Re: [GRASS-user] floodplain creation
On Mon, Sep 24, 2018 at 6:33 PM Shane Carey wrote:
>
> This works well, but doesn't capture every river - is it a case of making
> the threshold value smaller or making a deeper carve in the rivers???
>
It's probably the threshold. How your rivers compare to the ones derived on
carved DEM?
>
> Thanks in advance - I think this method would will work well, if it were
> able to "flood" all rivers.
>
> On Sun, Sep 23, 2018 at 12:55 PM, Shane Carey wrote:
>
>> Thanks, I will compare them and let you know the differences.
>> Thanks
>>
>> On Domh 23 MFómh 2018 at 02:09, Vaclav Petras
>> wrote:
>>
>>> These are steps based on:
>>>
>>>
>>> https://grasswiki.osgeo.org/wiki/From_GRASS_GIS_novice_to_power_user_(workshop_at_FOSS4G_Boston_2017)#Hydrology:_Estimating_inundation_extent_using_HAND_methodology
>>>
>>> You need r.stream.distance module from Addons:
>>>
>>> g.extension r.stream.distance
>>>
>>> Get drainage and streams from your DEM (your carved DEM):
>>>
>>> r.watershed elevation=dem accumulation=flowacc drainage=drainage
>>> stream=streams threshold=10
>>>
>>> Compute height above nearest drainage/stream (HAND):
>>>
>>> r.stream.distance stream_rast=streams direction=drainage
>>> elevation=elevation method=downstream difference=hand
>>>
>>> Use r.lake not on the original DEM, but on the HAND and start flooding
>>> ("lake") from the streams:
>>>
>>> r.lake elevation=hand water_level=3 lake=flood_3m seed=streams
>>>
>>> Convert to vector if desired:
>>>
>>> r.to.vect -s input=flood_3m output=flood_3m type=area
>>>
>>> The difference to the r.grow+r.mapcalc method [1] is that this uses an
>>> addon module (there should be no problem installing it) and that r.grow
>>> uses euclidean distance for what is later used for height difference while
>>> r.steam.distance follows drainage and further that r.lake floods only the
>>> cells accessible to water unlike the r.mapcalc expression which just looks
>>> at height. The two methodological differences can be summarized as "not
>>> respecting the surrounding terrain enough." Anyway, the r.grow+r.mapcalc
>>> method can get you quite far and I would be interested in the comparison
>>> (will differ for different terrains).
>>>
>>> Best,
>>> Vaclav
>>>
>>> [1]
>>> https://lists.osgeo.org/pipermail/grass-user/2018-September/079134.html
>>>
>>> On Fri, Sep 21, 2018 at 11:39 AM Shane Carey
>>> wrote:
>>>
Hi All,
I have used r.carve to carve out the rivers of a DTM - a really super
job. I now need to pour 3meters of water into every cell in the river and
see how for this water extends out - onto the floodplain.
I was trying to use r.lake to do this, but unsure as to how r.lake will
work to pour 3 meters of water in every cell along the river network.
Any advice on this would be great. It is for the creation of a
floodplain.
Thanks
Le gach dea ghui,
*Shane Carey*
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>>>
>>> --
>> Le gach dea ghui,
>> *Shane Carey*
>> *GIS and Data Solutions Consultant*
>>
>
>
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Re: [GRASS-user] Interpolating rainfall data across area from points
On Tue, 25 Sep 2018, Pierre Roudier wrote: An alternative to kriging is the v.surf.tps add-on [1]. It implements TPS interpolation, with or without covariates. It is very similar to the ANUSPLIN procedure used to create the WorldClim layers [2]. Pierre, Thanks for the pointer and URLs. I'll certainly look carefully at them. Best regards, Rich ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Interpolating rainfall data across area from points
On Mon, 24 Sep 2018, Micha Silver wrote: The guidelines that I follow include: Micha, Markus, et al.: The data (exported from an R data.frame) has six columns: row number, coordinates (two columns in parentheses of easting and northing), site_name, elevation, and mean precipitation. I'll change the coordinates pair to separate easting and northing and could leave the row 48 numbers as categories unless it's advisable to allow GRASS to assign those numbers. Elevations range from ~45m to ~1200m, from the river at the bottom of the valley floor to the watershed on top of the mountain range. I'm working my way through the v.kriging manual page to understand all options and the process for applying the module to my data. My question is whether to do 2D or 3D kriging on this data set. Without any experience applying this module I've no basis for making a decision because I've no knowledge of which would be more appropriate. Your advice is needed. Regards, Rich ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] floodplain creation
Hi All,
This works well, but doesn't capture every river - is it a case of making
the threshold value smaller or making a deeper carve in the rivers???
Thanks in advance - I think this method would will work well, if it were
able to "flood" all rivers.
Thanks
Le gach dea ghui,
*Shane Carey*
*GIS and Data Solutions Consultant*
On Sun, Sep 23, 2018 at 12:55 PM, Shane Carey wrote:
> Thanks, I will compare them and let you know the differences.
