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Way direction

It would be great if the generated ways would have consistent direction - eg higher elevation on right side of the way, so that the same xml can be used to render reliefs (with additional osmarender rules), not just contour lines. --Stefanb 09:47, 15 October 2007 (BST)

I'll try to fix that when I get on the task of debugging the isopletion algorithm. --Breki 13:22, 15 October 2007 (BST)
This is now fixed with the version 1.2 --Breki 07:00, 31 October 2007 (UTC)


CGIAR-CSI has void-filled SRTM data. Firefishy 15:51, 15 October 2007 (BST)

The original NASA data is in DTED (digital terrain elevation data) format, CGIAR has GeoTIFF and ArcInfo. When I find the time, I will try to extend the tool to be able to download and process data from at least one of those two formats. Thanks for the hint. --Breki 17:15, 15 October 2007 (BST)
I think that adding extra input types is unnecessary effort when users can simply use gdal_translate to turn GeoTIFF or ArcInfo into DTED. Or am I missing something?--Tms13 15:36, 21 January 2009 (UTC)

I would advise against considering the CGIAR-CSI data, since the license is incompatible with CC-BY-SA - the CGIAR has a non-commerical clause. Gravitystorm 15:21, 20 May 2008 (UTC)

If the choice of data source is a command-line option, then the user would be able to choose their source data based on their requirements. Whilst I naturally prefer free data, many of use would be able to make use of the maps with non-commercial restriction on them. Alternatively, the authors may be amenable to dual-licensing? --Tms13 12:16, 18 January 2009 (UTC)

not closed ways

I have tried latest version of your srtm2osm with command "Srtm2Osm.exe -bounds1 47 16 47.1 16.1", srtm.osm in JOSM shows that contour lines are not closed - seems like last "segment" of contour line is missing --Dido 15:10, 27 October 2007 (BST)

Yes, the algorithm for generating contour lines is somewhat buggy, it has some other problems, too. I am working on a complete rewrite of it, but I cannot say when it will be ready. Thanks for the notice. --Breki 20:15, 27 October 2007 (BST)
I tested the new 1.2 version with your area and now it looks OK. --Breki 06:59, 31 October 2007 (UTC)
much better, nice work.

Interpolation algorithm

I have one question: which method are you using for interpolation before finding contours ? I assume that method b) will produce finer contours in flat areas like lowlands. --Dido 09:48, 31 October 2007 (UTC) Srtm2osm methods.gif

Currently the method is simple, I just interpolate the elevation between the two nearest points with known elevation. Elevations in SRTM are rounded to 1 meter, and this presents a problem when you encounter an elevation which is exactly the elevation of the contour you are extracting (for example: 99 m in your diagram). I was looking for other possible contour extraction algorithms on Internet, but I couldn't find any.
BTW I'll be posting a new version of the tool later today with some additional bugfixes and options. --Breki 11:36, 31 October 2007 (UTC)

I'd recommend a curve-fitting interpolation such as bicubic - see Wikipedia article and this write-up. I don't know how you get from there to contours. Somewhere else to look for hints is at this UK project which produced nice maps but unfortunately only available in Garmin output (whilst Garmin is my main output format, I don't like their inclusion of very approximate sea tiles). He used DEM2Topo (sadly, a very restrictive license) and Blackart. --Tms13 12:12, 18 January 2009 (UTC)

Thanks for the links, I'll investigate this when I start working on Isohypse Binary File. I also plan to add contours support to GroundTruth (after the first version has been released, which should be soon). --Breki 16:31, 19 January 2009 (UTC)

Relation to DEM2TOPO

Can you elaborate a bit on the relation of Srtm@Osm and DEM2TOPO? They seem to work with the same data but I assume the output format is different? I ask this because I would like to be able to combine the DEM data with OSM data using a Linux machine. --Lambertus 22:18, 3 November 2007 (UTC)

