Canadian DEMs

[quakers1]

Hello everyone. I was wondering something. I know there have been people in the past that have made alot of US DEMs, but I was wondering something. Is there someone(past or present), that has made alot of Canadian DEMs? And is there anyone who knows how to make Canadian DEMs? If there are, please tell me who they are and I will take things from there. Thanks for reading this.

-quakers1

[robby2]

I had tried to do a DEM of the Bathurst NB area using the DEM data from the Geogratis web site. Since I am not that experienced with MicroDEM and HOG I was not really able to get that to work well. The other complication was that I could not determine where on the terrain to put things like roads and track. In the US they have the TIGER data that can be matched to the DEM data in MicroDEM which then gives lines on the terrain to trace tracks and roads on. In Canada it appears that we don't have that type of data...

I then tried to use an approach suggested by another of using digital TOPO maps by tracing the contour lines onto a blank layer and filling in different shades of black for different elevations. The HOG program then interprets the blackest shade as the lowest level and the whitest shade as the higher. Then what I did for the roads and track was to use the road outlines on the TOPO maps to draw a new blank layer with just lines of different colors.

That didn't work as well either because for some reason the terrain appears as streched, being the length would be way too long on the terrain than what it actually was. That made it hard to replicate an exact model of my area.

So there is my story of Canadian DEM attemps. If you figure out a better way to get this done let me know because I would love to knock out the extra time needed to create a more accurate route.

Robby

[geophil]

You can process Canadian DEMs (http://www.geobase.ca/geobase/en/) with TransDEM. TransDEM is payware.

Canadian DEM resolution for many areas is 0,75 arc sec, which is 20 m. There is no TIGER for Canada, but topographic maps 1:50000 in gif format are downloadable from http://toporama.cits.rncan.gc.ca/toporama_en.html. TransDEM can process those. Scanned paper maps 1:50000 are available as tif from the geogratis site. They show more detail than their gif counterparts but need an extra georeferencing step in TransDEM.

According to the feedback I receive, several Trainz route builders have used these resources.

geophil

[quakers1]

Thanks guys. I'm glad Canadian DEMs are possible. I am looking for a route in Canada to do and I was just wondering if Canadian DEMs are even possible before I request one. Now I know they are. Thank you for all of your help.

-quakers1

[Vern]

Sorry to bump, but further to my earlier post I can confirm Geobase does let you download DEM data for Canada free once you've registered.

Roland - how does this "1:50,000" data compare with our standard 90m European data? Better or worse?

Just downloaded some data for the Vancouver area as I'm thinking about taking a crack at a section of the British Columbia Railway for my next project.

[geophil]

Hi Vern,

Non-US SRTM DEMs are 3 arc sec or approximately 60 x 90 m for our latitudes.

Canadian "1:50000" DEMs are 0.75 arc sec or approx. 15 x 22m.

geophil

[Vern]

That sounds very promising then, particularly for the rugged coastal mountains around Vancouver Bay. Next step is to figure out how to grab the maps off Geogratis at a reasonably useful scale.

[Vern]

Update to above - got the maps downloaded, quite amazing that such quality is free of charge albeit this is for non commercial use.