RE: [OSGeo-Discuss] 30m SRTM worldwide?
Hi Sylvain Great that you can deal with the anomalies in Grass.I hope that the note 'Undoubtedly the linear artifact are « step anomaly » (p. 19 text).' That should make the correction straightforward. I figured that by ink-stain they would imply some anomalous 'edge' like when a coffee-stains darkens at the edges. In any circumstance, you've got the upper hand on it now. .. and I've become fameous ;o) Carsten Hi Carsten, Continuing your idea I import ASTER QA Plain file ASTGTM_..._num.tiff in my GRASS location. It show a 1 to 3 stack count which borders areas superpose with artifacts (see both images end of http://yepca.org/wp3/?p=303 ). Next steep is to verify what append if I use the stack number to correct GDEM using GRASS mapcalc (something like 'if stack layer = 3 than GDEM =+20m'). Then comparing with SRTM-DEM in a untouched forest area... Let me dream... Thanks again Sylvain ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
Hi Carsten, Continuing your idea I import ASTER QA Plain file ASTGTM_..._num.tiff in my GRASS location. It show a 1 to 3 stack count which borders areas superpose with artifacts (see both images end of http://yepca.org/wp3/?p=303 ). Next steep is to verify what append if I use the stack number to correct GDEM using GRASS mapcalc (something like 'if stack layer = 3 than GDEM =+20m'). Then comparing with SRTM-DEM in a untouched forest area... Let me dream... Thanks again Sylvain 2011/8/27 Carsten Troelsgaard troelsgaard...@live.dk: Hi Sylvain The mystery moves to why they didn't 'fix' it in the first place. I noted that part of the Amazon Basin has a low overall stack-count. The QA file that follows the geoTiff-data is populated with data (stack-numbers) in the same format (geoTiff) .. that makes it possible to predict troubled areas. I'm not sure if your GIS-tools can incoorporate and use the auxillery-data. Carsten Sylvain wrote: Hi Carsten, It is almost certain that you are right. The chapter C. Residual Anomalies and Artifacts GDEM detailed Artifacts Related to Stack Number Irregular Boundaries. - Decripiton of the pits is similar to more or less circular holes I see. The text says they Regularity and Often Occur with high frequency in Virtually all ASTER GDEM tiles and from just a FEW meters to 100 meters or more. Ok - The large positive anomalies similar to mole run artifacts (p.23 of the text). - Undoubtedly the linear artifact are step anomaly (p. 19 text). Thank you for your comments, I'll put them on the blog to let things clear. Bests PS: as you assume, unfortunately, no amazon mystery reveled... Sylvain ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
RE: [OSGeo-Discuss] 30m SRTM worldwide?
Hi Sylvain The mystery moves to why they didn't 'fix' it in the first place.I noted that part of the Amazon Basin has a low overall stack-count.The QA file that follows the geoTiff-data is populated with data (stack-numbers) in the same format (geoTiff) .. that makes it possible to predict troubled areas. I'm not sure if your GIS-tools can incoorporate and use the auxillery-data. Carsten Sylvain wrote: Hi Carsten, It is almost certain that you are right. The chapter C. Residual Anomalies and Artifacts GDEM detailed Artifacts Related to Stack Number Irregular Boundaries. - Decripiton of the pits is similar to more or less circular holes I see. The text says they Regularity and Often Occur with high frequency in Virtually all ASTER GDEM tiles and from just a FEW meters to 100 meters or more. Ok - The large positive anomalies similar to mole run artifacts (p.23 of the text). - Undoubtedly the linear artifact are step anomaly (p. 19 text). Thank you for your comments, I'll put them on the blog to let things clear. Bests PS: as you assume, unfortunately, no amazon mystery reveled... Sylvain ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
RE : [OSGeo-Discuss] 30m SRTM worldwide?