What exactly do you mean by "related"? Yes, they are both using SRTM data and both can generate contours. Other than that they are not related: DEM2TOPO supports additional input formats. Srtm2Osm generates OSM output, DEM2TOPO generates shapefiles and polish format files. The tools were developed independently.
As for Linux support, I had reports that Srtm2Osm can be run on Linux under Wine, but I don't have any details. If this doesn't work, maybe you could convert DEM2TOPO shapefiles to OSM format? --Breki 06:54, 4 November 2007 (UTC)
I've had Srtm2Osm running on Ubuntu, using mono instead of Wine. I added a section to the main article named "Running On Linux" and put a few notes there. If I get time I'll work out which packages are needed and add more details. Avantman42 02:01, 9 December 2007 (UTC)
Thanks, any help is appreciated. --Breki 18:36, 9 December 2007 (UTC)

Convert HGT file manual

Is it possible to convert HGT files manual? There are better free HGT files on the net than those of NASA which I want to convert to OSM

By 'HGT' I assume you mean other types of DEM (digital elevation models)? Currently Srtm2Osm only supports SRTM3 data format, but I plan to extend it to also support SRTM1 and CGIAR-CSI datasets (see above). In theory, the tool should be able to process any raster digital elevation model, as long as it knows how to read it and where to put it geographically. --Breki 05:57, 7 November 2007 (UTC)

I mean to convert SRTM3 bij hand (commandline), like for example how MKGMAP converts OSM to the Garmin format. Now I can only download from the NASA site, and there are better free SRTM3 files on the net.--BertMu

If I understand correctly, you want to give the tool SRTM files yourself and not by downloading from the NASA FTP site. Currently this is not directly supported. The only way to achieve this would be to place your files into the SRTM cache directory, but the files would have to be in the same format as SRTM3 and have the same names and coordinates as the SRTM3 counterparts. The tool will then use your versions instead of downloading them from the server. I haven't tried it though. Can you give me an example (link) of these files you are talking about? --Breki 12:51, 7 November 2007 (UTC)

That is corect. Here is a link to a lot of information: --BertMu 20:16, 9 November 2007 (UTC)

Is it possible to use the data by Jonathan Ferranti? It's also .hgt but I believe SRTM1 instead of 3.

Allright I tried it out by placing them into SRTM Cache. It works very well. However it produces files of about 5 times the size. so -step 50 results in a size comparable to -step 10 when using the normal SRTM3 data. In mountaineous regions this means for mkgmap that you can only get about 0.1°*0.5° (for -step 10) into one maptile. The resulting quality is great however.--Extremecarver 14:38, 21 October 2008 (UTC)
Be careful when using tiles from that source, as far as I know the license is not compatibile with OSM's (see --Breki 20:21, 21 October 2008 (UTC)
Yes of course it can't be used on maps you intend to sell, but other than that for private use it's perfectly o.k. If need arises and someone want's to publish a map with this data I'm pretty sure Jonathan Ferranti would permit it (if credit to his work is given). The same goes for CGIAR. I think it should be possible for everyone to use that data privately together with OSM. Terms of Use:
Unless otherwise specified, images and data downloaded from this site may be reproduced for research and private use. 
Links to sources are preferred to the uploading of reproductions, but if that is not possible due to the need to change the size or format, 
then either an acknowledgement with a link to the appropriate source page, or my written permission, is demanded. Limited commercial use is OK, 
but anyone contemplating large scale reproduction should contact me. 
Specifically, the authorised use of the DEM data on this site for use in meshes uploaded or distributed for use in flight simulators is welcome, but this 
use of these data by anyone who neither (i) obtains my written permission nor (ii) properly credits me or my site, is not welcome and may be restrained.

--Extremecarver 22:37, 21 October 2008 (UTC)

Links: Perl version of srtm2osm

I have made an updated version of in the Perl version of srtm2osm, which will produce output which conforms to API 0.5. See

North of 60.25 deg N, there are no 3 second of arc SRTM data available. Coarser resolution 30 second data are available from a NASA FTP site in zipped binary form, and I have made a script to process these data in a form which will accept. See --alastairj 23:32, 5 January 2008 (UTC)

Thanks for doing that update, I don't have the ability to use .NET and the perl works just fine (so far). Only 'gotcha' was the hard coded 1000m ceiling, there are mountains ya know ;-) --Mungewell 15:52, 21 August 2008 (UTC)

Rendering using Osmarender

The code provided appears not to generate contours with osmarender version 6. If 's="way" ' is removed from the line

<rule e="way" s="way" k="contour" v="elevation">

then contours are generated and visible. --alastairj 22:37, 5 January 2008 (UTC)

