How to rescale raster layer in R?
I have a stacked raster layer of a world map that I am trying to rescale from -3.131791 to 3.387701 to 0 to 1. I followed this solution and the first method gives me max(x) = 1 but for some reason min(x) becomes 3.127125e-08. The second method gives me a range of 0 to 1 but when I plot it out my raster layer just becomes a grainy rectangle like this:
.
Here is my code:
## PCA ##
PCA1 <- rasterPCA(img=layers, nComp=1, spca=TRUE)
## Rescale 1 ##
rescale <- function(x, x.min = -3.131791, x.max = 3.387701, new.min = 1, new.max = 0) {
if(is.null(x.min)) {x.min = min(x)}
if(is.null(x.max)) {x.max = max(x)}
new.min + (x - x.min) * ((new.max - new.min) / (x.max - x.min))
}
PCAscaled1 <- calc(PCA1$map[[1]], rescale) #rescaled and inverted
plot(PCAscaled1)
## Rescale 2 ##
r <- PCAscaled1
r <- runif(ncell(PCAscaled1),-3.127125e-08,1)
r.min=cellStats(r,"min")
r.max=cellStats(r,"max")
PCAscaled1a <- (r-r.min)/(r.max-r.min)
plot(PCAscaled1a)
These are the parameters for the original raster in case it's relevant:
> PCA1$map[[1]]
class : RasterLayer
dimensions : 1352, 3570, 4826640 (nrow, ncol, ncell)
resolution : 0.1, 0.1 (x, y)
extent : -177, 180, -56.07567, 79.12433 (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0
data source : /private/var/folders/3c/tsrm9qxs7t323jrz5k8h4d600000gn/T/RtmpKORCX5/raster/r_tmp_2018-11-17_002746_40497_32387.grd
names : PC1
values : -3.131791, 3.387701 (min, max)
I tried to see if any of the individual raster layers I used was the problem, and found out that all but one could be scaled to 0 to 1. But even when I exclude that raster layer I'm still not able to rescale it to 0 to 1. I also tried first rescaling all the individual raster layers then stacking them, but then the range of the stacked raster doesn't stay at 0 to 1 (I then tried to rescale that too but it still doesn't work).
If anyone knows what's wrong I'll really appreciate answers! If there is a different method of rescaling please let me know, I'll try that as well.
r raster
asked Nov 24 '18 at 6:16
toffeetoffee
62
add a comment |
I have a stacked raster layer of a world map that I am trying to rescale from -3.131791 to 3.387701 to 0 to 1. I followed this solution and the first method gives me max(x) = 1 but for some reason min(x) becomes 3.127125e-08. The second method gives me a range of 0 to 1 but when I plot it out my raster layer just becomes a grainy rectangle like this:
.
Here is my code:
## PCA ##
PCA1 <- rasterPCA(img=layers, nComp=1, spca=TRUE)
## Rescale 1 ##
rescale <- function(x, x.min = -3.131791, x.max = 3.387701, new.min = 1, new.max = 0) {
if(is.null(x.min)) {x.min = min(x)}
if(is.null(x.max)) {x.max = max(x)}
new.min + (x - x.min) * ((new.max - new.min) / (x.max - x.min))
}
PCAscaled1 <- calc(PCA1$map[[1]], rescale) #rescaled and inverted
plot(PCAscaled1)
## Rescale 2 ##
r <- PCAscaled1
r <- runif(ncell(PCAscaled1),-3.127125e-08,1)
r.min=cellStats(r,"min")
r.max=cellStats(r,"max")
PCAscaled1a <- (r-r.min)/(r.max-r.min)
plot(PCAscaled1a)
These are the parameters for the original raster in case it's relevant:
> PCA1$map[[1]]
class : RasterLayer
dimensions : 1352, 3570, 4826640 (nrow, ncol, ncell)
resolution : 0.1, 0.1 (x, y)
extent : -177, 180, -56.07567, 79.12433 (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0
data source : /private/var/folders/3c/tsrm9qxs7t323jrz5k8h4d600000gn/T/RtmpKORCX5/raster/r_tmp_2018-11-17_002746_40497_32387.grd
names : PC1
values : -3.131791, 3.387701 (min, max)
I tried to see if any of the individual raster layers I used was the problem, and found out that all but one could be scaled to 0 to 1. But even when I exclude that raster layer I'm still not able to rescale it to 0 to 1. I also tried first rescaling all the individual raster layers then stacking them, but then the range of the stacked raster doesn't stay at 0 to 1 (I then tried to rescale that too but it still doesn't work).
