Re: [GRASS-user] Re: r.watershed: pretty flat areas
Markus Metz pisze: On Wed, May 12, 2010 at 9:00 PM, Hamish hamis...@yahoo.com wrote: before after screenshots welcome :) before: http://sites.google.com/site/markusmetzgiswork/accumulation_regular.png after: http://sites.google.com/site/markusmetzgiswork/accumulation_beautified.png less straight flow, main flow is more centered in the lake. I can't say if this is more accurate, but it looks nicer. It's not perfect, see south-eastern part of the lake. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user Hi As a way to proper drainage network topology it looks almost perfect. In DEM there is no information (if lake is represented by flat area on DEM) about flow structure in the lake so that approach looks good for me, if real flow is unknown! Good work Markus! J. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Re: r.watershed: pretty flat areas
Nice! Many thanks Markus. Annalisa 2010/5/13 Jarosław Jasiewicz jar...@amu.edu.pl Markus Metz pisze: On Wed, May 12, 2010 at 9:00 PM, Hamish hamis...@yahoo.com wrote: before after screenshots welcome :) before: http://sites.google.com/site/markusmetzgiswork/accumulation_regular.png after: http://sites.google.com/site/markusmetzgiswork/accumulation_beautified.png less straight flow, main flow is more centered in the lake. I can't say if this is more accurate, but it looks nicer. It's not perfect, see south-eastern part of the lake. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user Hi As a way to proper drainage network topology it looks almost perfect. In DEM there is no information (if lake is represented by flat area on DEM) about flow structure in the lake so that approach looks good for me, if real flow is unknown! Good work Markus! J. ___ 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
[GRASS-user] dems from coordinate lists
Hi, I've obtained DEMs in text files with columns X, Y and Z at 25m spacing. The first three entries in the text file are: - X,Y,Z 99550,2.9883e+06,1473.47 99550,2.98828e+06,1473.57 99550,2.98825e+06,1473.63 - To me it seems the easiest way to import these is the following: 1. v.in.ascii 2. Set the region to the extents of new vector file and the resolution to 25m. 3. v.to.rast. This 'works' but I get horizontal strips of no data in my raster DEM at 25m spacings. Also, when I look at the raster and the vector layer together, the vector points are not always on the edges of the raster cells. Can someone perhaps help me to fix this? g.region: projection: 99 (Transverse Mercator) zone: 0 datum: ** unknown (default: WGS84) ** ellipsoid: wgs84 north: 2988300 south: 2959850 west: 74300 east: 99550 nsres: 25 ewres: 25 rows: 1138 cols: 1010 cells: 1149380 v.info: ++ | Layer: dem_2628cc_...@c83 | Mapset: C83 | Location:sa_tm_19deg_E | Database:C:\Hanlie\grassdata | Title: | Map scale: 1:1 | Map format: native | Name of creator: Administrator | Organization: | Source date: Thu May 13 16:06:07 2010 || | Type of Map: vector (level: 2) | | Number of points: 1151529 Number of areas: 0 | Number of lines:0 Number of islands:0 | Number of boundaries: 0 Number of faces: 0 | Number of centroids:0 Number of kernels:0 | | Map is 3D: Yes | Number of dblinks: 0 | | Projection: Transverse Mercator | N: 2988300S: 2959850 | E: 99550W: 74300 | B: 1429.79T:1740.2 | | Digitization threshold: 0 | Comments: | ++ r.info: ++ | Layer:dem_2628cc_...@c83 Date: Thu May 13 16:15:50 2010 | Mapset: C83Login of Creator: Administrator | Location: sa_tm_19deg_E | DataBase: C:\Hanlie\grassdata | Title:Categories ( dem_2628cc_25m ) | Timestamp: none || || | Type of Map: raster Number of Categories: 0 | Data Type:DCELL | Rows: 1138 | Columns: 1010 | Total Cells: 1149380 |Projection: Transverse Mercator |N:2988300S:2959850 Res:25 |E: 99550W: 74300 Res:25 | Range of data:min = 1429.85 max = 1739.41 | | Data Source: |Vector Map: dem_2628cc_...