Thanks. I haven't tried it with the osmarender 6, to be honest. I'm currently busy on another project (Kosmos) which is able to draw contours by itself. I'll remove the s="way" from the code in the article. --Breki 09:07, 6 January 2008 (UTC)

SRTM2OSM Source code

Hi Breki, is source code for SRTM2OSM available somewhere? I'd like to make some experimets with preprocessing of srtm hgt files --Dido 12:45, 6 January 2008 (UTC)

No, currently it's sitting on my local SVN server. I could release it to the public, but the problem is that it is a shared library which I use in Kosmos too and is currently going through some modifications (I'm working on a shaded relief implementation for Kosmos). So the only way would be to separate it completely, move it to the OSM SVN server and let it live its own life :). If you are really interested, send me a note. --Breki 18:25, 6 January 2008 (UTC)
Yes please, if my experiments ends with something useful, I will send changes back to you --Dido 11:47, 16 January 2008 (UTC)
Well, I think the best thing is for me to add the source code to the OSM SVN. I'll try to do this by the end of the week. --Breki 16:00, 16 January 2008 (UTC)

Option for naming output file

Currently the Srtm2Osm result file always is named 'srtm.osm'. For my Garmin map generation I would like to be able to rename this result file by providing a parameter (preferably determine the output path as well as it's name). This would allow me to e.g. run easily two instances of Srtm2Osm in parallel and also remove the need for moving and renaming the output file afterwards. --Lambertus 21:33, 13 March 2008 (UTC)

Are you sure? :)
-o <path>: specifies an output OSM file (default: 'srtm.osm')
--Breki 08:43, 15 March 2008 (UTC)
No, I'm not sure. The option is not mentioned on the article page so I assumed it wasn't there. Thanks for the heads-up! --Lambertus 14:43, 15 March 2008 (UTC)

Missing data?

In some places there seem to be missing data in the SRTM, e.g. here: I am pretty sure that the Zugspitze is not that flat ;-) Is this a problem of SRTM2OSM or the NASA data? R kleineisel 15:34, 7 August 2008 (UTC)

Please take a look at this: --Breki 18:57, 8 August 2008 (UTC)

"StartIndex" error

What can I do to solve the error below ?

g:\data\Srtm2Osm->Srtm2Osm.exe -bounds2 -25.778 28.29068 10 Srtm2Osm v1.4.25.1 by Igor Brejc

Uses SRTM data to generate elevation contour lines for use in OpenStreetMap

Connected to Current directory is srtm/version2/SRTM3 Current directory is Australia

ERROR: startIndex cannot be larger than length of string. Parameter name: startIndex

USAGE: Srtm2Osm <bounds> <options> ... -- Nic 17:15, 23 August 2008 (UTC)

It disappeared when I added -i -- Nic 22:27, 25 August 2008 (UTC)

SRTM2OSM + mkgmap tutorial?

Hi Breki, could you maybe write a brief tutorial/example on how to make a garmin topo map with srtm2topo and mkgmap? I am currently using the maps from, but they have elevations in feet, which I don't like at all. Winlemski 20:32, 5 September 2008 (UTC)

I have figured this out myself and written the article Topographic_maps_for_garmin_devices. Winlemski 20:41, 21 September 2008 (UTC)

OS Support

When will Srtm2Osm be available for other systems than Windows? Will any Mac or Linux ports be available in the near future? I only have access to windows at work, and with too many workers sharing a too slow line, downloading and generating typomaps at work is not accepted. --Skippern 16:30, 20 October 2008 (UTC)

Unfortunately I'm too busy with other stuff (Kosmos etc.), so I'm not planning any development work on Srtm2Osm. Anyway, the source code is in OSM SVN repository, so if anyone's interested, he/she can have a go at it. BTW as far as I know, Srtm2Osm works on Mono, so it should be available on Linux and Mac as it is. --Breki 18:10, 20 October 2008 (UTC)
I have successfully converted the whole world using Mono on a Kubuntu box --SlowRider 23:32, 15 November 2008 (UTC)

How can I map a country instead of deegrees?

