[GRASS-user] Re: Need some help in converting a contour map to DEM map...
hello sir I have a LANDSAT image imported in my mapset using r.in.gdal. I used r.composite to combine the rgb files. After all these, now if I wants to get the pixel value on click of a mouse on the raster map. Is it possible for me to somehow get the pixel value (that is red, blue and green color values which should lie within 0-255 range) on click. I need some help. Thanks in advance.. Nikhil -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/Need-some-help-in-converting-a-contour-map-to-DEM-map-tp5720519p5783680.html Sent from the Grass - Users mailing list archive at Nabble.com. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Re: Need some help in converting a contour map to DEM map...
On 29/11/2010 11:18, nikmor wrote: hello sir I have a LANDSAT image imported in my mapset using r.in.gdal. I used r.composite to combine the rgb files. After all these, now if I wants to get the pixel value on click of a mouse on the raster map. Is it possible for me to somehow get the pixel value (that is red, blue and green color values which should lie within 0-255 range) on click. I need some help. Yes, *before* you combine the bands. If you select one band and use the query button in the GUI interface, you'll get the pixel value of that band at the click location. Thanks in advance.. Nikhil -- Micha Silver http://www.surfaces.co.il/ Arava Development Co. +972-52-3665918 ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Re: Need some help in converting a contour map to DEM map...
of the DEM after exagerating it.Now I am looking forward to drape an aerial image of the same area on the DEM that I have got. In order to do this I loaded the DEM map and then draped the imported aerial map (imported using r.in.gdal, but that single jpeg image(satimage.jpg) got imported into 3 different maps namely satimage.red, satimage.green, satimage.blue, therefore is just draped only one of it on the DEM). The output view that I get seems okay but its too dark (black and white-- please see the attachment), though the original aerial image was colourful which I had imported. Why is it happening so?? Can any one help me with this. Hi Nikhil, take a look at http://grass.fbk.eu/grass64/manuals/html64_user/imageryintro.html it might give you a good introduction. especially this part: Visualizing (true) color composites To quickly combine the first three channels to a near natural color image, the GRASS command d.rgb can be used or the graphical GIS manager (gis.m). It assigns each channel to a color which is then mixed while displayed. With a bit more work of tuning the grey scales of the channels, nearly perfect colors can be achieved. Channel histograms can be shown with d.histogram. Regards, Achim ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Re: Need some help in converting a contour map to DEM map...
Hello sir Thanks for the link. I finally got the coloured aerial image draped on the DEM map and which can be viewed in nviz. Since the aerial image was getting imported in an rgb files (3 different files) I first needed to combine them into one raster map, which could be done using r.composite. which takes in these 3 files (.red, .green, .blue) and one output map name of users choice. Thanks once again for your help sir. Nikhil Morajkar Junior Software Engineer, Department of Computer Science and Engineering, Geo-Spatial Information Science Engineering (GISE), Advance Research Lab, Indian Institute of Technology, Bombay (IITB) Powai, Mumbai -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/Need-some-help-in-converting-a-contour-map-to-DEM-map-tp5720519p5732236.html Sent from the Grass - Users mailing list archive at Nabble.com. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Re: Need some help in converting a contour map to DEM map...
hello sir, thanks for the link. I have tried it out and it works with v.surf.rst. But when I use r.surf.contour it takes a very very long time and it never ends. I would be thankful if you could suggest me something regarding the resolution(grid resolution 2d in g.region modules resolution tab). thanks, Nikhil Morajkar Junior Software Engineer, Department of Computer Science and Engineering, Geo-Spatial Information Science Engineering (GISE), Advance Research Lab, Indian Institute of Technology, Bombay (IITB) Powai, Mumbai --- On Wed, 11/10/10, Markus Neteler [via OSGeo.org] ml-node+5723857-989940413-299...@n2.nabble.com wrote: From: Markus Neteler [via OSGeo.org] ml-node+5723857-989940413-299...@n2.nabble.com Subject: Re: Need some help in converting a contour map to DEM map... To: nikmor nikhil_moraj...@yahoo.com Date: Wednesday, November 10, 2010, 2:00 PM On Tue, Nov 9, 2010 at 12:28 PM, nikmor [hidden email] wrote: Hello friends I am trying to import an contour file and trying to come up with an DEM map from it. I tried it my way but end up with wrong output. I am looking forward for some one who can import this map and convert it to DEM and finally and most importantly we should be able to view the output in NVIZ. I have attached the folder having the contour data, this data is of IIT bombay. Please take a look here. http://grass.osgeo.org/wiki/Contour_lines_to_DEM Markus ___ grass-user mailing list [hidden email] http://lists.osgeo.org/mailman/listinfo/grass-user View message @ http://osgeo-org.1803224.n2.nabble.com/Need-some-help-in-converting-a-contour-map-to-DEM-map-tp5720519p5723857.html To unsubscribe from Need some help in converting a contour map to DEM map..., click here. -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/Need-some-help-in-converting-a-contour-map-to-DEM-map-tp5720519p5724458.html Sent from the Grass - Users mailing list archive at Nabble.com. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Re: Need some help in converting a contour map to DEM map...
