Dear R users,
I need to produce rainfall maps using R.
I know that this is possible, I looked though the web, I found the example below
reported (the author is Andrew Tredennick).
I would ask you if this is the most performing way to make rainfall maps; if yes
would someone be able to give me an example of how file.asc and pointfile.csv
should be? If no would somebody please show me another way providing a small
example?
Thank you for your help
Stefano
library(raster)
library(ggplot2)
#open ASCII file using ?raster? command, which converts the ASCII to a raster
object
map <- raster(?/your/path/to/file.asc?)
#convert the raster to points for plotting
map.p <- rasterToPoints(map)
#Make the points a dataframe for ggplot
df <- data.frame(map.p)
#Make appropriate column headings
colnames(df) <- c(?Longitude?, ?Latitude?, ?MAP?)
#Call in point data, in this case a fake transect (csv file with lat and lon
coordinates)
sites <- data.frame(read.csv(?/your/path/to/pointfile.csv?))
#Now make the map
ggplot(data=df, aes(y=Latitude, x=Longitude)) +
geom_raster(aes(fill=MAP)) +
geom_point(data=sites, aes(x=x, y=y), color=?white?, size=3, shape=4) +
theme_bw() +
coord_equal() +
scale_fill_gradient(?MAP (mm/yr)?, limits=c(0,2500)) +
theme(axis.title.x = element_text(size=16),
axis.title.y = element_text(size=16, angle=90),
axis.text.x = element_text(size=14),
axis.text.y = element_text(size=14),
panel.grid.major = element_blank(),
panel.grid.minor = element_blank(),
legend.position = ?right?,
legend.key = element_blank()
)
(oo)
--oOO--( )--OOo----------------
Stefano Sofia PhD
Area Meteorologica e Area nivologica - Centro Funzionale
Servizio Protezione Civile - Regione Marche
Via del Colle Ameno 5
60126 Torrette di Ancona, Ancona
Uff: 071 806 7743
E-mail: stefano.sofia at regione.marche.it
---Oo---------oO----------------
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Hi, You might get more help from the R-sig-geo list, which is devoted to spatial topics. However. The *.asc file is an ArcGIS raster export format. You should use whatever the appropriate import commands are for your own gridded rainfall data. If you have a different format, you might or might not be able to import it directly with raster. ?raster will tell you more about the kinds of formats that function can handle importing. I'm not sure what the intent of converting a raster to point data actually is; if you have point data, then import it as point data. If you have gridded data, then map it as gridded data. But if it makes sense to you, then go for it. The comments in your code sample explain what the CSV file should be: coordinates of the points to be mapped. I'm not even certain from your question what your objective is. What kind of rainfall data are you starting with? What kind of maps do you want to produce? Sarah On Fri, Nov 17, 2017 at 3:40 AM, Stefano Sofia <stefano.sofia at regione.marche.it> wrote:> Dear R users, > I need to produce rainfall maps using R. > I know that this is possible, I looked though the web, I found the example below reported (the author is Andrew Tredennick). > I would ask you if this is the most performing way to make rainfall maps; if yes would someone be able to give me an example of how file.asc and pointfile.csv should be? If no would somebody please show me another way providing a small example? > > Thank you for your help > Stefano > > > library(raster) > library(ggplot2) > > #open ASCII file using ?raster? command, which converts the ASCII to a raster object > map <- raster(?/your/path/to/file.asc?) > > #convert the raster to points for plotting > map.p <- rasterToPoints(map) > > #Make the points a dataframe for ggplot > df <- data.frame(map.p) > #Make appropriate column headings > colnames(df) <- c(?Longitude?, ?Latitude?, ?MAP?) > > #Call in point data, in this case a fake transect (csv file with lat and lon coordinates) > sites <- data.frame(read.csv(?/your/path/to/pointfile.csv?)) > > #Now make the map > ggplot(data=df, aes(y=Latitude, x=Longitude)) + > geom_raster(aes(fill=MAP)) + > geom_point(data=sites, aes(x=x, y=y), color=?white?, size=3, shape=4) + > theme_bw() + > coord_equal() + > scale_fill_gradient(?MAP (mm/yr)?, limits=c(0,2500)) + > theme(axis.title.x = element_text(size=16), > axis.title.y = element_text(size=16, angle=90), > axis.text.x = element_text(size=14), > axis.text.y = element_text(size=14), > panel.grid.major = element_blank(), > panel.grid.minor = element_blank(), > legend.position = ?right?, > legend.key = element_blank() > ) > > > > (oo) > --oOO--( )--OOo---------------- > Stefano Sofia PhD > Area Meteorologica e Area nivologica - Centro Funzionale > Servizio Protezione Civile - Regione Marche > Via del Colle Ameno 5 > 60126 Torrette di Ancona, Ancona > Uff: 071 806 7743 > E-mail: stefano.sofia at regione.marche.it > ---Oo---------oO---------------- >-- Sarah Goslee http://www.functionaldiversity.org
