Message Standardization

In order to reduce the amount of similar strings please use standardized messages. This helps with message translation as well.

How should Errors/Warnings/Messages be formatted

  • Only user derived variables should be bracketed, not GRASS derived variables, for example:
     Yes: Creating raster map <%s>.  Pass 1 of 7 ...
     No:  Creating <raster> map <%s>.  Pass [1] of [7] ...
  • strings < > - raster, vector maps, group names, etc., e.g.
    • Raster map <%s> not found
  • strings ' ' - paths, SQL queries, etc., e.g.
    • File '%s' not found
    • Unable to create table: '%s'


  • The [bracketed] parenthetical disrupts the flow of the phrase and doesn't help enhance clarity of meaning. IMHO, this reads better without [] brackets: "Line %d deleted." [] Brackets should be used when value is outside of the phrase: "Unknown line [%d]". --HB


symbol number of code lines (2007-04-11) 2008-02-14 (6.3svn) 2009-08-02 (7.0svn) 2013-06-21 (7.0svn)
<%s> 637 1406 1935 2398
[%s] 690 427 222 189
'%s' 354 370 537 689
<%d> 12 7 11 18
[%d] 207 13 137 136
'%d' 3 1 1 3
TYPES="<%s> \[%s\] '%s' <%d> \[%d\] '%d'"

for TYPE in $TYPES ; do
  NUM_HITS=`grep -rI "$TYPE" * | grep -v '/.svn/\|^dist.i686-\|locale/po/' | wc -l`
  echo "$TYPE  $NUM_HITS"

Macros to be defined for C library

  • MSG_RASTER_NOT_FOUND_IN_MAPSET - "Raster map <%s> not found in <%s>"
  • MSG_CANNOT_OPEN_RASTER - "Unable to open raster map <%s>"
  • MSG_CANNOT_OPEN_FILE - Unable to open file <%s>

Note: Problem with xgettext package. How to use macros to work with xgettext?

Standard messages sandbox

  • First letter should be capitalized
  • Use the present tense
    (cannot instead of could not; better: unable to; even better: avoid the issue altogether by rewording like "File not found.")
  • Avoid contractions (cannot instead of can't)
  • Good sentence construction
    ("Cannot find input map <%s>" instead of "It could not be find input map <%s>"; possibly better: "Input map <%s> not found.")
  • Be consistent with periods. Either end all phrases with a period or none. Without periods the translators save also some time
    Complete sentences or all parts of a message with multiple sentences should end with periods. Short phrases should not. Punctuated events, such as errors, deserve a period. e.g. "Operation complete." Phrases which imply ongoing action look odd if missing an ellipse or any other form of punctuation. Phrase != Sentence. --HB
  • Either all module descriptions should end with periods or not. As some are multi-sentence, and thus should end in a period for consistency within the message, so probably they all should end in one. Currently by my count 237 end with '.', 139 do not. In the multi-sentence case it may be posible to put the simple description in the module->label field and additional explanitory text into the ->description field.
  • option and flag descriptions generally should not end in a period (more likely to be phrases than sentences). But they can suffer the same multi-sentence period problem as module descriptions. In this case splitting out additional text into a ->label, ->description split may help.
  • Suspension points used to indicate some process is being done should be placed next to last word, without space. e.g.
    Reading raster map...
    instead of
    Reading raster map ...
    HB: FWIW & my 2c, 1) to me keeping the space before the ellipse looks better, is this a purely cosmetic choice or is there some style logic? [wikipedia article on the ellipse was cited on grass-dev, I would argue that refers to printed typeset text not monospace terminal text, strangely suggests punctuation+3 dots (....), is just one other guy's opinion, and I'm still not swayed] 2) these messages may be good candidates for G_verbose_message().
    HB 2c more: (i.landsat.rgb example)
      Processing <$i>...
      Processing <$i> ...
    The version with the space just looks better. The version without just looks wrong. But when the line ends with a word, no-space doesn't look that bad: (
      Importing points...
      Importing points ...
  • Module descriptions should use all the same verbal tense. Currently some of them can be found in infinitive and others in present.

DB messages

db_open_database(), db_start_driver_open_database()

Unable to open database <%s> by driver <%s>


Unable to insert new record: '%s'

Unable to create table: '%s'

Unable to drop table: '%s'


Unable to grant privileges on table <%s>


Unable to start driver <%s>


Unable to describe table <%s>


Unable to select record from table <%s> (key %s, column %s)

No records selected from table <%s>


Unable to fetch data from table <%s>

db_create_index(), db_create_index2()

Unable to create index for table <%s>, key <%s>

db_copy_table(), db_copy_table_by_ints()

Unable to copy table <%s>


Unable to delete table <%s>


Unable to find table <%s> linked to vector map <%s>


Column <%s> not found in table <%s>


Unable to get list tables in database <%s>


Unable to open select cursor: '%s'


Unable to create table <%s>


Unable select records from table <%s>

General messages


<%s> is an illegal file name


Invalid graphics coordinates

Unable to set region


Error calculating graphics-region conversions


Unable to open temporary file <%s>


Unable to get projection info of raster map


Unable to get projection units of raster map

Raster messages


Raster map <%s> not found

Raster map <%s> not found in the current mapset

Raster map <%s> not found in mapset <%s>

Rast_open_old() [in GRASS 6: G_open_cell_old()]