Hi Carsten, I am afraid that this mystery relates to cost/available budget matters! Jean-Philippe De : discuss-boun...@lists.osgeo.org [discuss-boun...@lists.osgeo.org] de la part de Carsten Troelsgaard [troelsgaard...@live.dk] Date d'envoi : samedi 27 août 2011 09:55 À : lists.osgeo.org Objet : RE: [OSGeo-Discuss] 30m SRTM worldwide? Hi Sylvain The mystery moves to why they didn't 'fix' it in the first place. I noted that part of the Amazon Basin has a low overall stack-count. The QA file that follows the geoTiff-data is populated with data (stack-numbers) in the same format (geoTiff) .. that makes it possible to predict troubled areas. I'm not sure if your GIS-tools can incoorporate and use the auxillery-data. Carsten Sylvain wrote: Hi Carsten, It is almost certain that you are right. The chapter C. Residual Anomalies and Artifacts GDEM detailed Artifacts Related to Stack Number Irregular Boundaries. - Decripiton of the pits is similar to more or less circular holes I see. The text says they Regularity and Often Occur with high frequency in Virtually all ASTER GDEM tiles and from just a FEW meters to 100 meters or more. Ok - The large positive anomalies similar to mole run artifacts (p.23 of the text). - Undoubtedly the linear artifact are step anomaly (p. 19 text). Thank you for your comments, I'll put them on the blog to let things clear. Bests PS: as you assume, unfortunately, no amazon mystery reveled... Sylvain ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
Hi Carsten, It is almost certain that you are right. The chapter C. Residual Anomalies and Artifacts GDEM detailed Artifacts Related to Stack Number Irregular Boundaries. - Decripiton of the pits is similar to more or less circular holes I see. The text says they Regularity and Often Occur with high frequency in Virtually all ASTER GDEM tiles and from just a FEW meters to 100 meters or more. Ok - The large positive anomalies similar to mole run artifacts (p.23 of the text). - Undoubtedly the linear artifact are step anomaly (p. 19 text). Thank you for your comments, I'll put them on the blog to let things clear. Bests PS: as you assume, unfortunately, no amazon mystery reveled... Sylvain 2011/8/26 Carsten Troelsgaard troelsgaard...@live.dk I looked around for information about the artefacts in the aster data. The Quality Assessment file that accompanies the data mentions: Quote The automated cloud masking and statistical approach used to select data for stacking are not totally effective in avoiding anomalous elevations values, and anomalies may remain in the GDEM where the stack number is three or less, particularly. Where available, existing DEMs were used to replace anomalous GDEM values, including adjusting for offsets between the ASTER GDEM and the reference DEM data. UnQuote following the link: http://www.ersdac.or.jp/GDEM/E/image/ASTERGDEM_ValidationSummaryReport_Ver1.pdf At page ~20 the chapter Artifacts Related to Irregular Stack Number Boundaries. has additional information and visual displays equal to the ones you link to at //yepka.. It would be interesting if the artefacts reveal some secret about the landscape, but so far I've treated as a measurement/processing-error. I assume that 'stack-number' originates from overlapping measurement-swats Carsten Sylv wrote: I used a re-sampling to 30m of SRTM-DEM (made by Brazilian INPE) and observe a visual superposition between GRASS-r.watershed river network output and 2001 Landsat7 deforested areas (the nearest date after SRTM) (see http://yepca.org/wp3/?p=349) As you suggest, I'll verify if CGIAR SRTM-DEM is better in such flat area with forest/cultivation patchwork. In first analyze, ASTER GDEM gave better river network, even with the theses 20-30m holes or larges areas artifacts!... but more job is necessary to verify and understand why! Sylv ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
+1 We conducted our own site specific comparison and we concluded that SRTM is much better especially those post-processed by CGIAR. Depending on where you are there are issues with ASTER GDEM: http://gis.cri.fmach.it/aster-gdem-quality/ Markus Or in flat tropical area... http://yepca.org/wp3/?p=303 Thanks! Shared and bookmarked this site! -- cheers, maning -- Freedom is still the most radical idea of all -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ -- ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
I used a re-sampling to 30m of SRTM-DEM (made by Brazilian INPE) and observe a visual superposition between GRASS-r.watershed river network output and 2001 Landsat7 deforested areas (the nearest date after SRTM) (see http://yepca.org/wp3/?p=349) As you suggest, I'll verify if CGIAR SRTM-DEM is better in such flat area with forest/cultivation patchwork. In first analyze, ASTER GDEM gave better river network, even with the theses 20-30m holes or larges areas artifacts!... but more job is necessary to verify and understand why! Sylv 2011/8/24 maning sambale emmanuel.samb...@gmail.com +1 We conducted our own site specific comparison and we concluded that SRTM is much better especially those post-processed by CGIAR. Depending on where you are there are issues with ASTER GDEM: http://gis.cri.fmach.it/aster-gdem-quality/ Markus Or in flat tropical area... http://yepca.org/wp3/?p=303 Thanks! Shared and bookmarked this site! -- cheers, maning -- Freedom is still the most radical idea of all -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ -- ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
2011/8/22 Markus Neteler nete...@osgeo.org On Mon, Aug 22, 2011 at 3:32 PM, Seb sebhud...@gmail.com wrote: Hi, The Aster DEM has 30m posting and covers most of the globe. http://free-gis-data.blogspot.com/2009/04/aster-global-digital-elevation-model.html Depending on where you are there are issues with ASTER GDEM: http://gis.cri.fmach.it/aster-gdem-quality/ Markus Or in flat tropical area... http://yepca.org/wp3/?p=303 Sylv ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
[OSGeo-Discuss] 30m SRTM worldwide?
