I think it wouold be better to have a conversion in the documentation.
Good idea.
I have calculated some examples, how many m^2 are one garmin_unit^2.
The conversion is dependent on the latitude value only (is this correct?):
1 garmin_unit^2 is:
Latitude m^2
-85° 0,79
Am 10.08.2013 13:21, schrieb WanMil:
I think results for lat=x° should equal lat=-x°?
This is what I would expect too. See attached ods-worksheet.
$ro = 6371.0 //[km]
$a = (90.0 - $lat1) * M_PI / 180.0;
$b = (90.0 - $lat2) * M_PI / 180.0;
$gamma = (abs($lon2 - $lon1)) * M_PI / 180.0;
$c =
Hi, me again ;)
Of course in the worksheet l is also in m, not in km. There are small
differences between +/- lat because of calculating always the rectangle
above the latitude. So the values below lat=0 are a little bit larger.
Rounding may also have a influence.
Henning
Hi,
I think results for lat=x° should equal lat=-x°?
Yes, simplified formula would be: area(latitude) = area_0*cos(latitude)
There is something wrong with your calculations for negative values.
Another problem.
My first idea was to use area function to change small polygons into
POI.
WanMil wmgc...@web.de writes:
area_size() gives the area size on resolution 24. Your effects must have
another reason.
Maybe the function should be garmin24_area() instead, then. I
understand that it's good to have area in garmin units because that's
the constraint this is intended to
Am 20.07.2013 13:23, schrieb Greg Troxel:
WanMil wmgc...@web.de writes:
area_size() gives the area size on resolution 24. Your effects must have
another reason.
Maybe the function should be garmin24_area() instead, then. I
understand that it's good to have area in garmin units because
area_size() gives the area size on resolution 24. Your effects must have
another reason.
WanMil
Actually, after using it, I think it is checked for each resolution! I
have some stuff disappearing at 23, that should still be there otherwise...
that's fine for me too.
On 13.07.2013 16:01,
Actually, after using it, I think it is checked for each resolution! I
have some stuff disappearing at 23, that should still be there otherwise...
that's fine for me too.
On 13.07.2013 16:01, WanMil wrote:
So actually this is a possibility to get rid of nonclosed shapes that
cause flooding or
The patch adds a new style function called garmin_area().
garmin_area() returns the size of an area in garmin-units ^2. It works
for polygons only. Unclosed ways return 0.
Please test it and let me know:
* Do you have a better name?
* What to do with multipolygons? Should garmin_area() return
A build including the patch can be obtained here:
http://files.mkgmap.org.uk/detail/146
WanMil
The patch adds a new style function called garmin_area().
garmin_area() returns the size of an area in garmin-units ^2. It works
for polygons only. Unclosed ways return 0.
Please test it and let
Hi WanMil,
great work!
Am 11.07.2013 23:04, schrieb WanMil:
The patch adds a new style function called garmin_area().
garmin_area() returns the size of an area in garmin-units ^2. It works
for polygons only. Unclosed ways return 0.
Please test it and let me know:
* Do you have a better
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