Is there any way to take an osm file from Geofabrik (i.e. Austria) and only give out contourlines for the region covered inside that .osm file? I just tried rendering a rectangle around Austria

srtm2osm.exe -bounds1 46.320596 9.686142 48.999999 17.621614 -step 10 -cat 200 50 10 -large

This produced an img of 11.8GB, which is too big for me to continue processing. If I used -step 20 and only the area of Austria I'm sure that I would suceed in compiling an Garmin img with mkgmap without running out of memory... (it needed about 2 hours to calculate on a Pentium M with 2260MHz). edit: I'm just trying to compile the osm with mkgmap. It hasn't crashed since 10minutes alredy, might be working.... 11.8GB is however really insane.

Have a look at Topographic maps for garmin devices to see how you can create tiled topo maps. I do not think however that -step 10 is a good idea for the Alpes, the map will become quite cluttered --Winlemski 20:25, 23 October 2008 (UTC)
I figured out a bit compilicated way by now (trial and error till I found out how big tiles to create so that they still compile with mkgmap afterwards). Being able to use a bounding polygon would be great though. I think one could render first a box around a country, and then use osmosis to cout out the polygon. Afterwards one would then tile it down. (this will make up quite a long compile/make time, but should work). I like step 10 in general - the problem is rather that the SRTM3 is really inexact. Peaks are very flat or missing completely.....
The procedure you described (using osmosis) should give you the results you wanted. As for adding bounding polygon support to Srtm2Osm: I'm not actively developing Srtm2Osm anymore, so it will probably stay on the wish list (unless someone else wants to play around with the code, it's in the SVN). Anyway, I'd rather contribute some functionality that's not already available by other tools (meaning: osmosis is good enough for the job ;) ). --Breki 04:36, 24 October 2008 (UTC)

Limit the amount of nodes per heightline "way"

osm2navit has problems to convert some files created by srtm2osm into navit maps. The reason seems to be that some ways contain refs to to many nodes, so osm2navit, well, crashes :) . I filed a bug report here. While I agree that osm2navit could be fixed, maybe a future version of srtm2osm could split huge ways into multiple parts. osm2navit currently seems to accept a maximum of 24994 nodes, so maybe a maximum amount of 24,000 nodes or even less was a reasonable thing. BTW: mkgmap had no problems :) .

Problems while dowloading data


i tried to get some data, but i will not work for me. I hope you could help me.

I tried it with following command in windows command line:

D:\PRIVAT\OpenStreetMap\Programme\Topo>Srtm2Osm.exe -step 25 -cat 400 100 -large
-bounds1 47 8 48 9 -o 53273978.osm
Srtm2Osm v1.4.25.1 by Igor Brejc
Uses SRTM data to generate elevation contour lines for use in OpenStreetMap

I got no data, and for me it looks that nothing happens. I also tried it with a different SrtmIndex.dat for a user from germany. But no effect.

smrt folder is built, and after placing SrtmIndex.dat into smrt, the cache folder is built, but nothing else. I also deactivated all firewall.

Do you have any idea for me what i can do get data?


I also tried to connect to manual, i got a message that is connected, but after some seconds I get a message like "220#############################################" and then the connection is disconnected by server.

Best regards from Aschaffenburg, Germany. --Neucherl 08:56, 20 November 2008 (UTC)

Hi, I tried it with your command line and it works OK for me, it generates some 93 MB of OSM file. Maybe NASA's FTP site was down at the time you tried it, please try again. --Breki 20:32, 21 November 2008 (UTC)

Tried to use Srtm2Osm, but only got an error message (see below) - any ideas?

