The good news is that your suggestion... (and something I recognized when it
appeared among search results, but failed to recall: that the geography type
requires the st_prefix parameter (http://trac.mapnik.org/ticket/768))... has
allowed me to avoid that error and its friends. Maps are being rendered,
now. Thanks go out to you and Robert Coup for those corrections.
The bad news is that these points are not included in the rendered image. I
suspect the style configuration.
Also, I'm switching to a point symbolizer or PolygonPatternSymbolizer,
because I need a these circles filled with a radial gradient vector (SVG).
Also, if I have to use the point symbolizer, I need to parameterize or
apply filters to control the radius of the circles.
So, here's one of each symbolizer, as I *imagine* it should be configured
(I'm trying some fairly rash things, in these styles just at the moment,
which I don't expect to work, although I wish they would):
<Style name="location">
<Rule>
<Filter>[radius_estimate] > 0</Filter>
<MaxScaleDenominator>&maxscale_zoom0;</MaxScaleDenominator>
<PointSymbolizer ignore-placement="true" type="svg"
allow_overlap="yes" height="[radius_estimate]" width="[radius_estimate]"
file="/home/pwicks/projects/osm-rendering/stylesheets/symbols/radial_reversed_green_open.svg"
opacity="0.2" transform="scale(0.01996257, 0.01996257)" />
<TextSymbolizer name="[probe]" fontset_name="bold-fonts"
size="6" character_spacing="1" fill="rgba(0, 0, 0, 0.3)"
horizontal_alignment="middle" halo_fill="rgba(255, 255, 255, 0.3)"
halo_radius="2" wrap_width="10" avoid_edges="true"/>
</Rule>
</Style>
<Style name="location_radii">
<Rule>
<Filter>[geog] > 0</Filter>
<PolygonPatternSymbolizer
file="/home/pwicks/projects/osm-rendering/stylesheets/symbols/radial_reversed_green_open.svg"
type="svg" height="[radius_estimate]" width="[radius_estimate]" />
</Rule>
</Style>
<Layer name="location" srs="&srs4326;" status="on" >
<StyleName>location</StyleName>
<Datasource>
<Parameter name="dbname">earth</Parameter>
<Parameter name="estimate_extent">false</Parameter>
<Parameter name="extent_from_subquery">false</Parameter>
<Parameter name="st_prefix">true</Parameter>
<Parameter name="geometry_field">geog</Parameter>
<Parameter name="host">localhost</Parameter>
<Parameter name="password">[...]</Parameter>
<Parameter name="port">5432</Parameter>
<Parameter name="srid">4326</Parameter>
<Parameter name="table">(SELECT * FROM my_locations WHERE job_id
= &job_id;) as location</Parameter>
<Parameter name="type">postgis</Parameter>
<Parameter name="user">postgres</Parameter>
<Parameter name="extent">-180.0,-90.0,180.0,90.00</Parameter>
</Datasource>
</Layer>
<Layer name="location_radii" srs="&srs4326;" status="on" >
<StyleName>location_radii</StyleName>
<Datasource>
<Parameter name="dbname">earth</Parameter>
<Parameter name="estimate_extent">false</Parameter>
<Parameter name="extent_from_subquery">false</Parameter>
<Parameter name="st_prefix">true</Parameter>
<Parameter name="geometry_field">geog</Parameter>
<Parameter name="host">localhost</Parameter>
<Parameter name="password">[...]</Parameter>
<Parameter name="port">5432</Parameter>
<Parameter name="srid">4326</Parameter>
<Parameter name="table">(SELECT ST_Buffer(geog, radius_estimate)
as geog, radius_estimate FROM my_locations) AS geog</Parameter>
<Parameter name="type">postgis</Parameter>
<Parameter name="user">postgres</Parameter>
<Parameter name="extent">-180,-90,180,89.99</Parameter>
</Datasource>
</Layer>
Suggestions?
Rendering buffers of varying radii (or something similar) around data
points, using a transparent SVG with a radial gradient, is really very
important to me. I'm anxious to get this working as soon as I possibly can.
Andy Allan-2 wrote:
>
>
> Your geometry_field parameter (geog) doesn't match the output of your
> processing (radius). I'm not saying that'll fix it, but it'll not work
> as-is! You might also want to rename the "AS radius" bit to give a
> clearer hint that it's going to be a circle rather than the radius of
> a circle, just for posterity's sake.
>
>
--
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