@c83 in mapset C83 |Original scale from vector map: 1:1 | | Data Description: |generated by v.to.rast | | Comments: |v.to.rast input=dem_2628cc_...@c83 output=dem_2628cc_25m use=z\ | type=point,line,area layer=1 value=1 rows=4096 | ++ Thanks Hanlie ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] dems from coordinate lists
You want the points to represent cell centers so you need to expand your region 1/2 pixel in all four directions. Also look at using r.in.xyz, it works directly on this type of data. Jamie On Thu, May 13, 2010 at 7:26 AM, Hanlie Pretorius hanlie.pretor...@gmail.com wrote: Hi, I've obtained DEMs in text files with columns X, Y and Z at 25m spacing. The first three entries in the text file are: - X,Y,Z 99550,2.9883e+06,1473.47 99550,2.98828e+06,1473.57 99550,2.98825e+06,1473.63 - To me it seems the easiest way to import these is the following: 1. v.in.ascii 2. Set the region to the extents of new vector file and the resolution to 25m. 3. v.to.rast. This 'works' but I get horizontal strips of no data in my raster DEM at 25m spacings. Also, when I look at the raster and the vector layer together, the vector points are not always on the edges of the raster cells. Can someone perhaps help me to fix this? g.region: projection: 99 (Transverse Mercator) zone: 0 datum: ** unknown (default: WGS84) ** ellipsoid: wgs84 north: 2988300 south: 2959850 west: 74300 east: 99550 nsres: 25 ewres: 25 rows: 1138 cols: 1010 cells: 1149380 v.info: ++ | Layer: dem_2628cc_...@c83 | Mapset: C83 | Location:sa_tm_19deg_E | Database:C:\Hanlie\grassdata | Title: | Map scale: 1:1 | Map format: native | Name of creator: Administrator | Organization: | Source date: Thu May 13 16:06:07 2010 || | Type of Map: vector (level: 2) | | Number of points: 1151529 Number of areas: 0 | Number of lines:0 Number of islands:0 | Number of boundaries: 0 Number of faces: 0 | Number of centroids:0 Number of kernels:0 | | Map is 3D: Yes | Number of dblinks: 0 | | Projection: Transverse Mercator | N: 2988300S: 2959850 | E: 99550W: 74300 | B: 1429.79T:1740.2 | | Digitization threshold: 0 | Comments: | ++ r.info: ++ | Layer:dem_2628cc_...@c83 Date: Thu May 13 16:15:50 2010 | Mapset: C83Login of Creator: Administrator | Location: sa_tm_19deg_E | DataBase: C:\Hanlie\grassdata | Title:Categories ( dem_2628cc_25m ) | Timestamp: none || | | | Type of Map: raster Number of Categories: 0 | Data Type:DCELL | Rows: 1138 | Columns: 1010 | Total Cells: 1149380 |Projection: Transverse Mercator |N:2988300S:2959850 Res:25 |E: 99550W: 74300 Res:25 | Range of data:min = 1429.85 max = 1739.41 | | Data Source: |Vector Map: dem_2628cc_...@c83 in mapset C83 |Original scale from vector map: 1:1 | | Data Description: |generated by v.to.rast | | Comments: |v.to.rast input=dem_2628cc_...@c83 output=dem_2628cc_25m use=z\ | type=point,line,area layer=1 value=1 rows=4096 | ++ Thanks Hanlie ___ 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
[GRASS-user] Re: dems from coordinate lists