F:\Srtm2Osm>srtm2osm -bounds2 46.51 15.57 10

Srtm2Osm v1.4.25.1 by Igor Brejc

Uses SRTM data to generate elevation contour lines for use in OpenStreetMap

ERROR: No such host is known

Unhandled Exception: System.Net.Sockets.SocketException: No such host is known

  at System.Net.Dns.GetAddrInfo(String name)
  at System.Net.Dns.InternalGetHostByName(String hostName, Boolean includeIPv6)
  at System.Net.Dns.GetHostEntry(String hostNameOrAddress)
  at Brejc.DemLibrary.FtpClient.login() in d:\MyStuff\projects\OsmUtils\trunk\Brejc.DemLibrary\FtpClient.cs:line 211
  at Brejc.DemLibrary.SrtmIndex.Generate() in d:\MyStuff\projects\OsmUtils\trunk\Brejc.DemLibrary\SrtmIndex.cs:line 55
  at Srtm2Osm.Srtm2OsmCommand.Execute() in d:\MyStuff\projects\OsmUtils\trunk\Srtm2Osm\Srtm2OsmCommand.cs:line 59
  at Brejc.Common.Console.ConsoleApplicationBase.Run() in d:\MyStuff\BuildArea\Sandbox\Brejc.Common\trunk\Brejc.Common.Library\Console\ConsoleApplicationBase.cs:line 62
  at Srtm2Osm.Program.Main(String[] args) in d:\MyStuff\projects\OsmUtils\trunk\Srtm2Osm\Program.cs:line 12

Drbobo 10:54, 11 December 2008 (UTC)

Seems to relate to the (non-published) fact that srtm2osm does not support proxy servers... - right? Drbobo 15:26, 11 December 2008 (UTC)
You're right - no proxies, I'm afraid. But the source is published, so feel free to extend the code if you like. --Breki 19:11, 14 December 2008 (UTC)
The current version does support proxies. Srtm2Osm uses the global Windows / Linux proxy settings. See this guide for Windows; Linux users have to set the http_proxy environment variable. --Michi 02:01, 7 January 2012 (UTC)

I get a different error message, but only when trying to render a part of Sweden:

C:\Users\jochen\Documents\Karten\Composer>"C:\Program Files\Srtm2Osm-\Srtm2Osm.exe" -o C:\Users\jochen\Documents\Karten\Composer\Kanufahren_1_contour.osm -large -step 10 -cat 100 50 -bounds1 58.880001068115234 11.65999984741211 59.53200149536133 12.420000076293945 Srtm2Osm v1.4.25.1 by Igor Brejc

Uses SRTM data to generate elevation contour lines for use in OpenStreetMap

Connected to

ERROR: Failed to change directory.

Unbehandelte Ausnahme: System.IO.IOException: Failed to change directory.

  bei Brejc.DemLibrary.FtpClient.chdir(String dirName) in d:\MyStuff\projects\OsmUtils\trunk\Brejc.DemLibrary\FtpClient.cs:Zeile 624.
  bei Brejc.DemLibrary.FtpClient.login() in d:\MyStuff\projects\OsmUtils\trunk\

Brejc.DemLibrary\FtpClient.cs:Zeile 255.

  bei Brejc.DemLibrary.Srtm3Storage.LoadDemForArea(GeoBounds bounds) in d:\MyStuff\projects\OsmUtils\trunk\Brejc.DemLibrary\Srtm3Storage.cs:Zeile 113.
  bei Srtm2Osm.Srtm2OsmCommand.Execute() in d:\MyStuff\projects\OsmUtils\trunk\

Srtm2Osm\Srtm2OsmCommand.cs:Zeile 66.

  bei Brejc.Common.Console.ConsoleApplicationBase.Run() in d:\MyStuff\BuildArea\Sandbox\Brejc.Common\trunk\Brejc.Common.LibraryConsole\ConsoleApplicationBase.cs:Zeile 62.
  bei Srtm2Osm.Program.Main(String[] args) in d:\MyStuff\projects\OsmUtils\trunk\Srtm2Osm\Program.cs:Zeile 12.

Any idea what's going wrong here?

I get the same thing, appears to be down. --Davidfg4 03:55, 26 June 2009 (UTC)

Use boundary polygon instead of bounds

It would be much much better to be able to define a polygon placed inside a file instead of bounds consisting of 4 corners only! This would make it possible to save one step when generating garmin contourlines (and a lot of time). Currently I have to give the bounds option for 4 corners, and then run osmosis on the resulting file with the boundary polygon. Then split with osmosis into tiles, and finally run mkgmap on the output.

For Italy this means that the amount of data more than doubles when using srtm2osm instead of using a polygon defining the outskirts of italy, and with -20m interval one needs around 6GB of RAM to cut alongside the boundaries with osmosis (or run the computer overnight with a lot of swap space) Polygon Files for country boundaries can be e.g. downloaded from here (more or less correct): There is also a script called here on the wiki to extract boundaries from .osm files.