Unable to open raster map <%s>

Rats_open_new [in GRASS 6: G_open_cell_new()]

Unable to create raster map <%s>

Rast_close() [in GRASS 6: G_close_cell()]

Unable to close raster map <%s>

Rast_get_cellhd() [in GRASS 6: G_get_cellhd()]

Unable to read header of raster map <%s>

Rast_get_row() [in GRASS 6: G_get_raster_row()]

Unable to read raster map <%s> row %d

Rast_put_row() [in GRASS 6: G_put_raster_row()]

Failed writing raster map <%s> row %d

Rast_write_cats [in GRASS 6: G_write_cats()]

Unable to write category file for raster map <%s>

Rast_read_colors() [in GRASS 6: G_read_colors()]

Unable to read color file of raster map <%s>

Rast_read_cats() [in GRASS 6: G_read_cats()]

Unable to read category file of raster map <%s>

Rast_fp_range() [in GRASS 6: G_read_fp_range()]

Unable to read fp range of raster map <%s>

Rast_read_range() [in GRASS 6: G_read_range()]

Unable to read range of raster map <%s>

3D raster messages


3D raster map <%s> not found

3D raster map <%s> not found in the current mapset

3D raster map <%s> not found in mapset <%s>


Unable to open 3D raster map <%s>


Unable to read range of 3D raster map <%s>


Unable to close 3D raster map <%s>

Vector messages


Vector map <%s> not found

Vector map <%s> not found in the current mapset

Vector map <%s> not found in mapset <%s>


Unable to open vector map <%s>

Unable to open vector map <%s> at topology level %d


Unable to create vector map <%s>

Vect_get_field(), Vect_get_dblink()

Database connection not defined for layer %d


Area %d without centroid or Skipping area %d without centroid


Unable to open header file of vector map <%s>


Unable to add database link for vector map <%s>


Unable to read vector map <%s> feature id %d


  • "Map <roads> in <user1>" or "Map <roads@user1>"
    • "Map <roads@user1>" preferred - [[User:Landa|ML]]
    • If the element was given on the command line, the user knows which mapset it came from, and the @mapset part is just extra noise. If the element is taken from the data (how? where the user hasn't explicitly defined the map, then @mapset it appropriate. Also output maps are always created in the current mapset* so @mapset is redundant and should not be used for new maps. [* i.rectify,, are exceptions that can create maps in other mapsets or new locations] --HB

Proposed standard responses in bold.