Hi Jamie, I tried r.in.xyz: (r.in.xyz input=2628cc.ORT.xyz output=dem_2628cc_25m_xyz method=mean type=FCELL x=1 y=2 z=3 zscale=1.0 percent=100) but I still get the rows of no data in the result. Hanlie You want the points to represent cell centers so you need to expand your region 1/2 pixel in all four directions. Also look at using r.in.xyz, it works directly on this type of data. Jamie On Thu, May 13, 2010 at 7:26 AM, Hanlie Pretorius hanlie.pretor...@gmail.com wrote: Hi, I've obtained DEMs in text files with columns X, Y and Z at 25m spacing. The first three entries in the text file are: - X,Y,Z 99550,2.9883e+06,1473.47 99550,2.98828e+06,1473.57 99550,2.98825e+06,1473.63 - To me it seems the easiest way to import these is the following: 1. v.in.ascii 2. Set the region to the extents of new vector file and the resolution to 25m. 3. v.to.rast. This 'works' but I get horizontal strips of no data in my raster DEM at 25m spacings. Also, when I look at the raster and the vector layer together, the vector points are not always on the edges of the raster cells. Can someone perhaps help me to fix this? g.region: projection: 99 (Transverse Mercator) zone: 0 datum: ** unknown (default: WGS84) ** ellipsoid: wgs84 north: 2988300 south: 2959850 west: 74300 east: 99550 nsres: 25 ewres: 25 rows: 1138 cols: 1010 cells: 1149380 v.info: ++ | Layer: dem_2628cc_...@c83 | Mapset: C83 | Location:sa_tm_19deg_E | Database:C:\Hanlie\grassdata | Title: | Map scale: 1:1 | Map format: native | Name of creator: Administrator | Organization: | Source date: Thu May 13 16:06:07 2010 || | Type of Map: vector (level: 2) | | Number of points: 1151529 Number of areas: 0 | Number of lines:0 Number of islands:0 | Number of boundaries: 0 Number of faces: 0 | Number of centroids:0 Number of kernels:0 | | Map is 3D: Yes | Number of dblinks: 0 | | Projection: Transverse Mercator | N: 2988300S: 2959850 | E: 99550W: 74300 | B: 1429.79T:1740.2 | | Digitization threshold: 0 | Comments: | ++ r.info: ++ | Layer:dem_2628cc_...@c83 Date: Thu May 13 16:15:50 2010 | Mapset: C83Login of Creator: Administrator | Location: sa_tm_19deg_E | DataBase: C:\Hanlie\grassdata | Title:Categories ( dem_2628cc_25m ) | Timestamp: none || | | | Type of Map: raster Number of Categories: 0 | Data Type:DCELL | Rows: 1138 | Columns: 1010 | Total Cells: 1149380 |Projection: Transverse Mercator |N:2988300S:2959850 Res:25 |E: 99550W: 74300 Res:25 | Range of data:min = 1429.85 max = 1739.41 | | Data Source: |Vector Map: dem_2628cc_...@c83 in mapset C83 |Original scale from vector map: 1:1 | | Data Description: |generated by v.to.rast | | Comments: |v.to.rast input=dem_2628cc_...@c83 output=dem_2628cc_25m use=z\ | type=point,line,area layer=1 value=1 rows=4096 | ++ Thanks Hanlie ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user -- next part -- An HTML attachment was scrubbed... URL: http://lists.osgeo.org/pipermail/grass-user/attachments/20100513/dd33d293/attachment.html -- ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user End of grass-user Digest, Vol 49, Issue 24 ** ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Re: dems from coordinate lists
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Re: [GRASS-user] dems from coordinate lists
If I follow correctly, instead of v.to.rast, you need to interpolate a raster DEM from the points. v.surf.rst produces nice results, but there are other interpolation modules as well in the raster category. Best regards, Mark On May 13, 2010, at 10:26 AM, Hanlie Pretorius hanlie.pretor...@gmail.com wrote: Hi, I've obtained DEMs in text files with columns X, Y and Z at 25m spacing. The first three entries in the text file are: - X,Y,Z 99550,2.9883e+06,1473.47 99550,2.98828e+06,1473.57 99550,2.98825e+06,1473.63 - To me it seems the easiest way to import these is the following: 1. v.in.ascii 2. Set the region to the extents of new vector file and the resolution to 25m. 3. v.to.rast. This 'works' but I get horizontal strips of no data in my raster DEM at 25m spacings. Also, when I look at the raster and the vector layer together, the vector points are not always on the edges of the raster cells. Can someone perhaps help me to fix this? g.region: projection: 99 (Transverse Mercator) zone: 0 datum: ** unknown (default: WGS84) ** ellipsoid: wgs84 north: 2988300 south: 2959850 west: 74300 east: 99550 nsres: 25 ewres: 25 rows: 1138 cols: 1010 cells: 1149380 v.info: +-- --- --- + | Layer: dem_2628cc_...