If anyone knows what's wrong I'll really appreciate answers! If there is a different method of rescaling please let me know, I'll try that as well.
r raster
asked Nov 24 '18 at 6:16
toffeetoffee
62
In Funtionrescale, you reversed max and min values:new.minshould be 0, but you define asnew.min=1. Neither donew.max.
– Cobin
Nov 24 '18 at 8:55
Thanks for your comment! This was intentional because I wanted to inverse the raster layer.
– toffee
Nov 25 '18 at 6:45
add a comment |
I have a stacked raster layer of a world map that I am trying to rescale from -3.131791 to 3.387701 to 0 to 1. I followed this solution and the first method gives me max(x) = 1 but for some reason min(x) becomes 3.127125e-08. The second method gives me a range of 0 to 1 but when I plot it out my raster layer just becomes a grainy rectangle like this:
.
Here is my code:
## PCA ##
PCA1 <- rasterPCA(img=layers, nComp=1, spca=TRUE)
## Rescale 1 ##
rescale <- function(x, x.min = -3.131791, x.max = 3.387701, new.min = 1, new.max = 0) {
if(is.null(x.min)) {x.min = min(x)}
if(is.null(x.max)) {x.max = max(x)}
new.min + (x - x.min) * ((new.max - new.min) / (x.max - x.min))
}
PCAscaled1 <- calc(PCA1$map[[1]], rescale) #rescaled and inverted
plot(PCAscaled1)
## Rescale 2 ##
r <- PCAscaled1
r <- runif(ncell(PCAscaled1),-3.127125e-08,1)
r.min=cellStats(r,"min")
r.max=cellStats(r,"max")
PCAscaled1a <- (r-r.min)/(r.max-r.min)
plot(PCAscaled1a)
These are the parameters for the original raster in case it's relevant:
> PCA1$map[[1]]
class : RasterLayer
dimensions : 1352, 3570, 4826640 (nrow, ncol, ncell)
resolution : 0.1, 0.1 (x, y)
extent : -177, 180, -56.07567, 79.12433 (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0
data source : /private/var/folders/3c/tsrm9qxs7t323jrz5k8h4d600000gn/T/RtmpKORCX5/raster/r_tmp_2018-11-17_002746_40497_32387.grd
names : PC1
values : -3.131791, 3.387701 (min, max)
I tried to see if any of the individual raster layers I used was the problem, and found out that all but one could be scaled to 0 to 1. But even when I exclude that raster layer I'm still not able to rescale it to 0 to 1. I also tried first rescaling all the individual raster layers then stacking them, but then the range of the stacked raster doesn't stay at 0 to 1 (I then tried to rescale that too but it still doesn't work).
If anyone knows what's wrong I'll really appreciate answers! If there is a different method of rescaling please let me know, I'll try that as well.
r raster
asked Nov 24 '18 at 6:16
toffeetoffee
62
I have a stacked raster layer of a world map that I am trying to rescale from -3.131791 to 3.387701 to 0 to 1. I followed this solution and the first method gives me max(x) = 1 but for some reason min(x) becomes 3.127125e-08. The second method gives me a range of 0 to 1 but when I plot it out my raster layer just becomes a grainy rectangle like this:
.
