Issues with multiple label blocks and symbols

[woodbri]

I'm trying to convert my roads layer from a LINE (for stlying the roads and labeling them) and ANNOTATION (for placing hwy shields) into a single LINE layer with with multiple label blocks.

It seems close to working except that the symbols for the shields are not getting rendered. The text for the shields is rendered by not the symbols.

​http://imaptools.com:8080/demo/tiger2011.html?zoom=10&lat=34.77041&lon=-92.22651&layers=00B0

The layer looks like this:

    LAYER
        NAME "roads"
        METADATA
            "ows_title"     "Roadway features"
            "ows_srs"       "EPSG:4269 EPSG:4326"
            "ows_abstract"  "Road way features from the U.S. Census ROADS data layer."
        END
        TYPE LINE
        TILEINDEX "tidx-ROADS"
        PROJECTION
            "+proj=longlat +ellps=GRS80 +datum=NAD83" #EPSG: 4269
        END
        INCLUDE "map-ROADS.inc"
    END

And the include looks like:

  MAXSCALEDENOM 500000
  CLASSITEM "RTTYP"
  LABELITEM "FULLNAME"
  SIZEUNITS METERS
  CLASS
    EXPRESSION ('[MTFCC]' = 'S1100')
    STYLE
      COLOR "#FFC95B"
      WIDTH 20
      MAXWIDTH 16
      OUTLINECOLOR "#E9B352"
      OUTLINEWIDTH 1.5
    END
    LABEL
      MAXSCALEDENOM 300000
      TYPE TRUETYPE
      FONT "arial"
      SIZE 18
      MAXSIZE 10
      MINSIZE 8
      COLOR "#3C0800"
      OUTLINECOLOR "#FFC95B"
      PARTIALS FALSE
      MINDISTANCE 250
      MINFEATURESIZE 10
      BUFFER 4
      ANGLE FOLLOW
      PRIORITY 4
    END
    LABEL
      MAXSCALEDENOM 300000
      EXPRESSION ('[RTTYP]' = 'I' && '[RTENUM]' ~ '.')
      TEXT '[RTENUM]'
      STYLE
        #GEOMTRANSFORM 'labelpnt'
        SYMBOL "I"
      END
      SIZE TINY
      POSITION CC
      OFFSET 1 0
      MINDISTANCE 100
      COLOR "#ffffff"
      PARTIALS FALSE
      PRIORITY 7
    END
    LABEL
      MAXSCALEDENOM 300000
      EXPRESSION ('[RTTYP]' = 'U' && '[RTENUM]' ~ '.')
      TEXT '[RTENUM]'
      STYLE
        #GEOMTRANSFORM 'labelpnt'
        SYMBOL "U"
      END
      SIZE TINY
      POSITION CC
      OFFSET 1 0
      MINDISTANCE 100
      COLOR "#ffffff"
      PARTIALS FALSE
      PRIORITY 7
    END
  END

and more classes using the same patterns as above. I have tried with and without the GEOMTRANSFORM 'labelpnt'

At 433K scaledenom and larger I have another layer with generalized data and only one label block per class and it displays the shields correctly.

​http://imaptools.com:8080/demo/tiger2011.html?zoom=9&lat=34.77041&lon=-92.22651&layers=00B0

This layer looks like:

    LAYER
        NAME "pri_sec_roads"
        METADATA
            "ows_title"     "Primary and Secondary Roadway features"
            "ows_srs"       "EPSG:4269 EPSG:4326"
            "ows_abstract"  "Primary and Secondary Roadway features from the U.S. Census PRISECROADS data layer."
        END
        TYPE LINE
        TILEINDEX "tidx-PRISECROADS-S"
        #DATA "PRISECROADS-S/tl_2011_17_prisecroads.shp"
        PROJECTION
            "+proj=longlat +ellps=GRS80 +datum=NAD83" #EPSG: 4269
        END
        INCLUDE "map-PRISECROADS.inc"
    END

and the include follows:

