICK websites.
 
You could download a 3D map from Google and import it as a geo-located image into Trimble SketchUp and then project planes through the image on 5' spacing and the intersection of the planes and the 3D image will be contours with 5' spaces. There is a video on You tube that shows how to do it. Search for 3D contour mapping.

Jim
 
Whoa, be careful "just adding contours". Mapping is created with specific tolerances in place. For instance the error associated (as I have been told) is typically +/- 1/2 contour interval. Just adding contours will not provide a reduction in error.

Lidar is a fairly good alternative; but, it also has its issues. One would need a processor to establish a bare ground model and then have the correct tools (ARCGIS or ?) to use it for hydrology.

You can always check with the Flood Control District or Transportation Department to see if they have more detailed mapping available at a small cost.
 
Can these USGS map be converted to ACAD format (DWG or DXF) and if so there is a LISP program that was developed a few years ago which I can research in my archive.
 
I'm not in NJ but for regional drainage, the USGS Urban and Rural Regression Equations can rely on the USGS topo map as presented. These are still allowed by my State DOT for bridge and culvert permitting, provided the watershed fits the limitations of the equations. I'd always check with the project's local municipality to see if they have more detailed mapping information available and what specific hydrologic modeling they require. BIMR mentioned NJ has all counties mapped in LiDAR, I'm thinking you can't beat that along with site specific topo.
 
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