[mapserver-users] GRID labeling, OK, where are the MapServer
GRID guru's??
Bob Basques
bob.b at gritechnologies.com
Wed Mar 19 10:56:02 EDT 2008
Brent,
Thanks for these notes, exactly the type of stuff we're looking for. I
do remember your thread on the graticules BTW. :c) This is also
something of interest to me. The big picture plan is to allow a user
to ultimately plot/print a USNG encoded map per their specification.
There are certainly a lot of other uses for the same sort of labeling
(that I can also use). I'm trying to organize the adds to MapServer so
they are reuseable, or at least set up things so the different types of
labeling are possible with as little additional coding effort as possible.
Your method of doing the margins from within the MapFile is an
interesting approach.
Some general questions to you (and anyone else interested in commenting):
* Do you see a need at all to display the grid labels along only two
edges, or even in just two axis but just once, along the center of the
page for example, both vertically and horizontally.
* Do you see a need to have a variable available for setting the outside
buffer zone area, in other words, for setting how far in (or possibly
out) from the edge of the map, the labels are printed?
* Do you see a need to have the GRID displayed as a TICed grid instead
of continuous lines, I'm not sure how to actually do this at the moment.
Might be a symbol placement sort of thing, with rotation instead of line
drawing. This is further down the list for me at this point though.
* Lastly, do you see a need for an entirely different approach to some
of these labeling/printing aspects, I've been toying with the idea (for
a couple of years now) of building a completely separate service that
can still be complimentary to MapServer and be programmed against in the
same manner from the client side, for templating a print function. The
basic idea would be to build a system where there is a layout canvas on
the client end, that can use URL resources as print objects, and allows
the user to layout where everything goes on a page, which most likely is
some sort of template for printing in pre-defined ways. Mapserver would
handle all the inclusive map grid line markup, but the real detailed
labeling could happen with this separate facility, specifically for
printing.
In the end, I think this labeling and grid stuff may push me over the
edge as far as trying out some stuff of our own. I would imagine that
we would start with some of the MapServ code to experiment with. I
think our end result might be too heavy to include in mapserv in
general. This GRID stuff though, has elements in both the direct
mapping as well as Print only aspects.
I've thought a lot about what should be considered a dynamic, online
navigation tool, vs what should be considered a "print" setup tool.
Many pieces cross the line, and that's where it gets murky on how to start.
bobb
Brent Fraser wrote:
> Bob,
>
> Good on you for pursuing this! While I think the current grid object
> satisfies most of mapserver implementors' needs, there is room for
> improvement. The ultimate would be a system that can produce reference
> system labels like those found on topos (some are very similar to your
> NG labels).
>
> First, I see there is still a typo in mapgraticule.c, line 347 (current
> SVN) should be
>
> dStartY = (pInfo->pboundinglines[0].point[1].y -
> pInfo->pboundinglines[0].point[0].y) * dDeltaX +
> pInfo->pboundinglines[0].point[0].y;
>
> (note the last array index value of 0 not 1)
>
> Second, (from my old notes on experimenting with labeling in v4.3) I
> changed 661 thru 682 to:
>
> switch( ePosition )
> {
> case posBottom:
> pShape->line->point[1].y = pLayer->map->height;
> pShape->line->point[0].y = pLayer->map->height - (
> fabs(rectLabel.maxx - rectLabel.minx) + 15 ); /* rectLabel is based
> on non-rotated text (x is along the width of text) */
> break;
>
> case posTop:
> pShape->line->point[1].y = 0;
> pShape->line->point[0].y = fabs(rectLabel.maxx - rectLabel.minx) + 15;
> break;
>
> case posLeft:
> pShape->line->point[1].x = 0;
> pShape->line->point[0].x = fabs(rectLabel.maxx - rectLabel.minx) + 15;
> break;
>
> case posRight:
> pShape->line->point[1].x = pLayer->map->width;
> pShape->line->point[0].x = pLayer->map->width - (
> fabs(rectLabel.maxx - rectLabel.minx) + 15 );
> break;
> }
>
>
>
> And regarding labeling "outside" the map, I arranged my map file to draw:
> 1. all the usual raster and vector layers
> 2. a grid layer
> 3. a "margin" layer of blanking polygons (see below)
> 4. a grid layer of type annotation so no lines are drawn
>
>
> Here's part of my map file (for version 4.3 so no telling what will happen
> with v5.x):
>
> SIZE 800 600
> :
> :
>
> LAYER
> NAME "Margin"
> TRANSFORM FALSE
> STATUS DEFAULT
> TYPE POLYGON
> CLASS
> COLOR 255 255 255
> END
> FEATURE
> POINTS 0 0 0 600 70 600 70 0 0 0 END
> POINTS 70 0 70 70 800 70 800 0 70 0 END
> POINTS 70 600 800 600 800 530 70 530 70 600 END
> POINTS 730 70 730 530 800 530 800 70 730 70 END
> END
> END
>
> #-----------------------------------------------------------
> LAYER
> NAME "NeatLine"
> TRANSFORM FALSE
> STATUS DEFAULT
> TYPE LINE
> CLASS
> COLOR 0 0 0
> END
> FEATURE
> POINTS 70 70 70 530 730 530 730 70 70 70 END
> END
> END
>
>
> #-----------------------------------------------------------
> LAYER
> NAME "GRID"
> PROJECTION
> "proj=latlong"
> # "ellps=sphere"
> "datum=WGS84"
> END
> # TYPE Line
> TYPE ANNOTATION
> # LABELCACHE off
> STATUS DEFAULT
> CLASS
> COLOR 128 128 128
> # LABEL
> # TYPE BITMAP
> # SIZE MEDIUM
> # COLOR 128 128 89
> # END
> LABEL
> color 0 0 0
> # COLOR 255 255 0
> # OUTLINECOLOR 0 0 0
> TYPE TRUETYPE
> FONT arial #bd
> SIZE 12
> POSITION UC # AUTO
> ANGLE AUTO
> # OFFSET 4 4
> # PARTIALS false
> # WRAP " "
> END # Label
> END
>
> GRID
> LABELFORMAT "DDMM"
> # LABELFORMAT "DDMMSS"
> # MINSUBDIVIDE 6
> # MAXSUBDIVIDE 6
> # MININTERVAL 1.0
> # MAXINTERVAL 1.0
> # MINARCS 6
> # MAXARCS 6
> END
> END
>
> #-----------------------------------------------------------
>
> END # MAPFILE
>
>
> But in the end it is somewhat hacky and not perfect. I think some
> additional objects and properties are needed. Last year I had a small
> rant regarding graticules on the OSGeo mailing list (with no specific
> solution reached). Here's one record of it:
>
> http://www.mail-archive.com/discuss@lists.osgeo.org/msg00935.html
>
> Keep up the good work!
