[R] Steps to create spatial plots

[lily li]

Hi Eric,

Thanks, it works. If I want to convert the matrix to the 1-D vector for the
levelplot, should I use the command below? I thought the t() is a reverse
function, but may be not.

values <- layer$z
values.v <- as.vector(t(values))

On Tue, Jan 16, 2018 at 12:36 AM, Eric Berger <ericjberger at gmail.com> wrote:

> If layer$z is a matrix and you want to reverse the order of the rows, you
> can do:
>
> n <- nrow(layer$z)
> layer$z <- layer$z[ n:1, ]
>
> HTH,
> Eric
>
>
> On Tue, Jan 16, 2018 at 8:43 AM, lily li <chocold12 at gmail.com> wrote:
>
>> Sorry for the emails, I just wanted to have an example.
>> layer$z
>>
>> 1  1  3  4  6  2
>> 2  3  4  1  2  9
>> 1  4  5  2  1  8
>>
>> How to convert the matrix to layer$z = c(1, 4, 5, 2, 1, 8, 2, 3, 4, 1, 2,
>> 9, 1, 1, 3, 4, 6, 2)?
>> I think this vector is the order that levelplot can use. Thanks again.
>>
>>
>> On Mon, Jan 15, 2018 at 10:58 PM, lily li <chocold12 at gmail.com> wrote:
>>
>> > Hi Bert,
>> >
>> > I think you are correct that I can use levelplot, but I have a question
>> > about converting data. For example, the statement:
>> > levelplot(Z~X*Y), Z is row-wise from the lower left corner to the upper
>> > right corner.
>> > My dataset just have gridded Z data as a txt file (or can be called
>> > matrix?), how to convert them to the vector in order for levelplot to
>> use?
>> > Thanks.
>> >
>> > On Mon, Jan 15, 2018 at 6:04 PM, Bert Gunter <bgunter.4567 at gmail.com>
>> > wrote:
>> >
>> >> From your description, I am **guessing** that you may not want a
>> "spatial
>> >> map" (including projections) at all, but rather something like a level
>> >> plot. See ?levelplot in the lattice package for details. Both I am sure
>> >> ggplot2 has something similar.
>> >>
>> >> Apologies if I havemisunderstood your intent/specifications.
>> >>
>> >> Cheers,
>> >> Bert
>> >>
>> >>
>> >> Bert Gunter
>> >>
>> >> "The trouble with having an open mind is that people keep coming along
>> >> and sticking things into it."
>> >> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>> >>
>> >> On Mon, Jan 15, 2018 at 4:54 PM, lily li <chocold12 at gmail.com> wrote:
>> >>
>> >>> Hi Roman,
>> >>>
>> >>> Thanks for your reply. For the spatial coordinates layer, I just have
>> >>> coordinates of the upper left corner, numbers of rows and columns of
>> the
>> >>> spatial map, and grid cell size. How to create a spatial layer of
>> >>> coordinates from this data? Thanks.
>> >>>
>> >>>
>> >>> On Mon, Jan 15, 2018 at 3:26 PM, Roman Luštrik <
>> roman.lustrik at gmail.com>
>> >>> wrote:
>> >>>
>> >>> > You will need to coerce your data into a "spatial" kind, as
>> >>> implemented in
>> >>> > `sp` or as of late, `sf` packages. You might want to give the
>> >>> vignettes a
>> >>> > whirl before you proceed.
>> >>> > Roughly, you will have to coerce the data to Spatial* (you could go
>> >>> for a
>> >>> > point, raster or grid type, I think) and also specify the
>> projection.
>> >>> Once
>> >>> > you have that, plotting should be handled by packages.
>> >>> >
>> >>> > Here are a few quick links that might come handy:
>> >>> >
>> >>> > https://cran.r-project.org/web/views/Spatial.html
>> >>> > http://www.datacarpentry.org/R-spatial-raster-vector-
>> >>> > lesson/10-vector-csv-to-shapefile-in-r/
>> >>> >
>> >>> >
>> >>> > Cheers,
>> >>> > Roman
>> >>> >
>> >>> > On Mon, Jan 15, 2018 at 11:22 PM, lily li <chocold12 at gmail.com>
>> wrote:
>> >>> >
>> >>> >> Hi users,
>> >>> >>
>> >>> >> I have no clear clue about plotting spatial data. For example, I
>> just
>> >>> >> have a table with attribute values of each grid cell, such as
>> >>> elevation.
>> >>> >> Then I have coordinates of the upper left corner in UTM, the number
>> >>> of rows
>> >>> >> and columns, and grid cell size. How to create spatial plot of
>> >>> elevations
>> >>> >> for the grid cells, in color ramp? Should I create a spatial grid
>> >>> layer
>> >>> >> with all the polygons first? Thanks.
>> >>> >>
>> >>> >> --
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>> >>> >
>> >>> >
>> >>> > --
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