  LABELITEM "RTENUM"
  CLASS
    MAXSCALEDENOM 5000000
    MINSCALEDENOM  300000
    EXPRESSION ('[RTTYP]' = 'I')
    STYLE
      COLOR "#FFC95B"
      WIDTH 1.5
      OUTLINECOLOR "#E9B352"
      OUTLINEWIDTH 0.5
    END
    LABEL
      STYLE
        SYMBOL "I"
      END
      SIZE TINY
      POSITION CC
      OFFSET 1 0
      MINDISTANCE 100
      COLOR "#ffffff"
      PARTIALS FALSE
      PRIORITY 7
    END
  END
  CLASS
    MAXSCALEDENOM 5000000
    MINSCALEDENOM  300000
    EXPRESSION ('[RTTYP]' = 'U' && '[MTFCC]'='S1100')
    STYLE
      COLOR "#F3E999"
      WIDTH 0.5
      OUTLINECOLOR "#ECD390"
      OUTLINEWIDTH 0.5
    END
    LABEL
      STYLE
        SYMBOL "U"
      END
      SIZE TINY
      POSITION CC
      OFFSET 1 0
      MINDISTANCE 100
      COLOR "#000000"
      PARTIALS FALSE
      PRIORITY 7
    END
  END
  CLASS
    MAXSCALEDENOM 5000000
    MINSCALEDENOM  300000
    EXPRESSION ('[RTTYP]' = 'U')
    STYLE
      COLOR "#F3E999"
      WIDTH 0.5
      OUTLINECOLOR "#ECD390"
      OUTLINEWIDTH 0.5
    END
  END
  CLASS
    MAXSCALEDENOM 1000000
    MINSCALEDENOM  300000
    EXPRESSION ('[MTFCC]' = 'S1100')
    STYLE
      COLOR "#FFC95B"
      WIDTH 1.5
      OUTLINECOLOR "#E9B352"
      OUTLINEWIDTH 0.5
    END
  END
  CLASS
    MAXSCALEDENOM 1000000
    MINSCALEDENOM  300000
    EXPRESSION ('[MTFCC]' = 'S1200')
    STYLE
      COLOR "#FFFB89"
      WIDTH 0.75
      OUTLINECOLOR "#ECD390"
      OUTLINEWIDTH 0.5
    END
  END

[tbonfort]

Not a solution, but a couple of notes:

The line drawing code does not call msAddLabelGroup, but msAddLabel repeatedly for each label.

Labels that are status OFF are added which seems definitely wrong. Not sure what to do here as ANGLe FOLLOW labels (and by extent line layers) have a different treatment in msDrawLabelCache(). SteveL, maybe msDrawLabelCache should be reworked so that we don't treat FOLLOW labels differently than regular ones, therefore always calling addLabelGroup() and not addLabel() from msDrawShape()?

[tbonfort]

SteveW, can you try this patch ?

Index: maplabel.c
===================================================================
--- maplabel.c	(revision 13231)
+++ maplabel.c	(working copy)
@@ -486,7 +486,7 @@
   classObj *classPtr=NULL;
 
   if(!label) return(MS_FAILURE); // RFC 77 TODO: set a proper message
-  if(!label->annotext) return(MS_SUCCESS); /* not an error */ 
+  if(!label->annotext || label->status == MS_OFF) return(MS_SUCCESS); /* not an error */ 
 
   layerPtr = (GET_LAYER(map, layerindex)); /* set up a few pointers for clarity */
   classPtr = GET_LAYER(map, layerindex)->class[classindex];

[woodbri]

Ok, the patch appears to already be checked into r13239.

So regarding a mix of labels like ANGLE FOLLOW and additional highway shields, I'm not sure I follow the discussion of grouped labels and ungrouped labels. It would seem to me that we might want shields to be grouped but the ANGLE FOLLOWs not part of the group.

I also do not understand how potential label points are generated when you have something like FOLLOW and shields because you obviously want to look for additional label points that are not occupied by the previous label. But maybe that is already part of the logic.

So is the problem that the shield symbol and the text are going at the same point and one is bumping off the other because addLabel is getting drawn instead of addLabelGroup?

[tbonfort]

Replying to woodbri:

So is the problem that the shield symbol and the text are going at the same point and one is bumping off the other because addLabel is getting drawn instead of addLabelGroup?

Yes, this is very probable. The use-case we were targetting with multiple labels did not concern line labelling, and I suspect Steve didn't look into it during implementation.

[woodbri]

Ok, I can understand that, but what is confusing to me is why is the shield text drawn, but not the shield?

    LABEL
      MAXSCALEDENOM 300000
      EXPRESSION ('[RTTYP]' = 'U' && '[RTENUM]' ~ '.')
      TEXT '[RTENUM]'
      STYLE
        #GEOMTRANSFORM 'labelpnt'
        SYMBOL "U"
      END
      SIZE TINY
      POSITION CC
      OFFSET 1 0
      MINDISTANCE 100
      COLOR "#ffffff"
      PARTIALS FALSE
      PRIORITY 7
    END

So it is obviously processing this label block because the text is getting rendered but the style with the symbol is not getting rendered. So I guess your thought is that this is the difference between addLabel and addLabelGroup? I just seems that if we are processing a label block it should consider all the tags or explicitly error out on some invalid collection of incompatible tags.

