Playing with Digital Elevation Models

Cartography, maps, navigation, GPS and more.
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aiwetir
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Playing with Digital Elevation Models

Post by aiwetir » March 17th, 2018, 12:06 am

Started messing with Lidar DEMs in school last week and it occurred to me that there are a lot of popular places with crappy topo maps out there. Saddle Mountain, Multnomah Falls and the one to the west of that. So I threw this together tonight. I even traced out the trail because you can clearly see it in the bare earth hill shading. Lidar is a magic tree eraser. Anyway here's one map, I'll throw some together next week after finals. Will take requests, may compile them onto one site if people show any interest.

Oh, hey, regular disclaimer, don't go walking off a cliff because you are using my map.

Image
- Michael

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retired jerry
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Re: Playing with Digital Elevation Models

Post by retired jerry » March 17th, 2018, 5:37 am

Nice map, thanks, that came out really good

RobFromRedland
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Re: Playing with Digital Elevation Models

Post by RobFromRedland » March 17th, 2018, 6:40 am

I'm curious - where can you find public LIDAR data?
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aiwetir
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Re: Playing with Digital Elevation Models

Post by aiwetir » March 17th, 2018, 8:17 am

RobFromRedland wrote:I'm curious - where can you find public LIDAR data?
https://gis.dogami.oregon.gov/lidarviewer/

It's a little unintuitive, but you have to have the Downloadable Lidar Data layer on, click on a layer and then dig into the menu sometimes.
- Michael

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Peabody
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Re: Playing with Digital Elevation Models

Post by Peabody » March 17th, 2018, 1:12 pm

aiwetir > Nice map.

RobFromRedland > Washington also has a Dogami style viewer now.

http://lidarportal.dnr.wa.gov/
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aiwetir
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Re: Playing with Digital Elevation Models

Post by aiwetir » March 17th, 2018, 5:32 pm

Peabody wrote:aiwetir > Nice map.

RobFromRedland > Washington also has a Dogami style viewer now.

http://lidarportal.dnr.wa.gov/

I meant to link to that too
- Michael

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Re: Playing with Digital Elevation Models

Post by Webfoot » March 17th, 2018, 8:54 pm

How are you producing these contour lines? Could the process be scaled to large areas? I ask because it would be nice to have high resolution contour lines in OSM products, like those available from https://www.openandromaps.org/ which I use for primary navigation.

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aiwetir
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Re: Playing with Digital Elevation Models

Post by aiwetir » March 17th, 2018, 10:27 pm

Webfoot wrote:How are you producing these contour lines? Could the process be scaled to large areas? I ask because it would be nice to have high resolution contour lines in OSM products, like those available from https://www.openandromaps.org/ which I use for primary navigation.
I built these in QGIS, a gis application (which is free btw). I too have been searching for about 3 years for a high quality topos. I thought MapBox was the OSM solution, but they stopped updating regularly and I see stuff getting close to 6 months old in MapBox now. I'm taking a web mapping course next term and will be inquiring about methods to do this, starting small and seeing if I can slowly scale up without breaking the web server bank.

It's one of the reasons I went back to school, there are so many ways to have good maps now, but no one has quite put it all together yet in the way I envision it 'should' be (good topography, frequent OSM data updates, vector graphics, local storage, storage for personal geospatial data). That product is probably a lifetime of work to produce, but maybe if I can do it small scale, someone can scale it up for me or buy my ideas.

But specifically it probably is quite scalable, it uses gdal and a simple command

Code: Select all

gdal_contour -i 10.0 input.tiff output.shp
.

You would then have to convert the shp file into something the server could deliver and the device could read.


In the mean time, I'm going to keep playing with these tools and try to make some nice usable maps. I'll add more features to this one too. I did it in just a few minutes just to see how it looked.
- Michael

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retired jerry
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Re: Playing with Digital Elevation Models

Post by retired jerry » March 18th, 2018, 5:36 am

interesting subject, thanks

why do you need frequent updates?

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aiwetir
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Re: Playing with Digital Elevation Models

Post by aiwetir » March 18th, 2018, 10:17 am

retired jerry wrote:interesting subject, thanks

why do you need frequent updates?

Because I can :D

That's most of the reason, but I've done so much mapping on OpenStreetMap that it's nice to see the changes appear by the time I want to use them. There are a lot of inaccuracies on old USFS maps and because we can update maps, more temporary things (business listings) are starting to show up (food carts at JRO) that maybe need to be removed then they are gone/changed. So the updating process is more important with OSM. Google controls their maps, they make an update, it shows up worldwide. OSM data is downloaded and presented by many companies who want to customize its appearance and features, these end up getting stale in many places.
- Michael

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