> Thanks
>
> On Domh 23 MFómh 2018 at 02:09, Vaclav Petras
> wrote:
>
>> These are steps based on:
>>
>> https://grasswiki.osgeo.org/wiki/From_GRASS_GIS_novice_to_
>> power_user_(workshop_at_FOSS4G_Boston_2017)#Hydrology:
>> _Estimating_inundation_extent_using_HAND_methodology
>>
>> You need r.stream.distance module from Addons:
>>
>> g.extension r.stream.distance
>>
>> Get drainage and streams from your DEM (your carved DEM):
>>
>> r.watershed elevation=dem accumulation=flowacc drainage=drainage
>> stream=streams threshold=10
>>
>> Compute height above nearest drainage/stream (HAND):
>>
>> r.stream.distance stream_rast=streams direction=drainage
>> elevation=elevation method=downstream difference=hand
>>
>> Use r.lake not on the original DEM, but on the HAND and start flooding
>> ("lake") from the streams:
>>
>> r.lake elevation=hand water_level=3 lake=flood_3m seed=streams
>>
>> Convert to vector if desired:
>>
>> r.to.vect -s input=flood_3m output=flood_3m type=area
>>
>> The difference to the r.grow+r.mapcalc method [1] is that this uses an
>> addon module (there should be no problem installing it) and that r.grow
>> uses euclidean distance for what is later used for height difference while
>> r.steam.distance follows drainage and further that r.lake floods only the
>> cells accessible to water unlike the r.mapcalc expression which just looks
>> at height. The two methodological differences can be summarized as "not
>> respecting the surrounding terrain enough." Anyway, the r.grow+r.mapcalc
>> method can get you quite far and I would be interested in the comparison
>> (will differ for different terrains).
>>
>> Best,
>> Vaclav
>>
>> [1] https://lists.osgeo.org/pipermail/grass-user/2018-
>> September/079134.html
>>
>> On Fri, Sep 21, 2018 at 11:39 AM Shane Carey wrote:
>>
>>> Hi All,
>>>
>>> I have used r.carve to carve out the rivers of a DTM - a really super
>>> job. I now need to pour 3meters of water into every cell in the river and
>>> see how for this water extends out - onto the floodplain.
>>>
>>> I was trying to use r.lake to do this, but unsure as to how r.lake will
>>> work to pour 3 meters of water in every cell along the river network.
>>>
>>> Any advice on this would be great. It is for the creation of a
>>> floodplain.
>>>
>>> Thanks
>>>
>>>
>>> Le gach dea ghui,
>>> *Shane Carey*
>>>
>>> ___
>>> grass-user mailing list
>>> grass-user@lists.osgeo.org
>>> https://lists.osgeo.org/mailman/listinfo/grass-user
>>
>> --
> Le gach dea ghui,
> *Shane Carey*
> *GIS and Data Solutions Consultant*
>
___
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Re: [GRASS-user] Interpolating rainfall data across area from points
On Mon, 24 Sep 2018, Markus Neteler wrote: Might this addon be of any use? https://grass.osgeo.org/grass7/manuals/addons/v.kriging.html Markus, Of course! I had not checked the addon manuals before writing and suspected the module was there because I did not find it in the core modules. Many thanks, Rich ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Interpolating rainfall data across area from points
On Mon, 24 Sep 2018, Micha Silver wrote: The guidelines that I follow include: * Rainfall interpolation (of any kind) should be done only for long time periods = at least a full season. since you are looking at 13 years of data then this requirement is fulfilled. * The rules of thumb for "how many points" for kriging interpolation usually says > 30. So again you are fine. * The GRASS modules offer only ordinary kriging AFAIK, which might be appropriate in this case. But if you want to use Kriging with External Drift with the elevation as the secondary "trend" variable, I think you'll need to go with with R. Having said that, I think that "the jury is still out" on whether elevation improves the interpolation or not. Micha, Thanks for the insights. I think that OK would be adequate for now because the climate is changing and this is a long-term project that will be monitored and and adjusted as necessary, Regards, Rich ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Interpolating rainfall data across area from points
On Mon, Sep 24, 2018 at 5:32 PM Rich Shepard wrote: > >I want to determine whether GRASS or R is best suited to > interpolating/extrapolating annual mean precipitation data from 58 reporting > stations (unevenly distributed within the county) across the county. Some > flavor of kriging would be applied to these data to illustrate a general > long-term pattern of rainfall. Might this addon be of any use? https://grass.osgeo.org/grass7/manuals/addons/v.kriging.html Best Markus ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Interpolating rainfall data across area from points
Hi Rich On 09/24/2018 06:32 PM, Rich Shepard wrote: I want to determine whether GRASS or R is best suited to interpolating/extrapolating annual mean precipitation data from 58 reporting stations (unevenly distributed within the county) across the county. Some flavor of kriging would be applied to these data to illustrate a general long-term pattern of rainfall. Some years ago there was both a static display of a chemical constituent in a river reach, a "heat map", (and an automation of temporal changes, if I correctly recall) and I'm not finding this in the web site galleries. While elevation could be included as an explanatory variable using regression kriging my purpose is to illustrate county-wide mean annual rainfall distribution over a 13 year period, not to interpolate values for specific, unsampled locations. Please provide some thoughts on the work flow to do this