Fwiw the engine behind geom_raster needs explicit observation-per-row form for input (with no structural normalization), so conversion to points is perfectly proper here, albeit confusing in context. (It's closer to what graphics devices actually use ultimately, but the expansion is laid out very early in ggplot2 because there's no standard for intermediate forms.) Cheers, Mike On Wed, 22 Nov 2017, 07:12 Sarah Goslee, <sarah.goslee at gmail.com> wrote:> Hi, > > You might get more help from the R-sig-geo list, which is devoted to > spatial topics. > > However. > > The *.asc file is an ArcGIS raster export format. You should use > whatever the appropriate import commands are for your own gridded > rainfall data. If you have a different format, you might or might not > be able to import it directly with raster. > > ?raster will tell you more about the kinds of formats that function > can handle importing. > > I'm not sure what the intent of converting a raster to point data > actually is; if you have point data, then import it as point data. If > you have gridded data, then map it as gridded data. But if it makes > sense to you, then go for it. > > The comments in your code sample explain what the CSV file should be: > coordinates of the points to be mapped. > > I'm not even certain from your question what your objective is. > > What kind of rainfall data are you starting with? > What kind of maps do you want to produce? > > Sarah > > > > On Fri, Nov 17, 2017 at 3:40 AM, Stefano Sofia > <stefano.sofia at regione.marche.it> wrote: > > Dear R users, > > I need to produce rainfall maps using R. > > I know that this is possible, I looked though the web, I found the > example below reported (the author is Andrew Tredennick). > > I would ask you if this is the most performing way to make rainfall > maps; if yes would someone be able to give me an example of how file.asc > and pointfile.csv should be? If no would somebody please show me another > way providing a small example? > > > > Thank you for your help > > Stefano > > > > > > library(raster) > > library(ggplot2) > > > > #open ASCII file using ?raster? command, which converts the ASCII to a > raster object > > map <- raster(?/your/path/to/file.asc?) > > > > #convert the raster to points for plotting > > map.p <- rasterToPoints(map) > > > > #Make the points a dataframe for ggplot > > df <- data.frame(map.p) > > #Make appropriate column headings > > colnames(df) <- c(?Longitude?, ?Latitude?, ?MAP?) > > > > #Call in point data, in this case a fake transect (csv file with lat and > lon coordinates) > > sites <- data.frame(read.csv(?/your/path/to/pointfile.csv?)) > > > > #Now make the map > > ggplot(data=df, aes(y=Latitude, x=Longitude)) + > > geom_raster(aes(fill=MAP)) + > > geom_point(data=sites, aes(x=x, y=y), color=?white?, size=3, shape=4) + > > theme_bw() + > > coord_equal() + > > scale_fill_gradient(?MAP (mm/yr)?, limits=c(0,2500)) + > > theme(axis.title.x = element_text(size=16), > > axis.title.y = element_text(size=16, angle=90), > > axis.text.x = element_text(size=14), > > axis.text.y = element_text(size=14), > > panel.grid.major = element_blank(), > > panel.grid.minor = element_blank(), > > legend.position = ?right?, > > legend.key = element_blank() > > ) > > > > > > > > (oo) > > --oOO--( )--OOo---------------- > > Stefano Sofia PhD > > Area Meteorologica e Area nivologica - Centro Funzionale > > Servizio Protezione Civile - Regione Marche > > Via del Colle Ameno 5 > > 60126 Torrette di Ancona, Ancona > > Uff: 071 806 7743 > > E-mail: stefano.sofia at regione.marche.it > > ---Oo---------oO---------------- > > > > > -- > Sarah Goslee > http://www.functionaldiversity.org > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.-- Dr. Michael Sumner Software and Database Engineer Australian Antarctic Division 203 Channel Highway Kingston Tasmania 7050 Australia [[alternative HTML version deleted]]