@c83 | Mapset: C83 | Location:sa_tm_19deg_E | Database:C:\Hanlie\grassdata | Title: | Map scale: 1:1 | Map format: native | Name of creator: Administrator | Organization: | Source date: Thu May 13 16:06:07 2010 |-- --- --- | | Type of Map: vector (level: 2) | | Number of points: 1151529 Number of areas: 0 | Number of lines:0 Number of islands:0 | Number of boundaries: 0 Number of faces: 0 | Number of centroids:0 Number of kernels:0 | | Map is 3D: Yes | Number of dblinks: 0 | | Projection: Transverse Mercator | N: 2988300S: 2959850 | E: 99550W: 74300 | B: 1429.79T:1740.2 | | Digitization threshold: 0 | Comments: | +-- --- --- + r.info: +-- --- --- + | Layer:dem_2628cc_...@c83 Date: Thu May 13 16:15:50 2010 | Mapset: C83Login of Creator: Administrator | Location: sa_tm_19deg_E | DataBase: C:\Hanlie\grassdata | Title:Categories ( dem_2628cc_25m ) | Timestamp: none |-- --- --- | | | | Type of Map: raster Number of Categories: 0 | Data Type:DCELL | Rows: 1138 | Columns: 1010 | Total Cells: 1149380 |Projection: Transverse Mercator |N:2988300S:2959850 Res:25 |E: 99550W: 74300 Res:25 | Range of data:min = 1429.85 max = 1739.41 | | Data Source: |Vector Map: dem_2628cc_...@c83 in mapset C83 |Original scale from vector map: 1:1 | | Data Description: |generated by v.to.rast | | Comments: |v.to.rast input=dem_2628cc_...@c83 output=dem_2628cc_25m use=z\ | type=point,line,area layer=1 value=1 rows=4096 | +-- --- --- + Thanks Hanlie ___ 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] dems from coordinate lists
MS wrote: If I follow correctly, instead of v.to.rast, you need to interpolate a raster DEM from the points. v.surf.rst produces nice results, but there are other interpolation modules as well in the raster category. That's the method I use also. I start with: v.in.ascii -z in=ascii_file z=3 out=vect_pts This creates a 3D vector using the z column as the height values. Now set the desired region: g.region vect=vect_pts res=xxx Choose the raster resolution that suits your needs. If the points in the ascii file are at 25 m spacing, then you probably could interpolate at 10m-20m resolution (or better) with no problems. Then: v.surf.rst in=vect_pts layer=0 elev=dem ... The layer=0 parameter indicates that you're using the 3D vector's z value for elevation. -- Micha Best regards, Mark On May 13, 2010, at 10:26 AM, Hanlie Pretorius hanlie.pretor...@gmail.com wrote: Hi, I've obtained DEMs in text files with columns X, Y and Z at 25m spacing. The first three entries in the text file are: - X,Y,Z 99550,2.9883e+06,1473.47 99550,2.98828e+06,1473.57 99550,2.98825e+06,1473.63 - To me it seems the easiest way to import these is the following: 1. v.in.ascii 2. Set the region to the extents of new vector file and the resolution to 25m. 3. v.to.rast. This 'works' but I get horizontal strips of no data in my raster DEM at 25m spacings. Also, when I look at the raster and the vector layer together, the vector points are not always on the edges of the raster cells. Can someone perhaps help me to fix this? g.region: projection: 99 (Transverse Mercator) zone: 0 datum: ** unknown (default: WGS84) ** ellipsoid: wgs84 north: 2988300 south: 2959850 west: 74300 east: 99550 nsres: 25 ewres: 25 rows: 1138 cols: 1010 cells: 1149380 v.info: ++ | Layer: dem_2628cc_...