Broken / Missing line edges

Hi Guys,

I'm testing Mapnik 0.6.0 & 0.5.1 (on Windows platform) and came across a very strange scenario. I have noticed Mapnik sometimes cuts / slashes styled road edges (styled lines in my case) around the tile corners i.e. roads finish abruptly. I know there have been some problems with missing labels,symbols,etc but I cannot find anything on missing / cut styled edges. Is there a fix / workaround for this problem?

I have attached a png image highlighting the problem (with vector data shown on top of created rasters)  and the python script used to generate tiles. The original shp file used to create samples has been uploaded since 700kb exceeds max allowed limit here, download link given below.

http://pzh6gq.blu.livefilestore.com/y1pjcNP-HcqKN87z7hxUSwkHhozm_aC61po5hlFe9k8gChYhFVhj71M4Xwnq2wdpfoHIoNmJJw8tSVdBmYSKSVRhzOj__MJXaf5/sample.zip?download

I would greatly appreciate any help in this matter.

Thanks
--
Adnan Khan

'''
Created on 20 May 2009

Creates samples images from Mapnik.

Images are created in the same dir as base shp file for roads.
'''
from mapnik import *
import os

shp_file_loc = 'C:\\sample\\sample'
output_dir = os.path.dirname(shp_file_loc)
label_field = 'STREET_NAM'

tile_size = 800
m = Map(tile_size,tile_size,"+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +datum=OSGB36 +units=m +no_defs")
m.background = Color(240,240,240)

start_x,start_y,end_x,end_y = 475000,260000,477000,262000


def createSHPLayer(file_path,lyr_name,style_names):

    lyr = Layer(lyr_name)
    lyr.datasource = Shapefile(file=file_path,encoding='latin1')
   
    for style_name in style_names:
        lyr.styles.append(style_name)
   
    return lyr

def createLineStyle(style_name,width=7,rgb='orange'):
   
    s = Style()
    stk = Stroke()
    stk.width = width
    stk.color = Color(rgb)
    stk.line_cap = line_cap.ROUND_CAP
    r = Rule()
    r.symbols.append(LineSymbolizer(stk))
    s.rules.append(r)
    m.append_style(style_name,s)
   
    return s

       
def createLineText(style_name,field_name='stnm_base',font_size=10,rgb='black'):
   
    s2 = Style()
   
    r2 = Rule()
   
    t2 = TextSymbolizer(field_name,'DejaVu Sans Book',font_size,Color(rgb))
    t2.label_placement = label_placement.LINE_PLACEMENT
    t2.halo_radius = 1
    t2.halo_fill = Color('yellow')
    t2.allow_overlap = True
    t2.avoid_edges = True
    t2.max_char_angle_delta = 20
    t2.minimum_distance = 50
    t2.label_spacing = 100
    t2.avoid_edges = True
   
    r2.symbols.append(t2)
    s2.rules.append(r2)
   
    m.append_style(style_name,s2)
   
    return s2

# Create styles
createLineStyle('road fill',4.5)
createLineStyle('road border', 5.5, 'gray')
createLineText('road labels',label_field)

# Create source and append styles to it
road_layer = createSHPLayer(shp_file_loc, 'roads', ['road border','road fill','road labels'])
m.layers.append(road_layer)

for i in range(2):
    m.zoom_to_box(Envelope(start_x,start_y,end_x,end_y))
    render_to_file(m,'%s\\%s.png' % (output_dir,i),'png256')
    scale = m.scale()
    extent= m.envelope()
    upper_left_x_center = extent.minx+(scale/2)
    upper_left_y_center = extent.maxy+(scale/2)
    x_rotation = 0.0
    y_rotation = 0.0
    wld_string = '%f\n%s\n%s\n-%f\n%f\n%f\n' % (scale,y_rotation,x_rotation,scale,upper_left_x_center,upper_left_y_center)
    wld_file = open('%s\\%s.wld' % (output_dir,i), 'w')
    wld_file.write(wld_string)
   
    start_y = end_y
    end_y += tile_size







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