You are aware that this tool has been abandoned. It has been kept running during the recent server changes but it is unlikely that there will be any major feature development.
The feature you are proposing would be useful, of course. I am currently trying to do something similar with Composer. --Nop 12:40, 17 September 2009 (UTC)
I am aware of it. but 1.8 was also independant of breki. Maybe someone takes up the work, and above feature is IMHO the most important missing (from the list). Groundtruth is not working well at all for me. So only other try would be mkgmap directly and/or new tools.--Extremecarver 13:38, 17 September 2009 (UTC)
Contact Stefan Ungureanu, he worked on a tool to cut contours along polygon boundaries, but I don't know what the state of his tool is now --Breki 20:34, 18 October 2009 (UTC)

Merging data

ERROR: Exception of type 'System.OutOfMemoryException' was thrown

I got this error:

ERROR: Exception of type 'System.OutOfMemoryException' was thrown

I run srtm2osm on XP on command line: Srtm2Osm.exe -bounds1 47.2 5.8 55.2 15.1 -step 10 -cat 100 20 -large -corrxy 0.0005 0.0005 -o srtm.osm

After a while, i get this error!

>Srtm2Osm v1.8.14.10 by Igor Brejc > >Uses SRTM data to generate elevation contour lines for use in OpenStreetMap > >DEM data points count: 107156761 >DEM minimum elevation: -220 >DEM maximum elevation: 2937 >DEM has missing points: True > >ERROR: Exception of type 'System.OutOfMemoryException' was thrown.

What going wrong?


Your area 47.2 5.8 55.2 15.1 is too large for processing. Try splitting it in several smaller sections. --Nop 14:55, 23 March 2010 (UTC)
I tried it on another computer with XP. Without any problem. This computer has less RAM ( 1GByte instead of 2 GByte). It's an older AMD processer but without a proxy connection to internet. --Stepborc 21:15, 24 March 2010 (UTC)

Remote server returned an error

Hello. I hope it's OK to put help requests on this talk page. It's my first time using srtm2osm. I have it installed on my Debian Linux machine, using Mono, and I have also tried it on Windows, but I get the same error message on both:

ERROR: The remote server returned an error: (404) Not Found.
while accessing:

The command I'm using is (following the instructions in Topographic_maps_for_garmin_devices):

mono /opt/srtm2osm/Srtm2Osm.exe -step 25 -cat 400 100 -large -bounds1 40 0 4 1 1 -o 53272531.osm

I'm trying to download data for Spain. Can anybody point me in the right direction? Thanks a lot. Tongro 15:33, 15 April 2010 (UTC)

Which version of srtm2osm are you using? --Nop 16:46, 15 April 2010 (UTC)
Forgot that bit! It's Srtm2Osm- Tongro 17:14, 15 April 2010 (UTC)
Do you need a proy for web access? --Nop 14:31, 16 April 2010 (UTC)
Hmm ... it's working now. I'm certain my internet connection was OK at the time, but maybe I'm just going mad. Thanks for your interest. Tongro 18:17, 16 April 2010 (UTC)

Error using Mono/Linux, but OK on Windows

Hi. I've successfully created a map of part of Spain using srtm2osm with Mono/Linux, and now I'm trying to make one of the Canary Islands. When I run the following command:

mono /opt/srtm2osm/Srtm2Osm.exe -step 10 -cat 250 50 -large -bounds1 27 -17 28 -16 -o 53269458.osm

I get the following error each time:

ERROR: Error getting response stream (ReadDone2): ReceiveFailure
Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object
at Brejc.Common.Console.ConsoleApplicationBase.Run () [0x00000] 
at Srtm2Osm.Program.Main (System.String[] args) [0x00000]

The same command (without the mono bit) works with Windows. The tile in question is very simple, just a block of sea. I'm using Srtm2Osm and mono 1.9.1. Can anybody suggest a workaround? Thanks a lot. Tongro 13:34, 17 April 2010 (UTC)

Maybe you specified only -bounds as an option, without the number (should be -bounds1, 2 or 3). This simple mistake is not being caught. Navimont Feb 2011
Do you use a proxy server? I could reproduce this error once, but only if configured my debian to use a proxy server. --Michi 00:52, 5 December 2011 (UTC)
This bug (NullReferenceException) is fixed in the current 1.9 release. It was initially caused by problems on connecting to the server (ReceiveFailure). --Michi 00:23, 8 January 2012 (UTC)