I got this news recently, from this website, one can download ~30m SRTM data: http://eoweb.dlr.de:8080/index.html The X-band SRTM DEM data are provided in DTED format. Detailed information on the DTED format can be found in the document 'Product Description of the SRTM DTED-Format' (SRTM/PD-03/11/03) available at http://www.dlr.de/srtm/docs/SRTM-XSAR-DEM-DTED-1.1.pdf. The DEM and HEM data are in geographic (Lat/Long) projection, datum WGS84. The elevation values are also WGS84, as specified in the product description of the SRTM DTED-format. The DEMs inside the compressed archive are distributed as individual files, i.e. they are not mosaicked into one large DEM file. Each DEM covers an area of 15' by 15'. The filename of the individual DEM file specifies the bottom left coordinate of the corresponding 15' by 15' DEM tile. One pixel of the DEM files corresponds to approximately 25 m x 25 m on the ground. The elevation values are provided at a resolution of 1 m. The horizontal accuracy of the SRTM X-band DEMs is ±20 m (abs.) / ±15 m (rel.), both 90% CE. The vertical accuracy is ±16 m (abs.) / ±6 m (rel.), both 90% LE. Precise information on vertical and horizontal accuracies for individual tiles can be found in the accuracy description record (ACC) of the DTED file. I tried to access the public portal, but I just got the Loading java virtual machine message. Anyone here, who can access the data and is it really available to the public? -- cheers, maning -- Freedom is still the most radical idea of all -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ -- ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
Hi, you can also download them from the earthexplorer ui from the USGS ( http://earthexplorer.usgs.gov) more informations on http://eros.usgs.gov/#/Find_Data/Products_and_Data_Available/SRTM cheers, Sylvain 2011/8/22 maning sambale emmanuel.samb...@gmail.com I got this news recently, from this website, one can download ~30m SRTM data: http://eoweb.dlr.de:8080/index.html The X-band SRTM DEM data are provided in DTED format. Detailed information on the DTED format can be found in the document 'Product Description of the SRTM DTED-Format' (SRTM/PD-03/11/03) available at http://www.dlr.de/srtm/docs/SRTM-XSAR-DEM-DTED-1.1.pdf. The DEM and HEM data are in geographic (Lat/Long) projection, datum WGS84. The elevation values are also WGS84, as specified in the product description of the SRTM DTED-format. The DEMs inside the compressed archive are distributed as individual files, i.e. they are not mosaicked into one large DEM file. Each DEM covers an area of 15' by 15'. The filename of the individual DEM file specifies the bottom left coordinate of the corresponding 15' by 15' DEM tile. One pixel of the DEM files corresponds to approximately 25 m x 25 m on the ground. The elevation values are provided at a resolution of 1 m. The horizontal accuracy of the SRTM X-band DEMs is ±20 m (abs.) / ±15 m (rel.), both 90% CE. The vertical accuracy is ±16 m (abs.) / ±6 m (rel.), both 90% LE. Precise information on vertical and horizontal accuracies for individual tiles can be found in the accuracy description record (ACC) of the DTED file. I tried to access the public portal, but I just got the Loading java virtual machine message. Anyone here, who can access the data and is it really available to the public? -- cheers, maning -- Freedom is still the most radical idea of all -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ -- ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
Hi, Try this site, they have lots of other data available as well. http://glcf.umd.edu/data/ or more specifically http://glcf.umd.edu/data/srtm/. They all also have an interactive map, though a bit fiddly to select and download data from. HTH Cheers Seb On 22 August 2011 09:48, maning sambale emmanuel.samb...