I can see that there maybe a need to enhance multiple labels for line labeling especially if we need to generate additional potential label points.

[woodbri]

Ha! the shields are there, they are just very tiny! I zoomed in to here and found:

​http://imaptools.com:8080/demo/tiger2011.html?zoom=16&lat=34.76138&lon=-92.26222&layers=00B0

if you zoom out one you can see tiny blotches that are the shields. So it seems that because I used SIZEUNITS METERS on the ROADS layer and PIXELS on the ANNOTATION layer that I need to fiddle with MINSIZE and MAXSIZE to fix the SYMBOL size. The text didn't scale because it is fixed at SIZE TINY.

[tbonfort]

Ha! I personally gave up on using sizeunits for this kind of cartographic output, as whereas they are an easy way to get things rolling fast for different scales, they make it nearly impossible to precisely play on font sizes, symbol sizes and offsets, etc...

I would probably start using them again if we had a finer grained control on where they are applied, e.g.

  STYLE
   WIDTH 5 meters
   OFFSET 2 pixels
  END

[woodbri]

I would love to see that as an enhancement. Meanwhile MINSIZE and MAXSIZE are always in pixels so you can add them to override the size units. It is a tough trade off, if I setup scale dependent classes versus scalable features like roads it can double or quadruple the size of the mapfile which makes if difficult to edit and keep everything in sync with one another.

[woodbri]

I have fixed the symbols using MINSIZE and MAXSIZE, but there is a problems with OUTLINEWIDTH scaling on the state shields.

​http://imaptools.com:8080/demo/tiger2011.html?zoom=14&lat=34.7514&lon=-92.2684&layers=00B0

Notice the circle shield in the center and zoom in on it and you will see the outline width scale. This is problematic from a couple of points of view.

1. I can work around it by changing the symbol to a pixmap image.
2. My next iteration on this mapfile is to convert all the pixmap symbols to SVG symbols and I'm not sure how the scaling will impact them.

As noted above, finer grain control on units would solve this issue.

Here is the CLASS definition for the state shield in the URL above.

  CLASS
    EXPRESSION /^[USC]/
    STYLE
      COLOR "#FFFB89"
      WIDTH 18
      OUTLINECOLOR "#ECD390"
      OUTLINEWIDTH 1
    END
    LABEL
      MAXSCALEDENOM 200000
      TYPE TRUETYPE
      FONT "arial"
      SIZE 16
      MAXSIZE 10
      MINSIZE 8
      COLOR "#816C34"
      OUTLINECOLOR "#FFFB89"
      PARTIALS FALSE
      MINDISTANCE 250
      MINFEATURESIZE 10
      BUFFER 4
      ANGLE FOLLOW
      PRIORITY 4
    END
    LABEL
      MAXSCALEDENOM 200000
      EXPRESSION ('[RTTYP]' = 'U' && '[RTENUM]' ~ '.')
      TEXT '[RTENUM]'
      STYLE
        #GEOMTRANSFORM 'labelpnt'
        SYMBOL "U"
        MINSIZE 20
        MAXSIZE 20
      END
      SIZE TINY
      POSITION CC
      OFFSET 1 0
      MINDISTANCE 100
      COLOR "#000000"
      PARTIALS FALSE
      PRIORITY 7
    END
    LABEL
      MAXSCALEDENOM 200000
      EXPRESSION ('[RTTYP]' = 'S' && '[RTENUM]' ~ '.')
      TEXT '[RTENUM]'
      STYLE
        #GEOMTRANSFORM 'labelpnt'
        SYMBOL "circle-filled"
        COLOR "#FFFFFF"
        OUTLINECOLOR "#000000"
#        OUTLINEWIDTH 1   ##### problem is outlinewidth scaling
        MINSIZE 19
        MAXSIZE 19
      END
#      STYLE
#        SYMBOL "circle"
#        COLOR "#000000"
#        MINSIZE 19
#        MAXSIZE 19
#      END
      SIZE TINY
      POSITION CC
      MINDISTANCE 100
      COLOR "#000000"
      PARTIALS FALSE
      PRIORITY 7
    END
  END

[woodbri]

I also tried adding OUTLINEWIDTH and removing the OUTLINECOLOR totally and using a separate STYLE block for the OUTLINE, but it scaled in width also.

[woodbri]

I have created a circle shield for the state hwys as an image so the outline width is constant with the image. Some url as above, look at the circle shield in the center and zoom in/out.

​http://imaptools.com:8080/demo/tiger2011.html?zoom=14&lat=34.7514&lon=-92.2684&layers=00B0

OK, I'm closing this as user error and opening a new ticket for fine grain units support.