On 10/11/2010 14:20, nikmor wrote: hello sir, thanks for the link. I have tried it out and it works with v.surf.rst. But when I use r.surf.contour it takes a very very long time and it never ends. I would be thankful if you could suggest me something regarding the resolution(grid resolution 2d in g.region modules resolution tab). You can set the resolution to whatever you want. But choosing a reasonable resolution depends on your source data and how large an area you are working with. The contour lines you sent were at 5 m spacing, and the area seems to be only 0.02 deg ~= 2 km. So you can try a small resolution, such as 1 meter. So if you run (from the command line) g.region vect=contour res=0:00:00.03 -p This should set the region to the extent of the contour vector, and resolution to 3/100 arcsec or about 1 meter. Your raster will be about 2000X2500 ( ~ 5,000,000 cells), and any modern computer can do raster operations on that size in a reasonable time. thanks, Nikhil Morajkar Junior Software Engineer, Department of Computer Science and Engineering, Geo-Spatial Information Science Engineering (GISE), Advance Research Lab, Indian Institute of Technology, Bombay (IITB) Powai, Mumbai --- On Wed, 11/10/10, Markus Neteler [via OSGeo.org] [hidden email] wrote: From: Markus Neteler [via OSGeo.org] [hidden email] Subject: Re: Need some help in converting a contour map to DEM map... To: "nikmor" [hidden email] Date: Wednesday, November 10, 2010, 2:00 PM On Tue, Nov 9, 2010 at 12:28 PM, nikmor [hidden email] wrote: Hello friends I am trying to import an contour file and trying to come up with an DEM map from it. I tried it my way but end up with wrong output. I am looking forward for some one who can import this map and convert it to DEM and finally and most importantly we should be able to view the output in NVIZ. I have attached the folder having the contour data, this data is of IIT bombay. Please take a look here. http://grass.osgeo.org/wiki/Contour_lines_to_DEM Markus ___ grass-user mailing list [hidden email] http://lists.osgeo.org/mailman/listinfo/grass-user View message @ http://osgeo-org.1803224.n2.nabble.com/Need-some-help-in-converting-a-contour-map-to-DEM-map-tp5720519p5723857.html To unsubscribe from Need some help in converting a contour map to DEM map..., click here. View this message in context: Re: Need some help in converting a contour map to DEM map... Sent from the Grass - Users mailing list archive at Nabble.com. This mail was received via Mail-SeCure System. ___ 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 http://www.surfaces.co.il/ Arava Development Co. +972-52-3665918 ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Re: Need some help in converting a contour map to DEM map...
hey Achim Thanks for replying.I tried many things like v.surf.rst, r.surf.contour etc but still I could'nt get the desired output, sometimes it runs for a long-long time which never ends and sometimes after the resolution being changed it gives weird output and which cannot be viewed in NVIZ it says loading failed. I had posted the problems that I faced but did not get reply/help, so this time around I have uploaded the datafile so that one can just try out the thing on their machine and see if its possible and works fine on their system and kindly help me in my work. I have spent more than 2 weeks on this and have not succeeded yet. I think the problem is with resolution. I need serious help from someone. thanks Nikhil -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/Need-some-help-in-converting-a-contour-map-to-DEM-map-tp5720519p5720649.html Sent from the Grass - Users mailing list archive at Nabble.com. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Re: Need some help in converting a contour map to DEM map...
hey, I think the output you got is correct. But when i try to change the resolution (eg: 0:00:01) in the g.region resolution tab(GRID resolution 2D both north-south and east-west), it gives an error saying :ERROR: Invalid input res=0:00:01. Am i doing something wrong???. And one more thing is that how have you converted the height to integer please give me details of this too. I am really very thankful for your time and effort. regards Nikhil -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/Need-some-help-in-converting-a-contour-map-to-DEM-map-tp5720519p5723699.html Sent from the Grass - Users mailing list archive at Nabble.com. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Re: Need some help in converting a contour map to DEM map...
Hi Nikhil, And one more thing is that how have you converted the height to integer please give me details of this too. I am really very thankful for your time and effort. There are many ways. For example like Micha said: --%-- I'm including a mapset bombay with the contour vecto, the contour raster and the resulting dem. Like Achim said, first you must convert the HEIGHT column to integer (I did this with Openoffice Calc). --%-- here he means the dbf-file or you change the table after imported (using SQL) I think the output you got is correct. But when i try to change the resolution (eg: 0:00:01) in the g.region resolution tab(GRID resolution 2D both north-south and east-west), it gives an error saying :ERROR: Invalid inputres=0:00:01. Am i doing something wrong???. check your projection units (g.proj -p) and your region (g.region -p) Regards, Achim ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
