Hunterra maps and higher resolution topos

Turkish

Active Member
First, is there a source online for maps that have higher resolution topographic data than the standard USGS topos? I think the USGS topos for my area have contours every 10 feet — where can I get them for, say, 5 or less?

I have it in my head that Hunterra maps provide this, if you purchase from them, but I don’t know. Can anyone confirm?
 
This is kind of a tricky question. The validity of the contour lines is solely dependent on the quality of the digital elevation model (dem) used to determine the lines. We have gone from 30 meter dems to 10 meter dems to 3 meter dems and now LIDAR with sub one-meter accuracy.
It's possible to make a topo map with 5 foot contours using a 30 meter digital elevation model, but the contour lines are simply equal interval spacing between the most accurate level of detail. So, you might have the illusion of accuracy where you do not. On the other hand, a highly accurate 1 meter LIDAR model will twist and turn every contour line to the point where it's hard to interpret. So, good luck.

Check with your county GIS department. Today, a lot of them can custom produce what you're looking for. With the right models and software it takes about 60 seconds.
 
Yep yep. Done some research. I have LIDAR data for my area. Now to better understand how to convert .las to a file type I can use, hopefully in Google Earth.
 
naip.jpg hillshade.jpg contour.jpg topo.jpg A .las file is just the beginning. It is used in conjunction with a bushel of other files to create a surface model. There are services (for pay) that will convert the entire set so you can use it in Google maps. But, I still wonder if 5 ft contours are what you need. It may be, but they are mostly used for doing cut and fill work.

The images below are for your consideration. The scale on all of them is 1:9600 (1 inch = 800ft). Throw something at the wall and see what sticks? It's a small area somewhere here in Virginia. Aerial imagery is NAIP. A hillshade is the 3D looking image. It's derived from LIDAR data. I didn't include a picture of the raw LIDAR. Maybe the hillshade is what would best serve your interests. I'm assuming a lot, I know. Then, for comparison, I put 5 ft contour lines on the hillshade. The final image is of a standard USGS topo. All are of the same area.

Whatcha think?
 
Thanks. Maybe the hill shade would suffice. I could get by without contours. I’d just like a little better topo data than USGS topos offer.
 
This is kind of a tricky question. The validity of the contour lines is solely dependent on the quality of the digital elevation model (dem) used to determine the lines. We have gone from 30 meter dems to 10 meter dems to 3 meter dems and now LIDAR with sub one-meter accuracy.
It's possible to make a topo map with 5 foot contours using a 30 meter digital elevation model, but the contour lines are simply equal interval spacing between the most accurate level of detail. So, you might have the illusion of accuracy where you do not. On the other hand, a highly accurate 1 meter LIDAR model will twist and turn every contour line to the point where it's hard to interpret. So, good luck.

Check with your county GIS department. Today, a lot of them can custom produce what you're looking for. With the right models and software it takes about 60 seconds.

Good info. You know your maps.
 
Thanks. Maybe the hill shade would suffice. I could get by without contours. I’d just like a little better topo data than USGS topos offer.

Hillshade was added on online here, a few years ago. I was astounded at what it showed. You can see glacial flows, etc. Down on the plain, there were N-S ridges I had no idea were there from any other source. Even when on the ground they weren't obvious but can bet deer know. Between them and the E-W beaver ponds it opened a new world of possibilities. However, the lidar is so fine scale it can make mountains out of molehills that are hard to see on site.
 
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