11 replies to this topic

[Ted Florence]

Over here at Avenza we are wondering about people's use of DEMs.
How many of you out there use DEMs and what do you do with them?
What kind of operations do you run on them?
What software do you use to work with them?
What kind of things would you like to do with them?
Thanks in advance for your feedback.
Ted

[Rob]

Over here at Avenza we are wondering about people's use of DEMs.
How many of you out there use DEMs and what do you do with them?
What kind of operations do you run on them?
What software do you use to work with them?
What kind of things would you like to do with them?
Thanks in advance for your feedback.
Ted

Main uses: create hillshades, slope models, generate contours, line of sight analysis, before and after grading plans, the basis for drapes.
Operations: smoothing, intervisibility, controlled generalizations, etc.
Software: ArcGIS, Leveller, VNS, Photoshop
Perhaps I can't think outside the box enough right now, but I like what I already do with them.

Edit: and like Rusty, we do profiles as well.

[Rusty]

Hi..first reply in this group!!!

Working with pipelines we use them to generate profile points along the centerline. We also generate spill plumes using NED and NHD layers. ASA has an ext. called OilMapLand along with spatial analyst to perform these tasks...
Creating contour lines to use on maps is another one...

there's an ext. called Crossview that uses elev. grids that produces other profiles I just started looking at...

Rusty
EMPCo

[frax]

Usage is primarily as a backdrop for maps, as shaded relief and sometimes with hypsometric tints. I use ArcGIS for the data processing and photoshop for the presentation.

Issues and challenges:

• I often go overboard with the resolution, which adds a lot of time, cpu cycles and frustration: and one often needs to downsample anyways. It also makes it harder to tweak in Photoshop.
• With a lot of manual tweaking in Photoshop, it makes it harder to make two maps next to each other to look similar.
• All the parameters in Photoshop also makes the presentation quite a time consuming process.

[Dale Sanderson]

How many of you out there use DEMs and what do you do with them?

I use DEMs to create shaded relief backgrounds for street maps. Currently my process is to bring them into MacDEM to generate tif images, then Photoshop to edit/finalize the images.

[Dennis McClendon]

Same as Dale. I search out the now-hard-to-find 250K tiles, run them through MacDEM, tweak the output shaded relief in Photoshop, and then try to register it to lat-long lines on a basemap drawn in FreeHand. I pretty much have to use a Mercator projection so they will register. That's not problematic for the small areas we map, but it can be tricky to get the other source maps (such as 250K topos or scans from atlases) in that projection. If I'm doing a big chunk of the world (1000 x 1000 km) I sometimes have to start with the DEM and draw the rivers and coastlines to fit, then try to fit roads and towns and boundaries to those.

[Hans van der Maarel]

Using DEM data to produce hillshades in VNS and Photoshop. Those hillshades are then used as a map background, placed in Illustrator as a GeoTIFF or PSD.

[Adam Wilbert]

same as others above, I generate hillshades in ArcMap, then export tiffs of both the Hillshade and the original DEM for tweeking in Photoshop. I use the original DEM as a layer mask, sometimes inverting the color ramp, sometimes adjusting the curves / contrast / etc to select elevation ranges for coloring. I also use the grayscale hillshade as a mask of itself too, to isolate shadow and highlight areas for more refined tinting. Dozens of adjustment layers later I've got my final render!

Consistency across multiple maps in a series is the hardest part about that particular workflow though, as grayscale values range from 0 to 255 regardless of the low / high elevation values on that particular sheet. If there were a way to preserve elevation information instead of just arbitrary grayscale value, that would rock!

[Simmer]

I use them for Flight Simulators, see here:

[Lui]

Hmm where to start? Firstly I'm producing hires DEMs from LIDAR data. I'm using DEMs to produce hillshading, static and dynamic visualizations, flood simulation, solar and enviroment studies, quantity calculations and contour production. Well contours are usually produced directly from LIDAR points or TINs. I'm also using DEMs in hillshading algorithm development and in orthofoto pruduction.
Software where DEM is directly in use: ArcGIS, Erdas Imagine, Terrasolid products, Leveller, VNS, Photoshop, Saga GIS,...

[mattg]

Hi..first reply in this group!!!

Working with pipelines we use them to generate profile points along the centerline. We also generate spill plumes using NED and NHD layers. ASA has an ext. called OilMapLand along with spatial analyst to perform these tasks...
Creating contour lines to use on maps is another one...

there's an ext. called Crossview that uses elev. grids that produces other profiles I just started looking at...

Rusty
EMPCo

How did Crossview work?

[RonInNJ]

Contours, profiles for geologic cross sections out of ArcGIS. We plan on using for shaded relief.

Ron