within GRASS. I'm digging into the gstat docs to get a sense of how to do this within R (and I have the rgrass7 package working well; it imported the GRASS county boundary map which I converted to a SpatialPolygonDataFrame.) The guidelines that I follow include: Rainfall interpolation (of any kind) should be done only for long time periods = at least a full season. since you are looking at 13 years of data then this requirement is fulfilled. The rules of thumb for "how many points" for kriging interpolation usually says > 30. So again you are fine. The GRASS modules offer only ordinary kriging AFAIK, which might be appropriate in this case. But if you want to use Kriging with External Drift with the elevation as the secondary "trend" variable, I think you'll need to go with with R. Having said that, I think that "the jury is still out" on whether elevation improves the interpolation or not. Regards, Micha Rich ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user -- Micha Silver Ben Gurion Univ. Sde Boker, Remote Sensing Lab cell: +972-523-665918 ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Interpolating rainfall data across area from points
I want to determine whether GRASS or R is best suited to interpolating/extrapolating annual mean precipitation data from 58 reporting stations (unevenly distributed within the county) across the county. Some flavor of kriging would be applied to these data to illustrate a general long-term pattern of rainfall. Some years ago there was both a static display of a chemical constituent in a river reach, a "heat map", (and an automation of temporal changes, if I correctly recall) and I'm not finding this in the web site galleries. While elevation could be included as an explanatory variable using regression kriging my purpose is to illustrate county-wide mean annual rainfall distribution over a 13 year period, not to interpolate values for specific, unsampled locations. Please provide some thoughts on the work flow to do this within GRASS. I'm digging into the gstat docs to get a sense of how to do this within R (and I have the rgrass7 package working well; it imported the GRASS county boundary map which I converted to a SpatialPolygonDataFrame.) Rich ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Identify duplicate points
On Fri, Sep 21, 2018 at 1:13 PM Johannes Radinger wrote: > Hi all, > > this is maybe a very easy question: But how is it possible to identify > duplicate points (that have the same pair of coordinates) of a set of points. > I'd like to get the categories of all non-single (i.e.duplicate/triplicate > etc.) points. I know that I could use the 'rmdupl' tool from v.clean to > remove duplicate geometries but I'd rather like to manually select the > duplicate points I'd like to remove. Therefore, I'd need to identify the > points with similar geometries first. I thought of using v.distance to get > the all points that have 0 distance from another point but the result is 0 > for all points (due to the self-distance which is 0 of course). I could > update the X,Y coordinates of each point and the use a SQL command to > identify points with similar coordinate pairs; however, is there a more > direct way or tool in GRASS to perform such a task? Did you see https://grasswiki.osgeo.org/wiki/Find_multiple_points_in_same_position ? HTH, Markus ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Get map from https://lst.mundialis.de in GRASS GIS' data base
On Mon, Sep 24, 2018 at 5:00 PM Markus Neteler wrote: > On Fri, Sep 21, 2018 at 5:31 PM Nikos Alexandris > > Dears, > > > > can I get a fraction (spatial and temporal) of the maps shown under > > https://lst.mundialis.de/, directly in GRASS GIS? > > Consider to contact mundialis for this :-) As a side note: we published the global monthly MODIS LST data related to the article: Metz, M.; Andreo, V.; Neteler, M. A New Fully Gap-Free Time Series of Land Surface Temperature from MODIS LST Data. Remote Sens. 2017, 9, 1333. https://doi.org/10.3390/rs9121333 here: https://zenodo.org/record/1135230 best, Markus ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Get map from https://lst.mundialis.de in GRASS GIS' data base
On Fri, Sep 21, 2018 at 5:31 PM Nikos Alexandris wrote: > Dears, > > can I get a fraction (spatial and temporal) of the maps shown under > https://lst.mundialis.de/, directly in GRASS GIS? Consider to contact mundialis for this :-) best, Markus ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Raster Attribute Tables
On Fri, Sep 21, 2018 at 9:43 PM Markus Metz wrote: > On Thu, Sep 20, 2018 at 10:36 PM Stefan Blumentrath > wrote: > > > > Hi Chris, > > > > Did you try the table option in r.in.gdal: > > https://grass.osgeo.org/grass74/manuals/r.in.gdal.html > > yes, r.in.gdal can dump raster attribute tables as csv files. Moreover, > information in raster attribute tables is automatically imported as long as > the field definitions contain information about how to use a field, e.g. for > color information or for labels. BTW: I have added that to the manual page of r.in.gdal. markusN ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] i.modis and missing support for HFD4 under Gentoo/Funtoo-Linux
Dears, I am trying to use `i.modis.download`. There is this message "GDAL installation has no support for HDF4, please update GDAL" that won't let the module run at all. Strangely, there is no 'hdf' use flag (Gentoo/Funtoo terminology) for gdal (anymore?). Any Gentoo users? Thank you, Nikos signature.asc Description: PGP signature ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
