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| Norwegian DEM https://forum.transdem.de/viewtopic.php?f=7&t=630 |
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| Author: | pdw2107 [ 05 Feb 2022 13:59 ] |
| Post subject: | Re: Norwegian DEM |
Dear Roland, Thanks for doing so much to find out about this. I have tried with a slightly different download. When I try to unzip it into TransDem, TransDem says "Not a zip file with a SRTM DEM file in. etc". When I open the file with manual unzipping I get all the files in a catalogue, but TransDem will not open them. I will try with your settings... Peter |
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| Author: | geophil [ 06 Feb 2022 12:41 ] |
| Post subject: | Re: Norwegian DEM |
The original SRTM zips were something special, because their content was well-known. Any ordinary zip like ours here has to be unpacked manually. You should see several/a lot of tif "images" in them. But they aren't images. They are the DEMs. The format is TIFF, yes, but with additional georeferencing, so it's called GeoTIFF. TransDEM should open them if you set the file types to "all elevation data" in the Open File dialog. And make sure your downloads are complete. There may be a server overload problem. I also looked through my development logs and I found that the Norwegian site originally published the DEMs in a variant of the rather old USGS .dem format, which had been abandoned by the USGS before I started with TransDEM, but was still used by Canada until a few years ago. This format is not related to MicroDEM .dem, the standard format in TransDEM. TransDEM should support the Norwegian variant of the former USGS format, too, but I have not tested it now. Again, tif should work. |
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| Author: | pdw2107 [ 02 Feb 2024 17:40 ] |
| Post subject: | Re: Norwegian DEM |
Dear Roland, It’s a long time since I was last in touch with you. I have been trying to retrieve DEMS and raster maps from Høydedata (hoydedata.no) . I know you ,managed this from your previous mails on TransDem forum, but I have less success. I can just about get a DEM from this source, but have trouble with the raster maps. In TransDem it says it accepts tiff files, but the files I get from the Norwegian site seem to be a different format: it says they are GeoTIFF and seem to have a slightly different format from the TIFFs accepted by TransDem. Can you help me understand this? Many thanks for your help. Best wishes Peter Wood |
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| Author: | geophil [ 04 Feb 2024 11:31 ] |
| Post subject: | Re: Norwegian DEM |
Hi Peter, I understand, the Norwegian 1m DTMs in GeoTIFF format work for you? But I could not find any raster maps on the hoydedata.no site. Where did you get those from? The GeoTIFF specs offer many options and some providers make odd choices. Then it's hard to decode. |
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| Author: | pdw2107 [ 04 Feb 2024 13:24 ] |
| Post subject: | Re: Norwegian DEM |
geophil wrote: Hi Peter, I understand, the Norwegian 1m DTMs in GeoTIFF format work for you? But I could not find any raster maps on the hoydedata.no site. Where did you get those from? The GeoTIFF specs offer many options and some providers make odd choices. Then it's hard to decode. Hi Roland, You go to the Menu on the left, open it and choose English. Then you can go to "Display" on the right and open that. You can then choose either "Topopgrafisk norgeskart" eller or "Norge i bilder" , or others. I don't know which of these can be handled by TransDem? With "Topopgrafisk Norgeskart" I get a zip file, but when I try to open this in TransDem nothing happens. If I open the zip through Windows then I get a lot of files. I can get enough to put together a Dem of the area, but then I am missing maps to go with the Dem. I'm rather baffled! Greetings Peter |
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| Author: | geophil [ 07 Feb 2024 20:06 ] |
| Post subject: | Re: Norwegian DEM |
geophil wrote: You can then choose either "Topopgrafisk norgeskart" eller or "Norge i bilder" , or others. Peter, that will change the background map for the web page. How did you mange to download that? |
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| Author: | pdw2107 [ 09 Feb 2024 15:13 ] |
| Post subject: | Re: Norwegian DEM |
geophil wrote: geophil wrote: You can then choose either "Topopgrafisk norgeskart" eller or "Norge i bilder" , or others. Peter, that will change the background map for the web page. How did you mange to download that? Yes. There is an option to find different maps and they are on different websites. I can get the DEMS somehow by importing GeoTIFFS. But if I get the dems what is the next stage to get maps and import to Trainz? I have studied the manuals but get very confused.. Alternatively I could try the Web Mapping services though that looks even more complicated! Best wishes Peter |
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| Author: | geophil [ 11 Feb 2024 16:56 ] |
| Post subject: | Re: Norwegian DEM |
pdw2107 wrote: Alternatively I could try the Web Mapping services though that looks even more complicated! The easiest, fastest and most efficient way is Open Street Map, via the TransDEM Map Tile client. There is a tutorial for this in the manual, #7. You will see that it's not complicated at all.
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| Author: | pdw2107 [ 12 Feb 2024 21:09 ] |
| Post subject: | Re: Norwegian DEM |
geophil wrote: pdw2107 wrote: Alternatively I could try the Web Mapping services though that looks even more complicated! The easiest, fastest and most efficient way is Open Street Map, via the TransDEM Map Tile client. There is a tutorial for this in the manual, #7. You will see that it's not complicated at all.Yes, I might try that. However, I am trying another challenge first: I have managed to get maps from "Høydata" but they were PDF files and very good detail. I converted them to jpg. I have tried to Georeference the first one. I don't know what the national coordinating system is in Norway (I have asked them). According to the manual the map has to be set to this first? When I tried to start georeferencing I got to the dialogue box and put in the first SW corner point, east and west, but the "OK" button would not work. Do you know why this is? I assume the problem is not knowing the national coordinating system? I will try again when I have the answer from the "Høydata" web site. They are usually very helpful - also in English. Best wishes Peter |
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| Author: | pdw2107 [ 14 Feb 2024 11:43 ] |
| Post subject: | Re: Norwegian DEM |
Hi Roland When I asked about National Coordinating system for Norway, the answer from "Høydedata" is: "Do you mean the coordinates in the right, down corner of the screen? It`s in Euref89, sone 33." Does this help? I have reduced the resolution of the JPG to an acceptable level. What else can I do? Thanks for your help. Peter Wood |
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