@gmail.com wrote: I got this news recently, from this website, one can download ~30m SRTM data: http://eoweb.dlr.de:8080/index.html The X-band SRTM DEM data are provided in DTED format. Detailed information on the DTED format can be found in the document 'Product Description of the SRTM DTED-Format' (SRTM/PD-03/11/03) available at http://www.dlr.de/srtm/docs/SRTM-XSAR-DEM-DTED-1.1.pdf. The DEM and HEM data are in geographic (Lat/Long) projection, datum WGS84. The elevation values are also WGS84, as specified in the product description of the SRTM DTED-format. The DEMs inside the compressed archive are distributed as individual files, i.e. they are not mosaicked into one large DEM file. Each DEM covers an area of 15' by 15'. The filename of the individual DEM file specifies the bottom left coordinate of the corresponding 15' by 15' DEM tile. One pixel of the DEM files corresponds to approximately 25 m x 25 m on the ground. The elevation values are provided at a resolution of 1 m. The horizontal accuracy of the SRTM X-band DEMs is ±20 m (abs.) / ±15 m (rel.), both 90% CE. The vertical accuracy is ±16 m (abs.) / ±6 m (rel.), both 90% LE. Precise information on vertical and horizontal accuracies for individual tiles can be found in the accuracy description record (ACC) of the DTED file. I tried to access the public portal, but I just got the Loading java virtual machine message. Anyone here, who can access the data and is it really available to the public? -- cheers, maning -- Freedom is still the most radical idea of all -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ -- ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss -- Seb Hudson +44 (0) 1970 625368 +44 (0) 7811 268789 ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
Dear Sylvain, The USGS site, provides ~30m SRTM only for the US. I'm looking the 30m worldwide coverage. That was mentioned in the link I provided. On Mon, Aug 22, 2011 at 4:59 PM, Sylvain Maillard sylvain.maill...@gmail.com wrote: Hi, you can also download them from the earthexplorer ui from the USGS (http://earthexplorer.usgs.gov) more informations on http://eros.usgs.gov/#/Find_Data/Products_and_Data_Available/SRTM cheers, Sylvain 2011/8/22 maning sambale emmanuel.samb...@gmail.com I got this news recently, from this website, one can download ~30m SRTM data: http://eoweb.dlr.de:8080/index.html The X-band SRTM DEM data are provided in DTED format. Detailed information on the DTED format can be found in the document 'Product Description of the SRTM DTED-Format' (SRTM/PD-03/11/03) available at http://www.dlr.de/srtm/docs/SRTM-XSAR-DEM-DTED-1.1.pdf. The DEM and HEM data are in geographic (Lat/Long) projection, datum WGS84. The elevation values are also WGS84, as specified in the product description of the SRTM DTED-format. The DEMs inside the compressed archive are distributed as individual files, i.e. they are not mosaicked into one large DEM file. Each DEM covers an area of 15' by 15'. The filename of the individual DEM file specifies the bottom left coordinate of the corresponding 15' by 15' DEM tile. One pixel of the DEM files corresponds to approximately 25 m x 25 m on the ground. The elevation values are provided at a resolution of 1 m. The horizontal accuracy of the SRTM X-band DEMs is ±20 m (abs.) / ±15 m (rel.), both 90% CE. The vertical accuracy is ±16 m (abs.) / ±6 m (rel.), both 90% LE. Precise information on vertical and horizontal accuracies for individual tiles can be found in the accuracy description record (ACC) of the DTED file. I tried to access the public portal, but I just got the Loading java virtual machine message. Anyone here, who can access the data and is it really available to the public? -- cheers, maning -- Freedom is still the most radical idea of all -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ -- ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss -- cheers, maning -- Freedom is still the most radical idea of all -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ -- ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
