[mapserver-users] Apply style to geojson based on property in geojson data

[Richard Greenwood]

Expressions are easy to mess up. To test if "value" is getting thru the
drive try using it as a label. That might help you to narrow down the
problem.

LABELITEM "value"
. . .
CLASS
    . . .
    LABEL
        . . .
    END
END

On Wed, Oct 25, 2017 at 2:08 AM, Tuffa <chris at wherryengineering.co.uk>
wrote:

> Hello Richard!
>
> > I haven't used geojson as a data source, but maybe if you shared a small
> > example of your map file and the data it would help.
>
> Here's some more information....
>
> mapfile.map (excerpt):
>
>   LAYER
>     NAME "countries"
>     STATUS OFF
>     TYPE POLYGON
>     CONNECTIONTYPE OGR
>     CONNECTION "africa.geojson"
>     DATA "select * from africa"
>     CLASS STYLE OUTLINECOLOR "#ff0000" END END
>     CLASS EXPRESSION ([value] >= 0 AND [value] <= 1000000) STYLE COLOR
> "#FFE397" END END
>   END
>
> I have tried numerous types of select statement in the DATA definition, but
> have failed to influence the styling based on the ‘value’ property added to
> the geojson file.  Of course, this may have all been in vain, if the GDAL
> driver does not support anything other than ‘select * from <layer>’, but I
> cannot tell from the documentation - MapServer, or GDAL - what is allowed.
>
> Here is an excerpt of the africa.geojson file, with the additional property
> ‘value’ added.  Following is the output from ogrinfo.
>
> {
>     "features": [
>         {
>             "geometry": {
>                 "coordinates": [
>                     [
>                         [
>                             [
>                                 8.621624,
>                                 36.941797
>                             ],
>                             [
>                                 8.621624,
>                                 36.941797
>                             ]
>                         ]
>                     ]
>                 ],
>                 "type": "MultiPolygon"
>             },
>             "properties": {
>                 "cartodb_id": 1,
>                 "created_at": "2013-11-12T16:15:59+0100",
>                 "name": "Algeria",
>                 "updated_at": "2013-11-12T16:15:59+0100",
>                 "value": 10000          <<<<<<<<<<<<<<<<<<<<<<<<<<<< custom
> property
>             },
>             "type": "Feature"
>         }
>     ],
>     "type": "FeatureCollection"
> }
>
>
> chris:tmp chris$ ogrinfo -summary -al africa.geojson
> INFO: Open of `africa.geojson'
>       using driver `GeoJSON' successful.
>
> Layer name: africa
> Geometry: Multi Polygon
> Feature Count: 1
> Extent: (8.621624, 36.941797) - (8.621624, 36.941797)
> Layer SRS WKT:
> GEOGCS["WGS 84",
>     DATUM["WGS_1984",
>         SPHEROID["WGS 84",6378137,298.257223563,
>             AUTHORITY["EPSG","7030"]],
>         AUTHORITY["EPSG","6326"]],
>     PRIMEM["Greenwich",0,
>         AUTHORITY["EPSG","8901"]],
>     UNIT["degree",0.0174532925199433,
>         AUTHORITY["EPSG","9122"]],
>     AUTHORITY["EPSG","4326"]]
> value: Integer (0.0)          <<<<<<<<<<<<<<<<<<<<<<<< here’s the
> additional
> property
> cartodb_id: Integer (0.0)
> created_at: DateTime (0.0)
> name: String (0.0)
> updated_at: DateTime (0.0)
>
>
> I haven't used geojson as a data source, but maybe if you shared a small
> example of your map file and the data it would help.
>
>
>
>
> --
> Sent from: http://osgeo-org.1560.x6.nabble.com/Mapserver-User-
> f4226646.html
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>



-- 
Richard W. Greenwood, PLS
www.greenwoodmap.com
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