Getting SQLite Working

[ajayre]

Hi, I am running Mapnik 0.6.0 on Windows XP. My data is in a SQLite
(Spatialite) database file and it is a simple linestring. When I try to
render it I get a blank map. There are no errors or warnings on the
output. Here is my script:

from mapnik import *
m = Map(800,600,"+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs")
m.background = Color('white')
sqlite_lyr = Layer('SQLite')
sqlite_lyr.srs = "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"
sqlite_lyr.datasource = SQLite(file='main.db', table='tours',
key_field='ROWID', geometry_field='the_geom',
extent='-110.801,32.2257,-110.799,32.2263')
sqlite_style = Style()
sqlite_rule_on = Rule()
sqlite_rule_on.symbols.append(PolygonSymbolizer(Color(250, 190, 183)))
sqlite_style.rules.append(sqlite_rule_on)
m.append_style('test style', sqlite_style)
sqlite_lyr.styles.append('test style');
m.layers.append(sqlite_lyr)
m.zoom_to_box(Envelope(-110.801,32.2257,-110.799,32.2263))
im = Image(m.width,m.height)
render(m, im)
im.save('demo.png', 'png') # true-colour RGBA
save_map(m,"map.xml")

If I then export my data as a shapefile from the database and render
that instead, then it works. I swap the datasource line for this one:

sqlite_lyr.datasource = Shapefile(file='./shapefile', encoding='latin1')

Everything else stays the same. Can anyone please give me some hints as
to what step I might be missing or where I should look for troubleshooting?

Thanks, Andy

--
Andy
PGP Key ID: 0xDC1B5864

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[Dane Springmeyer]

Hey Andy,

It looks like you need to specify:

<Parameter name="wkb_format">spatialite</Parameter>

As I've noted at http://trac.mapnik.org/ticket/362#comment:2

Dane



On Jun 16, 2009, at 8:52 AM, Andrew Ayre wrote:

> Hi, I am running Mapnik 0.6.0 on Windows XP. My data is in a SQLite
> (Spatialite) database file and it is a simple linestring. When I try  
> to
> render it I get a blank map. There are no errors or warnings on the
> output. Here is my script:
>
> from mapnik import *
> m = Map(800,600,"+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs")
> m.background = Color('white')
> sqlite_lyr = Layer('SQLite')
> sqlite_lyr.srs = "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"
> sqlite_lyr.datasource = SQLite(file='main.db', table='tours',
> key_field='ROWID', geometry_field='the_geom',
> extent='-110.801,32.2257,-110.799,32.2263')
> sqlite_style = Style()
> sqlite_rule_on = Rule()
> sqlite_rule_on.symbols.append(PolygonSymbolizer(Color(250, 190, 183)))
> sqlite_style.rules.append(sqlite_rule_on)
> m.append_style('test style', sqlite_style)
> sqlite_lyr.styles.append('test style');
> m.layers.append(sqlite_lyr)
> m.zoom_to_box(Envelope(-110.801,32.2257,-110.799,32.2263))
> im = Image(m.width,m.height)
> render(m, im)
> im.save('demo.png', 'png') # true-colour RGBA
> save_map(m,"map.xml")
>
> If I then export my data as a shapefile from the database and render
> that instead, then it works. I swap the datasource line for this one:
>
> sqlite_lyr.datasource = Shapefile(file='./shapefile',  
> encoding='latin1')
>
> Everything else stays the same. Can anyone please give me some hints  
> as
> to what step I might be missing or where I should look for  
> troubleshooting?
>
> Thanks, Andy
>
> --
> Andy
> PGP Key ID: 0xDC1B5864
>
> _______________________________________________
> Mapnik-users mailing list
> Mapnik-users@...
> https://lists.berlios.de/mailman/listinfo/mapnik-users

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[ajayre]

Yay! Works! So to confirm I now use:

sqlite_lyr.datasource = SQLite(file='./mapniktest.db', table='tours',
key_field='ROWID', geometry_field='the_geom', wkb_format='spatialite',
extent='-110.801,32.2257,-110.799,32.2263')

Thanks for the FAST help with this!

Andy

Dane Springmeyer wrote:
> Hey Andy,
>
> It looks like you need to specify:
>
> <Parameter name="wkb_format">spatialite</Parameter>
>
> As I've noted at http://trac.mapnik.org/ticket/362#comment:2
>
> Dane

--
Andy
PGP Key ID: 0xDC1B5864
_______________________________________________
Mapnik-users mailing list
Mapnik-users@...
https://lists.berlios.de/mailman/listinfo/mapnik-users