ERROR: The requested feature is not implemented. (Ubuntu Linux & Mono)

Hi, I just stumbled on a possible bug. Can it be confirmed? I used the following command:

Srtm2Osm -large -step 5 -cat 50 25 -o 2340.srtm.osm -bounds1 48.999023 12.128906 49.614258 13.359375
Srtm2Osm v1.8.14.10 by Igor Brejc

Uses SRTM data to generate elevation contour lines for use in OpenStreetMap

DEM data points count: 1091503
DEM minimum elevation: 313
DEM maximum elevation: 1445
DEM has missing points: True
Analyzing elevation 310
Found segment with 4 vertices
Analyzing elevation 410
Found segment with 55 vertices

ERROR: The requested feature is not implemented.

I use Ubuntu Linux Lucid. The tile is from Germany. first time I see this. Must have touched something. Anyone able to repeat the error and possibly debug it?

--Remy 16:50, 14 May 2010 (UTC)

I can confirm this error with the latest version in SVN. User:Bomm also noticed this error, but it seems that neither he nor I do unterstand the code yet. ;-) --Michi 03:34, 4 December 2011 (UTC)

Nodes WITHOUT "lon" attribute

I used Srtm2Osm to render the contours of France (20/100/400 for minor, medium and major). But I've got a problem: many nodes don't have a "lon" attribute. This is for all nodes that should have a "lon=0" attribute. This is a problem, because I need to edit on the finished file to add it to work on this file with osmosis.

       <node id="2001434274" lat="44.872083333333336" lon="0.0010833333333334849" />
       <node id="2001434275" lat="44.87125" lon="0.00041666666666666669" />
       <node id="2001434276" lat="44.870416666666664" />
       <node id="2001434277" lat="44.869916666666668" lon="-0.00041666666666666669" />
       <node id="2001434278" lat="44.869583333333331" lon="-0.00097222222222247481" />

-- Lolo 32 15:32, 6 June 2011 (BST)

This bug is fixed in the current version (1.9), thanks for reporting. --Michi 00:24, 8 January 2012 (UTC)

Negative node id's after 2.147.483.647

Does Srtm2Osm use a signed 32bit integer as node id counter? If the file is big enough to reach node id #2.147.483.647, node id's turn negative after that (-2.147.483.648 and counting up towards 0). --Laufkaefer 12:22, 26 January 2012 (UTC)

Yes, all versions < 1.10 used 32 bit integers. This is fixed with version 1.10, which uses 64 bit integers. --Michi 02:54, 27 October 2012 (UTC)

Skip filesize check

Would it possible to skip the check for the filesize to enable srtm2osm to process hgt files generated from ASTER data (which were significantly larger at least with the conversion utility I used)? G0ldfish 12:25, 20 February 2012 (UTC)

Here (zip / sig) is a special version for you which does not check the filesize of the cells. --Michi 03:03, 27 October 2012 (UTC)

Fake contours when I used with -corrxy option

Srtm2Osm.exe -bounds1 37.95 138.2 38.0 138.3 -corrxy 0.0000 0.0000

made correct contours, but

Srtm2Osm.exe -bounds1 37.95 138.2 38.0 138.3 -corrxy 0.0005 0.0005

made wrong contours. There are fake contours on the north edge (lat=38.0).

So I use without corrxy option and replaced by perl script:

  if(m|^(.*<node .*)lat="([0-9\.\-]*)" lon="([0-9\.\-]*)"(.*)$|){
    printf ("%slat=\"%.14g\" lon=\"%.14g\"%s\n", $1, $2+0.0005, $3+0.0005, $4);
    print $_;

Using SRTM v3.0

I am wanted to use SRTM v3.0 (void-filled), but file layout on the web server is different with the one of v2.1. So, I modified source code and put here. Now, it seems worked well. --Mds878 (talk) 08:54, 7 December 2014 (UTC)

Tool for SRTM interpolation


I found that original SRTM data contains nasty errors in areas covered by snow (Alps). It is described here:

Here is one example (Pilatus mountain, near Luzern in Switzerland): https: (sorry for bad link, I don't see captcha for external links...)

Exists some open-source tool for interpolate these errors?