@c83 | Mapset: C83 | Location:sa_tm_19deg_E | Database:C:\Hanlie\grassdata | Title: | Map scale: 1:1 | Map format: native | Name of creator: Administrator | Organization: | Source date: Thu May 13 16:06:07 2010 || | Type of Map: vector (level: 2) | | Number of points: 1151529 Number of areas: 0 | Number of lines:0 Number of islands:0 | Number of boundaries: 0 Number of faces: 0 | Number of centroids:0 Number of kernels:0 | | Map is 3D: Yes | Number of dblinks: 0 | | Projection: Transverse Mercator | N: 2988300S: 2959850 | E: 99550W: 74300 | B: 1429.79T:1740.2 | | Digitization threshold: 0 | Comments: | ++ r.info: ++ | Layer:dem_2628cc_...@c83 Date: Thu May 13 16:15:50 2010 | Mapset: C83Login of Creator: Administrator | Location: sa_tm_19deg_E | DataBase: C:\Hanlie\grassdata | Title:Categories ( dem_2628cc_25m ) | Timestamp: none || | | | Type of Map: raster Number of Categories: 0 | Data Type:DCELL | Rows: 1138 | Columns: 1010 | Total Cells: 1149380 |Projection: Transverse Mercator |N:2988300S:2959850 Res:25 |E: 99550W: 74300 Res:25 | Range of data:min = 1429.85 max = 1739.41 | | Data Source: |Vector Map: dem_2628cc_...@c83 in mapset C83 |Original scale from vector map: 1:1 | | Data Description: |generated by v.to.rast | | Comments: |v.to.rast input=dem_2628cc_...@c83 output=dem_2628cc_25m use=z\ | type=point,line,area layer=1 value=1 rows=4096 | ++ Thanks Hanlie ___ 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 This mail was received via Mail-SeCure System. -- Micha Silver Arava Development Co. +972-52-3665918 http://www.surfaces.co.il ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] help(r.walk and r.cost and ogr)
hello all, I'm developing a pywps geoprocess in calculating accessibility, I saw a command called r.walk and r.cost not how viable is to use my project as: composite, I would like to share their experiences with these commands, downside is that the input data are vector network ogr I recommend to process attributes to network with their raster, or that would be the most appropriate to make these calculations, I just need a basic procedure thanks for your answers and suggestions Ricardo Rodríguez Univalle ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Copying from a mapset in another data directory
I have some rasters in a grass data directory on a different mounted drive in unix that i want to copy into a different data directory + mapset -- i can't seem to figure out how to do this with g.copy, which AFAIK only copies from mapsets within a given data directory. Thoughts? --j ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Latitude/Longitude vs UTM
Hi Folks, I have been playing with the seamless maps from the USGS. Specifically, my question is on the effect of Latitude/Longitude vs UTM with respect to hydrology modules such as r.watershed and r.topidx. I was trying to generate watershed maps with r.watershed. I've done this before for my dissertation. They did not turn out the same. They looked strange compared to what I generated before. Moreover, they maps kept falling in the same place in the map set regardless of what I turned off or on. (i.e. some where in the center top, when the map was generated from a dem on the bottom.) I then tried to run r.topidx. This was interesting in that it told me that r.topidx could not be run with latitude and longitude and I had to convert to UTM. I was wondering if this is the answer to the problem and I just had to convert to UTM. One other question. New Hampshire appears to fall within two UTM zones (19T and 20T) Is there a way for a maps set to contain two UTM zones? Thanks for any help. Kurt Springs ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