Hi everyone, I can create a transparent overlay for Garmin Map (IMG files), of the entire planet for these SRTM contour lines. I can use the grid of .1x.1degree tiles. If their is any use for having this map, on a global-scale, please let me know, i i can create it. I could also upload this data in the .osm file format to the commonmap development API, so then it can be downloads easily. if there is a demand, an API can be created to host this specifically. Thanks, Sam On 8/22/11, maning sambale emmanuel.samb...@gmail.com wrote: Dear Sylvain, The USGS site, provides ~30m SRTM only for the US. I'm looking the 30m worldwide coverage. That was mentioned in the link I provided. On Mon, Aug 22, 2011 at 4:59 PM, Sylvain Maillard sylvain.maill...@gmail.com wrote: Hi, you can also download them from the earthexplorer ui from the USGS (http://earthexplorer.usgs.gov) more informations on http://eros.usgs.gov/#/Find_Data/Products_and_Data_Available/SRTM cheers, Sylvain 2011/8/22 maning sambale emmanuel.samb...@gmail.com I got this news recently, from this website, one can download ~30m SRTM data: http://eoweb.dlr.de:8080/index.html The X-band SRTM DEM data are provided in DTED format. Detailed information on the DTED format can be found in the document 'Product Description of the SRTM DTED-Format' (SRTM/PD-03/11/03) available at http://www.dlr.de/srtm/docs/SRTM-XSAR-DEM-DTED-1.1.pdf. The DEM and HEM data are in geographic (Lat/Long) projection, datum WGS84. The elevation values are also WGS84, as specified in the product description of the SRTM DTED-format. The DEMs inside the compressed archive are distributed as individual files, i.e. they are not mosaicked into one large DEM file. Each DEM covers an area of 15' by 15'. The filename of the individual DEM file specifies the bottom left coordinate of the corresponding 15' by 15' DEM tile. One pixel of the DEM files corresponds to approximately 25 m x 25 m on the ground. The elevation values are provided at a resolution of 1 m. The horizontal accuracy of the SRTM X-band DEMs is ±20 m (abs.) / ±15 m (rel.), both 90% CE. The vertical accuracy is ±16 m (abs.) / ±6 m (rel.), both 90% LE. Precise information on vertical and horizontal accuracies for individual tiles can be found in the accuracy description record (ACC) of the DTED file. I tried to access the public portal, but I just got the Loading java virtual machine message. Anyone here, who can access the data and is it really available to the public? -- cheers, maning -- Freedom is still the most radical idea of all -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ -- ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss -- cheers, maning -- Freedom is still the most radical idea of all -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ -- ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss -- --- Across Canada Trails - Beyond 2017 - The National Trails Network Victoria, BC Canada Twitter: @Acrosscanada Blog: http://acrosscanadatrails.posterous.com/ Facebook: http://www.facebook.com/sam.vekemans Skype: 'Sam Vekemans' Member, CommonMap Inc. http://commonmap.org/ IRC: irc://irc.oftc.net #CommonMap Also find us on Facebook, Twitter and LinkedIn ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
2011/8/22 maning sambale emmanuel.samb...@gmail.com Dear Sylvain, The USGS site, provides ~30m SRTM only for the US. I'm looking the 30m worldwide coverage. That was mentioned in the link I provided. In fact the SRTM data is available at 1 arc-second for the US, but there is only 3 arc-second data fot the global coverage ! see http://eros.usgs.gov/Find_Data/Products_and_Data_Available/SRTM on section SRTM Data regards, Sylvain ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
You could try here http://www.opentopography.org/index.php/blog/detail/comparison_of_aster_gdem_to_srtm On 22 August 2011 10:22, Sylvain Maillard sylvain.maill...@gmail.comwrote: 2011/8/22 maning sambale emmanuel.samb...@gmail.com Dear Sylvain, The USGS site, provides ~30m SRTM only for the US. I'm looking the 30m worldwide coverage. That was mentioned in the link I provided. In fact the SRTM data is available at 1 arc-second for the US, but there is only 3 arc-second data fot the global coverage ! see http://eros.usgs.gov/Find_Data/Products_and_Data_Available/SRTM on section SRTM Data regards, Sylvain ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss -- Seb Hudson +44 (0) 1970 625368 +44 (0) 7811 268789 ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
RE: [OSGeo-Discuss] 30m SRTM worldwide?
