In R and knitr, can I suppress the message of readOGR?

Question

I'm building small report using R & knitr, sending the output to pdf.

I'm using several shape files in my analysis and whenever I use readOGR function of rgdal package I get information on what is being read, for instance:

OGR data source with driver: ESRI Shapefile 
Source: "__PATH_HERE__", layer: "__NAME__OF__LAYER__HERE__"
with 148 features and 5 fields
Feature type: wkbPolygon with 2 dimensions

Normally, it's useful thing to have.. but unfortunately it also prints out in my pdf output.

I tried setting knitr's chunk options to echo=FALSE, message=FALSE but unfortunately it did't help.

Any better solution to that?

you got two better solutions, but when everything else fails (ie print message in C code, and knitr chunk that you want to see other output from), I found that `capture.output` can be useful. — baptiste, Apr 15 '13 at 10:41

score 30 · Accepted Answer · edited Apr 15 '13 at 10:45

30

Have you tried setting verbose = FALSE in the readOGR function itself?

e.g.

> dsn <- system.file("vectors", package = "rgdal")[1]
> cities <- readOGR(dsn=dsn, layer="cities")
OGR data source with driver: ESRI Shapefile 
Source: "C:/Users/sohanlon/Dropbox/R/R64_Win_Libs/rgdal/vectors", layer: "cities"
with 606 features and 4 fields
Feature type: wkbPoint with 2 dimensions
# Set verbose = FALSE
> cities <- readOGR(dsn=dsn, layer="cities" , verbose = FALSE)

The relevant knitr chunk, then, could be:

```{r, echo=FALSE, message=FALSE}
library(rgdal)
dsn <- system.file("vectors", package = "rgdal")[1]
cities <- readOGR(dsn=dsn, layer="cities", verbose=FALSE)
```

edited Apr 15 '13 at 10:45

A5C1D2H2I1M1N2O1R2T1

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answered Apr 15 '13 at 10:25

Simon O'Hanlon

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+1 for `verbose = FALSE`. I like `results = "hide"` because it is a bit more transparent. – A5C1D2H2I1M1N2O1R2T1 Apr 15 '13 at 10:45
@SimonO101 Doh. I didn’t realize I should be looking at solution on readOGR side. All working now. Thanks. – radek Apr 15 '13 at 11:15
For reference, in `sf` use `quiet = TRUE` – B. Davis Jan 10 '19 at 22:30

score 9 · Answer 2 · answered Apr 15 '13 at 10:31

9

The "knitr" way to do this would be to use results = 'hide'. Borrowing from @SimonO101's example data, try:

```{r, results='hide', echo=FALSE, message=FALSE}
library(rgdal)
dsn <- system.file("vectors", package = "rgdal")[1]
cities <- readOGR(dsn=dsn, layer="cities")
```

answered Apr 15 '13 at 10:31

A5C1D2H2I1M1N2O1R2T1

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Does that hide the actual commands too? Which might be what the OP wants of course. – Simon O'Hanlon Apr 15 '13 at 10:34
@SimonO101, Sure. But then then just change it to `echo=TRUE` to see the code that was entered. – A5C1D2H2I1M1N2O1R2T1 Apr 15 '13 at 10:36
Ah cool. Getting better with `knitr` is on my to do list. It's funny how everything moves ON to my to do list, but never seems to move OFF it. +1 for the knitr way. – Simon O'Hanlon Apr 15 '13 at 10:37
Thanks - I like that results = "hide" still lets me see my images/maps in the final documnent. – Nova Jun 26 '18 at 14:42

In R and knitr, can I suppress the message of readOGR?

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