Re: [Opengrads-devel] Shapefile extension: first crack

[Efren S. <efr...@me...>]

Arlindo,

With the perl interface, can you encode colors in a shapefile?

We shouldn't encode colors in the shapefiles; I was hoping to use these
shapefiles in conjunction with Mapserver and let the coloring to =
mapserver
.map configuration file.  However, we should encode some values about =
the
shape in the .dbx file so that we can use mapserver's .map file CLASS =
value,
which defines thematic classes for a given layer.  A CLASS has an =
EXPRESSION
value
that we can use to select coloring, etc., based on a value encoded in =
the
.dbx file.  For instance, here is simple sample for coloring Tropical
Cyclone Warnings Wind Radiis/Track:

  LAYER
    NAME "al062007_019_34ktWndRadii"
    GROUP "tcw"
    METADATA
      "wms_title" "al062007_019_34ktWndRadii"   ##required
    END
    TYPE  POLYGON
    STATUS  OFF
    DATA  /otsr/shapefiles/2007091100/al062007_019_34ktWndRadii

      LABELITEM "RADIUS_NM"

      CLASS
        NAME "al062007_019_34ktWndRadii"
        OUTLINECOLOR 255 0 0
        LABEL
        MINFEATURESIZE 50
        MINDISTANCE 150
        POSITION CC
        SIZE TINY
        COLOR 0 0 0
      END
      DEBUG ON
    END

    DUMP TRUE
    PROJECTION
      "init=3Depsg:4326"   ##recommended
    END
  END # Layer al062007_019_34ktWndRadii

  LAYER
    NAME "ep102007_017_track"
    GROUP "tcw"
    METADATA
      "wms_title" "ep102007_017_track"   ##required
    END
    TYPE  LINE
    STATUS  OFF
    DATA  /otsr/shapefiles/2007091100/ep102007_017_track

      LABELITEM "STM_NAME"

      CLASS
        NAME "ep102007_017_track"
        COLOR 0 0 0
        LABEL
          MINFEATURESIZE 50
          MINDISTANCE 150
          POSITION CC
          SIZE TINY
          COLOR 0 0 0
        END
        DEBUG ON
      END

    DUMP TRUE
    PROJECTION
      "init=3Depsg:4326"   ##recommended
    END
  END # Layer ep102007_017_track

- how to draw a line in black, and another in green

Mapserver takes care of the drawing for us via the .map file by using
OUTLINECOLOR

- how to have a rectangle filled "blue"

Mapserver takes care of the drawing for us via the .map file by using =
COLOR

- how to define new colors from (red,green,blue) values

COLOR and OUTLINECOLOR take RGB values as shown above.

Do you have access to any GIS software? Is there a free alternative to
ARC/View? Which one do you recommend? I just want a way to see if the =
file
we eventually produce with GrADS can be visualized by standard GIS =
software.

Lets use Mapserver from UMN: http://mapserver.gis.umn.edu.  Thanks.

Efren