hi seb and sembale The link provides two links:NASA’s EOS archive or Japan’s Ground Data System both probably contains the data, but it's a lousy quality and not worth the download .. and the registration at EOS is rather strict The best DEM I've got is 90m via http://srtm.csi.cgiar.org/ and their server is overworked and won't let you take more than a couple of tiles.There's a few 30m tiles at http://www.viewfinderpanoramas.org/if memory serves me right CarstenDate: Mon, 22 Aug 2011 10:25:53 +0100 Subject: Re: [OSGeo-Discuss] 30m SRTM worldwide? From: sebhud...@gmail.com To: discuss@lists.osgeo.org You could try here http://www.opentopography.org/index.php/blog/detail/comparison_of_aster_gdem_to_srtm On 22 August 2011 10:22, Sylvain Maillard sylvain.maill...@gmail.com wrote: 2011/8/22 maning sambale emmanuel.samb...@gmail.com Dear Sylvain, The USGS site, provides ~30m SRTM only for the US. I'm looking the 30m worldwide coverage. That was mentioned in the link I provided. In fact the SRTM data is available at 1 arc-second for the US, but there is only 3 arc-second data fot the global coverage ! see http://eros.usgs.gov/Find_Data/Products_and_Data_Available/SRTM on section SRTM Data regards, Sylvain ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss -- Seb Hudson +44 (0) 1970 625368 +44 (0) 7811 268789 ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
Hi, The Aster DEM has 30m posting and covers most of the globe. http://free-gis-data.blogspot.com/2009/04/aster-global-digital-elevation-model.html Also http://www.terrainmap.com/rm22.html However, as I understand it, the the most recent version of the STRM, despite a 90m grid, may give you better details especially on flatter areas with greater cloud cover than the ASTER withs its 30m posting. The ASTER may have the edge in areas of sharper relief. I can try dig out the technical reasons if you like. We've downloaded large amounts of both with not too much hassle. HTH Seb Cheers Seb On 22 August 2011 12:11, Carsten Troelsgaard troelsgaard...@live.dk wrote: hi seb and sembale The link provides two links: NASA’s EOS archive http://asterweb.jpl.nasa.gov/gdem-wist.asp or Japan’s Ground Data System http://www.gdem.aster.ersdac.or.jp/index.jsp both probably contains the data, but it's a lousy quality and not worth the download .. and the registration at EOS is rather strict The best DEM I've got is 90m via http://srtm.csi.cgiar.org/ and their server is overworked and won't let you take more than a couple of tiles. There's a few 30m tiles at http://www.viewfinderpanoramas.org/ if memory serves me right Carsten -- Date: Mon, 22 Aug 2011 10:25:53 +0100 Subject: Re: [OSGeo-Discuss] 30m SRTM worldwide? From: sebhud...@gmail.com To: discuss@lists.osgeo.org You could try here http://www.opentopography.org/index.php/blog/detail/comparison_of_aster_gdem_to_srtm On 22 August 2011 10:22, Sylvain Maillard sylvain.maill...@gmail.comwrote: 2011/8/22 maning sambale emmanuel.samb...@gmail.com Dear Sylvain, The USGS site, provides ~30m SRTM only for the US. I'm looking the 30m worldwide coverage. That was mentioned in the link I provided. In fact the SRTM data is available at 1 arc-second for the US, but there is only 3 arc-second data fot the global coverage ! see http://eros.usgs.gov/Find_Data/Products_and_Data_Available/SRTM on section SRTM Data regards, Sylvain ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss -- Seb Hudson +44 (0) 1970 625368 +44 (0) 7811 268789 ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss -- Seb Hudson +44 (0) 1970 625368 +44 (0) 7811 268789 ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] 30m SRTM worldwide?
On Mon, Aug 22, 2011 at 3:32 PM, Seb sebhud...@gmail.com wrote: Hi, The Aster DEM has 30m posting and covers most of the globe. http://free-gis-data.blogspot.com/2009/04/aster-global-digital-elevation-model.html Depending on where you are there are issues with ASTER GDEM: http://gis.cri.fmach.it/aster-gdem-quality/ Markus ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
RE: [OSGeo-Discuss] 30m SRTM worldwide?
Hi Seb I've never been there and look forward to tryif anyone should have become interested in a flyby in these data, my previously mentioned tiff/hgt-viewer is still available athttps://skydrive.live.com/?cid=382e99b169b58267#cid=382E99B169B58267id=382E99B169B58267%21194(press F to get a FileOpen-prompt) .. any feedback is welcome.I hope the aside doesn't bother you Sep. Carsten - Seb wrote: The Aster DEM has 30m posting and covers most of the globe. http://free-gis-data.blogspot.com/2009/04/aster-global-digital-elevation-model.html Also ... ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