Here is my code:
## PCA ##
PCA1 <- rasterPCA(img=layers, nComp=1, spca=TRUE)
## Rescale 1 ##
rescale <- function(x, x.min = -3.131791, x.max = 3.387701, new.min = 1, new.max = 0) {
if(is.null(x.min)) {x.min = min(x)}
if(is.null(x.max)) {x.max = max(x)}
new.min + (x - x.min) * ((new.max - new.min) / (x.max - x.min))
}
PCAscaled1 <- calc(PCA1$map[[1]], rescale) #rescaled and inverted
plot(PCAscaled1)
## Rescale 2 ##
r <- PCAscaled1
r <- runif(ncell(PCAscaled1),-3.127125e-08,1)
r.min=cellStats(r,"min")
r.max=cellStats(r,"max")
PCAscaled1a <- (r-r.min)/(r.max-r.min)
plot(PCAscaled1a)
These are the parameters for the original raster in case it's relevant:
> PCA1$map[[1]]
class : RasterLayer
dimensions : 1352, 3570, 4826640 (nrow, ncol, ncell)
resolution : 0.1, 0.1 (x, y)
extent : -177, 180, -56.07567, 79.12433 (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0
data source : /private/var/folders/3c/tsrm9qxs7t323jrz5k8h4d600000gn/T/RtmpKORCX5/raster/r_tmp_2018-11-17_002746_40497_32387.grd
names : PC1
values : -3.131791, 3.387701 (min, max)
I tried to see if any of the individual raster layers I used was the problem, and found out that all but one could be scaled to 0 to 1. But even when I exclude that raster layer I'm still not able to rescale it to 0 to 1. I also tried first rescaling all the individual raster layers then stacking them, but then the range of the stacked raster doesn't stay at 0 to 1 (I then tried to rescale that too but it still doesn't work).
If anyone knows what's wrong I'll really appreciate answers! If there is a different method of rescaling please let me know, I'll try that as well.
r raster
r raster
asked Nov 24 '18 at 6:16
toffeetoffee
62
asked Nov 24 '18 at 6:16
toffeetoffee
62
edited Nov 26 '18 at 4:10
toffee
asked Nov 24 '18 at 6:16
toffeetoffee
62
asked Nov 24 '18 at 6:16
toffeetoffee
62
asked Nov 24 '18 at 6:16
toffeetoffee
62
62
In Funtionrescale, you reversed max and min values:new.minshould be 0, but you define asnew.min=1. Neither donew.max.
– Cobin
Nov 24 '18 at 8:55
Thanks for your comment! This was intentional because I wanted to inverse the raster layer.
– toffee
Nov 25 '18 at 6:45
add a comment |
In Funtionrescale, you reversed max and min values:new.minshould be 0, but you define asnew.min=1. Neither donew.max.
– Cobin
Nov 24 '18 at 8:55
Thanks for your comment! This was intentional because I wanted to inverse the raster layer.
– toffee
Nov 25 '18 at 6:45
In Funtion
rescale, you reversed max and min values:new.min should be 0, but you define as new.min=1. Neither do new.max.– Cobin
Nov 24 '18 at 8:55
In Funtion
rescale, you reversed max and min values:new.min should be 0, but you define as new.min=1. Neither do new.max.– Cobin
Nov 24 '18 at 8:55
Thanks for your comment! This was intentional because I wanted to inverse the raster layer.
– toffee
Nov 25 '18 at 6:45
Thanks for your comment! This was intentional because I wanted to inverse the raster layer.
– toffee
Nov 25 '18 at 6:45
add a comment |
0
active
oldest
votes
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53455686%2fhow-to-rescale-raster-layer-in-r%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
0
active
oldest
votes
0
active
oldest
votes
active
oldest
votes
active
oldest
votes
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53455686%2fhow-to-rescale-raster-layer-in-r%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
In Funtion
rescale, you reversed max and min values:new.minshould be 0, but you define asnew.min=1. Neither donew.max.– Cobin
Nov 24 '18 at 8:55
Thanks for your comment! This was intentional because I wanted to inverse the raster layer.
– toffee
Nov 25 '18 at 6:45