OruxMaps

Uncategorized Boards => MAPAS/MAPS => Topic started by: febs on June 13, 2014, 02:52:19 PM

Title: Is this a new DEM?
Post by: febs on June 13, 2014, 02:52:19 PM

I just stumbled upon *this* and it looks very interesting.



What do you think about it?



http://courses.neteler.org/eu-dem-new-digital-surface-model-at-25m/



Cheers!

Title: Re: Is this a new DEM?
Post by: Zaidín on June 13, 2014, 08:28:38 PM

I have take a quick view and my first opinion is that it is not very approapiated for Oruxmaps:

    - Too heavy size archives (more than 1 gigabyte)

    - The format archives is not compatible (tiff). OM only accepts hdr format.

    - You can get similar dems through "dem1" app.



     This dems are more  appropiate to view on pc.

Title: Re: Is this a new DEM?
Post by: febs on June 14, 2014, 09:20:44 PM

Well, formats can be converted an big tiles can be splitted in smaller parts.  I was rather wondering how the accuracy compares with the DEM1 ones. I tested this EU-DEM on QGis and it looks quite good; although I didn't compare it yet with a DEM1.



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Title: Re: Is this a new DEM?
Post by: febs on June 14, 2014, 09:38:23 PM

Here's some contour lines that I generated from it. I know the area quite well and they look very good to me for being generated from a free DEM.



I am quite excited about this because very often when I "correct" the altitude of my tracks using the DEM1 models, I get very wrong results.



(//%3C/s%3E%3CURL%20url=%22http://img.tapatalk.com/d/14/06/15/7enyjama.jpg%22%3Ehttp://img.tapatalk.com/d/14/06/15/7enyjama.jpg%3C/URL%3E%3Ce%3E)



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Title: Re: Is this a new DEM?
Post by: Zaidín on June 14, 2014, 11:01:42 PM

"Dem1" resolution is 30 meters, but you get it directly to your phone...

In Spain we can get 5 meters resolution! free dems from National Geographic Institute (IGN).

Title: Re: Is this a new DEM?
Post by: mntr86 on June 16, 2014, 11:05:39 AM

Where can I find a high quality dem file for Italy?  I have downloaded the dem file from dem1 app but they are very bad.  I can't use it for altitude correction.



Thank you in advance



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Title: Re: Is this a new DEM?
Post by: febs on June 16, 2014, 01:26:45 PM

I just realized that the above picture has been resized by tapatalk, sorry about that. From here you can see it full size by clicking on it: //https://imgur.com/jcVcycT



And yeah, DEM1 files are the best we can get for Italy... yet. That is why I was asking about this new model.

Title: Re: Is this a new DEM?
Post by: febs on June 16, 2014, 01:35:43 PM

Mntr86... I just found this as well. I don't have the least idea about how to get any information out of it yet. Looks interesting though. Ciao :)



//http://www.pcn.minambiente.it/geoportal/catalog/search/resource/details.page?uuid={29D4257D-7130-4453-809F-3D39BC114694}

Title: Re: Is this a new DEM?
Post by: Zaidín on June 16, 2014, 02:47:07 PM

Here you can buy 20 meters resolution dems from italian army:

http://www.igmi.org/prodotti/dati_numerici/dati_matrix.php



DEMS are in ascii format, but you can converti it into hdr format using tools like Globalmapper and Compegpsland.

Title: Re: Is this a new DEM?
Post by: febs on June 16, 2014, 05:58:35 PM

Yeah it's the same DEM I linked above in WMS. The problem is that they are not good.



Unless, the version on sale and the WMS one are NOT the same data. I generated contour lines from that WMS and it quite sucked. The EU-DEM was SO much better!

Title: Re: Is this a new DEM?
Post by: Zaidín on June 16, 2014, 07:29:21 PM

The italian wms data you posted have a poor quality because are made from raster images. A software generates hillshading from contours lines of a physical map.   Real DEMs are based on aerial data from radar (planes or satellites).



In this italian forum comment this:

  http://www.mtb-forum.it/community/forum/showthread.php?t=179411

Title: Re: Is this a new DEM?
Post by: mntr86 on June 17, 2014, 09:04:47 AM

I have tried dem1 for altitude correction and it is very bad. I think that to obtain a good results needs a dem with resolution of 10 m minimum.



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Title: Re: Is this a new DEM?
Post by: mntr86 on June 17, 2014, 10:16:32 AM

There is a software for convert a dem file in ascii format to hgt for oruxmaps?



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