Re: [GRASS-user] shapefile, TIGER, or what for a dlg that is stored in .e00 format
On Wed, Jul 8, 2009 at 10:17 PM, Hamish wrote: > >> stephen sefick wrote: >> > I am trying to make a DEM from contour lines downloaded from here >> > http://csat.er.usgs.gov/statewide/layers/contours.html > > fwiw, v.in.ogr's SDTS driver might help to import DLGs more directly. > ?? > > > Nikos wrote: >> Perhaps you do not even need to rasterise. Have a look at v.surf.rst >> [2]. Of course I am no expert with DEM's, v.surf.rst might not be what >> you need. > > v.surf.rst does not do all that well with contour lines. due to the > adaptive grid size / quadtree design it focuses detail on where the data > points are. In this case that's the vertices along the contour lines. > > r.surf.contour does a nice job with them though, just read in the help > page about overcoming the lack of floating-point support, if that is > needed. > > > also, as mentioned there is probably a higher resolution DEM already out > there for free, e.g. SRTM 1" (~30m) resolution or USGS quads. Right. On the seamless.usgs.gov server you should be able to get the most recent 10m resolution DEM for free in GeoTiff or Arc Grid format. Cheers, Dylan ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] shapefile, TIGER, or what for a dlg that is stored in .e00 format
stephen sefick wrote: > I tried this with points, lines and areas on the .e00 file > > v.in.e00 'file=/Users/sefick/Desktop/contours Folder/contours.e00' \ > type=area vect=georgia_contours --overwrite > > importing areas.. > > unable to open data an error occured. Stop. that was a bug in the script, it failed because of the space in the path name. Now fixed in SVN. Either update to latest SVN or rename the folder so it doesn't have any spaces in it. Hamish ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] shapefile, TIGER, or what for a dlg that is stored in .e00 format
> stephen sefick wrote: > > I am trying to make a DEM from contour lines downloaded from here > > http://csat.er.usgs.gov/statewide/layers/contours.html fwiw, v.in.ogr's SDTS driver might help to import DLGs more directly. ?? Nikos wrote: > Perhaps you do not even need to rasterise. Have a look at v.surf.rst > [2]. Of course I am no expert with DEM's, v.surf.rst might not be what > you need. v.surf.rst does not do all that well with contour lines. due to the adaptive grid size / quadtree design it focuses detail on where the data points are. In this case that's the vertices along the contour lines. r.surf.contour does a nice job with them though, just read in the help page about overcoming the lack of floating-point support, if that is needed. also, as mentioned there is probably a higher resolution DEM already out there for free, e.g. SRTM 1" (~30m) resolution or USGS quads. Hamish ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] shapefile, TIGER, or what for a dlg that is stored in .e00 format
Hi, Do you need to use this data for the generation of a DEM? Would it be possible to use another source? seamless.usgs.gov is a great place to get gridded elevation data for the USA. Interpolating from contours should be a last resort. Cheers, Dylan On Wed, Jul 8, 2009 at 6:42 PM, stephen sefick wrote: > I tried this with points, lines and areas on the .e00 file > > v.in.e00 'file=/Users/sefick/Desktop/contours Folder/contours.e00' > type=area vect=georgia_contours --overwrite > > importing areas.. > > unable to open data > an error occured. Stop. > > what now? > > I didn't have any luck with the grid data - tried and gave up. > > thanks > > Stephen Sefick > > On Wed, Jul 8, 2009 at 7:38 PM, Nikos > Alexandris wrote: >> >> stephen sefick wrote: >> >>> I am trying to make a DEM from contour lines downloaded from here >>> http://csat.er.usgs.gov/statewide/layers/contours.html >>> I converted this to a shape file >> >> You don't need to convert it to Shapefile. You can import vector .e00 >> files directly in GRASS using v.in.e00. Note that you need to have to >> programs installed: "avce00" and "e00compr". >> >> >>> reprojected it, >> >> why? from what to what CRS? Did you not create a location based on the >> coordinate reference system in which the data are referenced? Did