Re: [UMN_MAPSERVER-USERS] How to create tiles accurately with MapServer?

[Teemu Mäkelä]

Hi,

Here is some more information:
- I use WMS connection to generate the tiles.
- There is no data projecting.
- Extents are determined in WMS request. Extents for each tile are calculated so that tiles do not overlap.

Manfred Meier sent the reply, which included some images representing the same problem.

Here is a sample of the image (pixels does not match because this example if just screen shot manually merged).


Here is a sample from the map file:
MAP
        NAME        AOI_map
         STATUS ON

        IMAGETYPE        png
        EXTENT        3425034.79743042 7433326.6782573 3426828.755 7436220.1702233
                 
         SHAPEPATH "D:/webpages/indexfiles/"
         
         UNITS        meters
         PROJECTION
                  "init=epsg:2393" # 2393 = YKJ  
         END

OUTPUTFORMAT
  NAME JPEG
  DRIVER "GDAL/JPEG"
  IMAGEMODE RGB
  EXTENSION "JPEG"
END

OUTPUTFORMAT
  NAME bmp
  DRIVER "GDAL/BMP"
  MIMETYPE "image/bmp"
  IMAGEMODE RGB
  EXTENSION "bmp"
  FORMATOPTION "WORLDFILE=ON"
END


# Aerial images
LAYER
        NAME        "aerial"
        GROUP        "aerial"
        TYPE        RASTER
        STATUS        DEFAULT
       
        MINSCALE 40
        MAXSCALE 50000

        PROCESSING "RESAMPLE=AVERAGE"

        PROJECTION
                "init=epsg:2393"
            END
       
        TILEINDEX "ilmakuvat.shp"
END

LAYER
        NAME        MHGIS_GISE1_KIINTE
        DATA        data/MHGIS_GISE1_KIINTE.shp
        TYPE        LINE
        STATUS        DEFAULT
        TRANSPARENCY        0
       
       

        GROUP        UserData

    PROJECTION
      "init=epsg:2393"
    END

       
        CLASS
                STYLE
                        OUTLINECOLOR        254 255 254
                        COLOR        254 255 254
                END
        END

   
END

LAYER
        NAME        AOI
        DATA        data/AOI.shp
        TYPE        POLYGON
        STATUS        DEFAULT
       
       
       

        GROUP        UserData

    PROJECTION
      "init=epsg:2393"
    END

       
        CLASS
                STYLE
                        COLOR        0 0 255
                END
        END

   
END




END

Teemu

Stephen Woodbridge <[EMAIL PROTECTED]> Sent by: UMN MapServer Users List <MAPSERVER-USERS@LISTS.UMN.EDU> 28.10.2006 16:55 Please respond to Stephen Woodbridge

To:        MAPSERVER-USERS@LISTS.UMN.EDU         cc:                 Subject:        Re: [UMN_MAPSERVER-USERS] How to create tiles accurately with MapServer?

Teemu Mäkelä wrote:
>
> Hi,
>
> I should create tiles. I have linear features and in mapfile I've
> defined the line to be drawn with width of 1 pixel.
>
> On the border of tiles:
> CASE A:
> - Line continues OK from tile A to tile B, if line crosses the tile
> border with angle of 45-90 degrees.
> CASE B:
> - Line does not continue (small gap), if line crosses the tile border
> with angle of 0-45 degrees. Gap is the problem! Size of the gap depends
> on the angle. If angle is 5 degress, gap is about 10 pixels; if angle is
> 30 degrees, gap is about 3 pixels.
>
> Any idea how to get rid of the gaps on lines?
>
> Teemu

Hi Teemu,

I think we will need more info to help. Can you post your mapfile
please. Also how are you generating the tiles? ka-map?, mapserv cgi,
mapscript? Are you projecting the data? How do you determine the extents
of tile A and B?

-Steve W

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