  • G_get_raster_row()
    "Unable to read raster map <%s> row %d"
    Cannot get raster raster of input map
    Cannot raster raster of input map
    Cannot read raster row [%d]
    can't read row in input elevation map
    Could not read from <%s>
    Could not read from <%s>, row=%d
    Error getting input null cells
    error reading hue data
    Error reading 'hue' map
    Error reading input
    error reading intensity data
    Error reading 'intensity' map
    Error reading map %s
    Error reading row of data
    error reading saturation data
    Error reading 'saturation' map
    G_get_raster_row failed
    reading map
    Reading map
    Reading row %d
    read_row: error reading data
    %s: Unable to read raster map [%s]
    Unable to get row %d from raster map
    Unable to get row %d from <%s>
    Unable to read map raster row %d
    Unable to read raster row.
    Unable to read raster row %d
    Unable to read row %i\n
  • G_put_raster_row()
    "Failed writing raster map <%s> row %d"
    Cannot write row to raster map
    Cannot write to <%s>
    Error while writing new cell map.
    Error writing cell map during transform.
    error writing data
    Error writing output map
    G_put_raster_row failed (file system full?)
    %s - ERROR writing %s
    Unable to properly write output raster map
    unable to write map row %d
  • G_open_cell_new()
    "Unable to create raster map <%s>"
    Cannot open output raster map <%s>
    can't open %s
    Error in opening output file <%s>
    Unable to create output <%s>
    Unable to create raster map <%s>
    Unable to create raster map [%s]
    Unable to open cell map <%s> for output.\n
    Unable to open output file.
    Unable to open the cell map MASK.
  • G_open_cell_old()
    "Unable to open raster map <%s>"
    Cannot find map %s
    Cannot find mapset for %s
    Cannot open File %s
    Cannot open input raster map <%s>
    Cannot open map %s
    Cannot open raster map
    Cannot open raster map <%s>
    Cannot open raster map [%s]
    Cannot open raster map [%s]!
    Cannot open %s
    Cannot open seed map <%s@%s>!
    Cannot open terrain raster map <%s@%s>!
    Can't open input map
    can't open raster map [%s]
    can't open raster map <%s> in mapset %s
    can't open %s
    Could not open raster <%s>
    Could not open raster '%s'
    Error in opening input file <%s>
    Not able to open cellfile for [%s]
    Problem opening input file [%s]
    Raster file <%s> not found
    Raster map [%s] not found  
    <%s> cellfile not found
    %s: Couldn't open raster <%s@%s>
    %s: o_open_file: could not open raster map %s in %s
    Unable to open band files.
    Unable to open cellfile for [%s]
    Unable to open map <%s>
    Unable to open MASK
    Unable to open raster map [%s]
    Unable to open raster <%s>
    unable to open [%s] in [%s]
    Unable to proceed
  • G_find_raster()
    "Raster map <%s> not found"
    albedo raster map <%s> not found
    aspin raster map <%s> not found
    Cannot find map %s
    Cannot find mapset for %s
    Cannot find raster map
    Cannot find %s
    cell file [%s] not found
    coefbh raster map <%s> not found
    elevin raster map <%s> not found
    Input map [%s] in location [%s] in mapset [%s] not found.
    latin raster map <%s> not found
    linkein raster map <%s> not found
    No clump map specified and MASK not set.
    Raster file [%s] not found. Exiting.
    Raster map [%s] already exists.\nPlease try another.
    Raster map <%s> not found
    Raster map [%s] not found
    Raster <%s> already exist.
    Raster <%s> not found
    Raster '%s' not found
    Requested raster map <%s> not found
    [%s] cannot be found!
    %s - exits in Mapset <%s>, select another name
    slopein raster map <%s> not found
    %s: more than %d files not allowed
    %s - not found
    %s: o_open_file: raster map %s not found
    %s: <%s> raster map not found
    %s: %s - raster map not found
    %s: %s - Unable to find the imaginary-image.
    %s: %s - Unable to find the real-image map.
    Training map [%s] not found.
    Unable to find base map <%s>
    Unable to find cell map <%s>
    Unable to find cover map <%s>
    Unable to find file [%s].
    Unable to find input cell map <%s>
  • G_find_raster2()
    "Raster map <%s> not found"
    Raster map <%s> not found in current mapset
    Raster map <%s> not found
    Raster file [%s] not found. Exiting.
  • G_find_vector()
    "Vector map <%s> not found"
    Cannot find vector map
    Could not find input map <%s>
    Could not find input map <%s>.
    Could not find input map '%s'.
    Could not find input map <%s> in current mapset.
    Could not find input map <%s>\n
    Could not find input %s
    Could not find input %s\n
    Could not find input vector map <%s>
    Could not find input vector map %s
    Could not find network input map '%s'.
    Could not find vector map <%s> in current mapset
  • G_tempfile()
    "Unable to open temporary file <%s>"
    Unable to write the temporary file   
    Unable to open temp file.            
    Unable to open tempfile              
    Unable to open temporary file <%s> 

Systematic Approach

  • Collect all possible error states from functions
  • assign error codes for macros?
  • G_option() parameters (like output->description = ("Path to resulting ASCII file");)

Note: Would be possible to conctretize your ideas? (MartinL)

Parameters and flags

Fix the parameters and flags. Make it a concept. See proposal(s)

Verbosity levels

Current abstract concept

type GRASS_VERBOSE libgis command line result libgis fn
verbose 3 MAX_LEVEL --verbose print progress and all messages messages G_verbose_message()
standard 2 STD_LEVEL print progress and selected messages G_message()
brief 1 print only progress information (% done) G_percent(), G_clicker(), G_important_message()
quiet 0 MIN_LEVEL --quiet print nothing (only ERRORs and WARNINGs) G_warning(), G_fatal_error()
debug 0-5 print debug message at DEBUG level set with g.gisenv G_debug(#, "")
mute - 2>&1 > /dev/null only for use in rare occasions


  • module output (should be &quot;parsable&quot;) is not controlled by GRASS_VERBOSE [use fprintf (stdout, ...)]
  • quiet
    only warnings and fatal errors are printed
  • brief
    all G_percent() and G_important_message() (especially connected to progress information??)
  • standard
    all G_percent() and selected G_message()
  • verbose
    all G_percent() + G_message() + G_verbose_message()


  • remove verbose level &rarr; standard == all G_percent () + G_messages()
    why?? --HB
  • remove "--verbose" from help pages, manually mention where it does work.
    it only does something in a few modules
  • move some messages to G_debug()
  • move some messages to G_verbose_message()
  • move some messages to G_important_message()
  • change level numbers to 1, 3, 5
  • Add new G_msg(int level, "%format", ...); lib function. Existing G_message() could stay and would be the same as G_msg(LEVEL_STD,...).


  • HB: I'm quite happy to leave the current system as it is, but use GRASS_MESSAGE_FORMAT=silent to switch off G_percent(),G_clicker() output.
    Mixing a sliding verbosity scale plus a binary switch or >= rule for when G_percent() happens in the same variable is very messy IMO.

Alternative abstract concept

(Binary method, 3=1+2)

How to deal with --verbose messages? add levels 4 (vmsg+msg) and 5(vmsg+msg+progress) ?

standard 3 PERMSG_MODE print progress and messages
standard 2 MESSAGE_MODE print only messages
brief 1 PERCENT_MODE print only progress information
silent but not mute 0 QUIET_MODE print nothing (but ERR and WAR)
mute 2>&1 > /dev/null
Last modified 5 years ago Last modified on Mar 24, 2018, 3:58:39 AM
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