you >> have any success with the "GRID" data, if of course you tried? >> >> >>> and then v.to.rast use=value and got out a raster with a range of 1 >>> to 1. >> >> That is so because the v.to.rast module expects from the user to define >> the "value" incase you use the "use=value" parameter. If the user does >> not define the "value" then "value=1" is taken as default. Please read >> the respective manual(s) [1]. >> >> I suppose that "v.to.rast use=val value=SomeValue" is not what you want. >> Giving a fixed value to all of the vector features that will be >> rasterized wont be useful if you want to play further with the data >> (e.g. create a DEM as you mention above). >> >> >>> How do I do this? >> >> --%<---code--%<--- >> # I downloaed the data you mention and did the following: >> v.in.e00 contours.e00 vect=contours type=line >> >> # check attribute table >> v.info -c contours >> >> v.info -c contours >> Displaying column types/names for database connection of layer 1: >> INTEGER|cat >> INTEGER|UserId >> INTEGER|FNODE_ >> INTEGER|TNODE_ >> INTEGER|LPOLY_ >> INTEGER|RPOLY_ >> DOUBLE PRECISION|LENGTH >> INTEGER|CONTOURS_ >> INTEGER|CONTOURS_I >> INTEGER|ELEV >> >> # match region ## I am unsure about the resolution (=look at the >> original data resolution from which the contours derived) >> g.region vect=contours res=SomeResolutionValue -pa >> >> # the last column is probably of your interest, so >> v.to.rast use=val value=attr col=ELEV >> --%<---code--%<--- >> >> Perhaps you do not even need to rasterise. Have a look at v.surf.rst >> [2]. Of course I am no expert with DEM's, v.surf.rst might not be what >> you need. >> >> Kind regards, Nikos >> --- >> >> [1] http://grass.osgeo.org/grass64/manuals/html64_user/v.to.rast.html >> >> [2] http://grass.osgeo.org/grass64/manuals/html64_user/v.surf.rst.html >> >> > > > > -- > Stephen Sefick > > Let's not spend our time and resources thinking about things that are > so little or so large that all they really do for us is puff us up and > make us feel like gods. We are mammals, and have not exhausted the > annoying little problems of being mammals. > > -K. Mullis > ___ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user > ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] shapefile, TIGER, or what for a dlg that is stored in .e00 format
I tried this with points, lines and areas on the .e00 file v.in.e00 'file=/Users/sefick/Desktop/contours Folder/contours.e00' type=area vect=georgia_contours --overwrite importing areas.. unable to open data an error occured. Stop. what now? I didn't have any luck with the grid data - tried and gave up. thanks Stephen Sefick On Wed, Jul 8, 2009 at 7:38 PM, Nikos Alexandris wrote: > > stephen sefick wrote: > >> I am trying to make a DEM from contour lines downloaded from here >> http://csat.er.usgs.gov/statewide/layers/contours.html >> I converted this to a shape file > > You don't need to convert it to Shapefile. You can import vector .e00 > files directly in GRASS using v.in.e00. Note that you need to have to > programs installed: "avce00" and "e00compr". > > >> reprojected it, > > why? from what to what CRS? Did you not create a location based on the > coordinate reference system in which the data are referenced? Did you > have any success with the "GRID" data, if of course you tried? > > >> and then v.to.rast use=value and got out a raster with a range of 1 >> to 1. > > That is so because the v.to.rast module expects from the user to define > the "value" incase you use the "use=value" parameter. If the user does > not define the "value" then "value=1" is taken as default. Please read > the respective manual(s) [1]. > > I suppose that "v.to.rast use=val value=SomeValue" is not what you want. > Giving a fixed value to all of the vector features that will be > rasterized wont be useful if you want to play further with the data > (e.g. create a DEM as you mention above). > > >> How do I do this? > > --%<---code--%<--- > # I downloaed the data you mention and did the following: > v.in.e00 contours.e00 vect=contours type=line > > # check attribute table > v.info -c contours > > v.info -c contours > Displaying column types/names for database connection of layer 1: > INTEGER|cat > INTEGER|UserId > INTEGER|FNODE_ > INTEGER|TNODE_ > INTEGER|LPOLY_ > INTEGER|RPOLY_ > DOUBLE PRECISION|LENGTH > INTEGER|CONTOURS_ > INTEGER|CONTOURS_I > INTEGER|ELEV > > # match region ## I am unsure about the resolution (=look at the > original data resolution from which the contours derived) > g.region vect=contours res=SomeResolutionValue -pa > > # the last column is probably of your interest, so > v.to.rast use=val value=attr col=ELEV > --%<---code--%<--- > > Perhaps you do not even need to rasterise. Have a look at v.surf.rst > [2]. Of course I am no expert with DEM's, v.surf.rst might not be what > you need. > > Kind regards, Nikos > --- > > [1] http://grass.osgeo.org/grass64/manuals/html64_user/v.to.rast.html > > [2] http://grass.osgeo.org/grass64/manuals/html64_user/v.surf.rst.html > > -- Stephen Sefick Let's not spend our time and resources thinking about things that are so little or so large that all they really do for us is puff us up and make us feel like gods. We are mammals, and have not exhausted the annoying little problems of being mammals. -K. Mullis ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] shapefile, TIGER, or what for a dlg that is stored in .e00 format
stephen sefick wrote: > I am trying to make a DEM from contour lines downloaded from here > http://csat.er.usgs.gov/statewide/layers/contours.html > I converted this to a shape file You don't need to convert it to Shapefile. You can import vector .e00 files directly in GRASS using v.in.e00. Note that you need to have to programs installed: "avce00" and "e00compr". > reprojected it, why? from what to what CRS? Did you not create a location based on the coordinate reference system in which the data are referenced? Did you have any success with the "GRID" data, if of course you tried? > and then v.to.rast use=value and got out a raster with a range of 1 > to 1. That is so because the v.to.rast module expects from the user to define the "value" incase you use the "use=value" parameter. If the user does not define the "value" then "value=1" is taken as default. Please read the respective manual(s) [1]. I suppose that "v.to.rast use=val value=SomeValue" is not what you want. Giving a fixed value to all of the vector features that will be rasterized wont be useful if you want to play further with the data (e.g. create a DEM as you mention above). > How do I do this? --%<---code--%<--- # I downloaed the data you mention and did the following: v.in.e00 contours.e00 vect=contours type=line # check attribute table v.info -c contours v.info -c contours Displaying column types/names for database connection of layer 1: INTEGER|cat INTEGER|UserId INTEGER|FNODE_ INTEGER|TNODE_ INTEGER|LPOLY_ INTEGER|RPOLY_ DOUBLE PRECISION|LENGTH INTEGER|CONTOURS_ INTEGER|CONTOURS_I INTEGER|ELEV # match region ## I am unsure about the resolution (=look at the original data resolution from which the contours derived) g.region vect=contours res=SomeResolutionValue -pa # the last column is probably of your interest, so v.to.rast use=val value=attr col=ELEV --%<---code--%<--- Perhaps you do not even need to rasterise. Have a look at v.surf.rst [2]. Of course I am no expert with DEM's, v.surf.rst might not be what you need. Kind regards, Nikos --- [1] http://grass.osgeo.org/grass64/manuals/html64_user/v.to.rast.html [2] http://grass.osgeo.org/grass64/manuals/html64_user/v.surf.rst.html ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] shapefile, TIGER, or what for a dlg that is stored in .e00 format
I am trying to make a DEM from contour lines downloaded from here http://csat.er.usgs.gov/statewide/layers/contours.html I converted this to a shape file, reprojected it, and then v.to.rast use=value and got out a raster with a range of 1 to 1. How do I do this? If you require any more information please tell me and I can give it to you. Thanks for any help. Stephen Sefick -- Stephen Sefick Let's not spend our time and resources thinking about things that are so little or so large that all they really do for us is puff us up and make us feel like gods. We are mammals, and have not exhausted the annoying little problems of being mammals. -K. Mullis ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