> Brent Fraser
>
>
>> All,
>>
>> I've (we've) been messing with this GRID object and Labeling while trying
>> to get a USNG grid output with labels
>>
>> The results are meant to look like the left edge of the attached image.
>> The other three sides are being repositioned by some semi-known process.
>>
>> Essentially the labels should be:
>>
>> First two characters are super-scripted, the next two characters are
>> Normal, and the last four are also super-scripted. We've mussed with
>> MapServer code and come up with a method for handling the different
>> styling via a layer in the MAPFILE, using a LABELFORMAT option of NG1(1st
>> 2 chars), NG2 (2nd 2 chars) and NG3 (the last 4 chars). This is set up
>> along the lines of the DDMMSS options for LAT/LON.
>>
>> You can see that there is something wonky about the justification of the
>> labels. Right now we have space padding in front of and behind the
>> superscripted items, we'll address that separately once we get past this
>> label justification thing.
>>
>> So the question is, what is the sequence of events for a GRID with labels,
>> being applied to the result? Where in the Code could/should the
>> justifications be eliminated for the GRID writing process (I understand
>> that there needs to be a process for aligning along the edges) so that the
>> regular Labeling parameters, specifically, the OFFSET param, are adhered
>> to.
>>
>> I've tried all sorts of different combinations of settings to get the
>> right output, and I can only seem to get one edge to display properly.
>>
>> Furthering this output option a little more, anyone done any work with
>> labeling along the outside of a map image? I could use an option like
>> this for printing for example.
>>
>> Thanks
>>
>> bobb
>>
>>
>> The image results are from using this MapFile:
>>
>> MAP
>> NAME 'USNG'
>> SIZE 800 650
>> STATUS ON
>> ##IMAGECOLOR 254 254 254
>> ##EXTENT 540000 135000 600000 175000
>> EXTENT 593133.398829 170094.734526 593893.148973 170712.010326
>> UNITS FEET
>>
>> FONTSET ./0000_00/MN_Line_Experiments/fonts/font.list
>> SYMBOLSET ./0000_00/MN_Line_Experiments/symbols/symbol.list
>>
>> TRANSPARENT TRUE
>> IMAGETYPE PNG
>>
>> WEB
>> IMAGEPATH "/mnt/VECTOR00/output/"
>> IMAGEURL "/tmp/"
>> END
>>
>> # EPSG:26915
>>
>> LAYER
>> NAME "grid"
>> TYPE LINE
>> STATUS DEFAULT
>> CLASS
>> NAME "Graticule"
>> COLOR 0 0 0
>> SYMBOL 'circle'
>> SIZE 1
>> END
>> PROJECTION
>> "init=epsg:26915"
>> END
>> GRID
>> LABELFORMAT "NG1"
>> END
>> END
>>
>> LAYER
>> NAME "ng1"
>> TYPE LINE
>> STATUS DEFAULT
>> CLASS
>> LABEL
>> COLOR 0 0 0
>> FONT mono
>> TYPE truetype
>> SIZE 6
>> OUTLINECOLOR 255 255 254
>> FORCE true
>> POSITION cl
>> #OFFSET 0 0
>> END
>> END
>> PROJECTION
>> "init=epsg:26915"
>> END
>> GRID
>> LABELFORMAT "NG1"
>> END
>> END
>>
>> LAYER
>> NAME "ng2"
>> TYPE LINE
>> STATUS DEFAULT
>> CLASS
>> LABEL
>> COLOR 0 0 0
>> FONT mono
>> TYPE truetype
>> SIZE 12
>> OUTLINECOLOR 255 255 254
>> FORCE true
>> POSITION cl
>> END
>> END
>> PROJECTION
>> "init=epsg:26915"
>> END
>> GRID
>> LABELFORMAT "NG2"
>> END
>> END
>>
>> LAYER
>> NAME "ng3"
>> TYPE LINE
>> STATUS DEFAULT
>> CLASS
>> LABEL
>> COLOR 0 0 0
>> FONT mono
>> TYPE truetype
>> SIZE 6
>> OUTLINECOLOR 255 255 254
>> FORCE true
>> #OFFSET 0 0
>> POSITION cl
>> END
>> END
>> PROJECTION
>> "init=epsg:26915"
>> END
>> GRID
>> LABELFORMAT "NG3"
>> END
>> END
>>
>>
>> END ## end Map
>>
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>> mapserver-users at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>
>>
>>
>
>
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