Hi, long time i was playing around with navit and finally someone brought it to the Palm Pre. Now i found the navigation sometimes a little "obscure" which seemed to stem from the very strange "average speed" assumptions.
I live in a rural area and a lot of streets are "unclassified"'s which
navit thinks one can travel 10km/h average. A typical tertiary next to
it with a name - navit thinks its 40km/h.
More realistic speeds would be 60km/h on the unclassified and 80km/h
on a tertiary.
After looking into the converter maptool/osm.c i found very strange
assumptions and tags.
An unclassified in OSM terms is defined as beeing the lowest class of rural
interconnect roads whereas navit converts it to street_1_city which
is the same as a residential. In a residential area we typically have
a speed limit of 50km/h and an average speed of something like 10-20km/h
which would be okay in the xml vehicle description. But an unclassified
is something completely different - One is allowed to go 100km/h although
on most streets you wont do that but the average speed will be higher
than in the city
Also the usage of name to switch the city vs land for higher classified streets
looks quite odd. In Germany most higher classified streets have names in rural
areas too so currently navit assumes them all to be in the city and makes wrong
assumptions on travel speed. As mappers tend to map the citys first and tag
speed limits there as well the better assumption would be to make higher
classified
roads be land types and let the user reduce the average speed by setting the
maxspeed.
Thus i propose this patch:
Index: navit/navit/maptool/osm.c
===================================================================
--- navit/navit/maptool/osm.c (revision 3235)
+++ navit/navit/maptool/osm.c (working copy)
@@ -323,30 +323,22 @@
"w highway=motorway,rural=0 highway_city\n"
"w highway=motorway_link ramp\n"
"w highway=trunk street_4_land\n"
- "w highway=trunk,name=*,rural=1 street_4_land\n"
- "w highway=trunk,name=* street_4_city\n"
"w highway=trunk,rural=0 street_4_city\n"
"w highway=trunk_link ramp\n"
"w highway=primary street_4_land\n"
- "w highway=primary,name=*,rural=1 street_4_land\n"
- "w highway=primary,name=* street_4_city\n"
"w highway=primary,rural=0 street_4_city\n"
"w highway=primary_link ramp\n"
"w highway=secondary street_3_land\n"
- "w highway=secondary,name=*,rural=1 street_3_land\n"
- "w highway=secondary,name=* street_3_city\n"
"w highway=secondary,rural=0 street_3_city\n"
"w highway=secondary,area=1 poly_street_3\n"
"w highway=secondary_link ramp\n"
"w highway=tertiary street_2_land\n"
- "w highway=tertiary,name=*,rural=1 street_2_land\n"
- "w highway=tertiary,name=* street_2_city\n"
"w highway=tertiary,rural=0 street_2_city\n"
"w highway=tertiary,area=1 poly_street_2\n"
"w highway=tertiary_link ramp\n"
"w highway=residential street_1_city\n"
"w highway=residential,area=1 poly_street_1\n"
- "w highway=unclassified street_1_city\n"
+ "w highway=unclassified street_1\n"
"w highway=unclassified,area=1 poly_street_1\n"
"w highway=road street_1_city\n"
"w highway=service street_service\n"
Flo
--
Florian Lohoff [email protected]
"Es ist ein grobes Missverständnis und eine Fehlwahrnehmung, dem Staat
im Internet Zensur- und Überwachungsabsichten zu unterstellen."
- - Bundesminister Dr. Wolfgang Schäuble -- 10. Juli in Berlin
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