Hi Mike,
thanks again. I stumbled over a change in this section:
old:
The --overview-mapname option can be used to change these names. If
the mapset is sent to the device from MapSource, it will enable
find by name and address search on the GPS.
new:
The --overview
Message: 4
Date: Tue, 23 Jan 2018 15:15:07 +
From: Gerd Petermann
To: Development list for mkgmap
Subject: Re: [mkgmap-dev] Open source GIS systems and DEM
Hi Mike,
I have never used any GIS system. I just download zipped hgt files from e.g.
http://viewfinderpanoramas.org/Coverage%20map%
Hi Gerd,
thanks for noticing :)
I hope anyone testing these maps will correct options for bicubic-spline.
Now there is a difference. Bicubic-spline looks more smooth than
bilinear, but the heights of peaks is lower, which is unexpected.
So again, bicubic looks the best.
--
Best regards,
Andr
Hi Andrzej,
I think you don't see a difference between bicubic and bicubic-spline because
your script uses
the same option bicubic for both ;-)
Gerd
Von: mkgmap-dev im Auftrag von Andrzej
Popowski
Gesendet: Dienstag, 23. Januar 2018 22:17:21
An: mkgma
Hi Gerd,
thanks for option. I have prepared a set for tests:
http://files.mkgmap.org.uk/download/407/interpolation.7z
This set creates maps with different resolutions and interpolations. I
have created a direct route and compared height profiles created with
different maps. Here my observatio
Hmm, when I first set up my config file (quite a long time ago), I could
only get it to work after examining the one produced by splitter, which has
colons in it. However, after trying again, it does indeed work with equals
as well, so not sure what was going wrong before. Please find attached an
u
Hi all,
see http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4081
Please ignore run time of bicubic-spline method for now, I think optimized
version should be as slow as bicubic, at the moment it is slower.
Gerd
Von: mkgmap-dev im Auftra
Hi Gerd and Andrzej
I think that makes sense top make it more flexible.
I found the following interpolation
NearestNeighbor
Bilinear
BicubicCardinal
BicubicBSpline
BicubicBCSpline
Nick
On 23/01/2018 15:28, Andrzej Popowski wrote:
Hi Gerd,
maybe we can wait a bit with optimization? W
Hi Andrzej,
okay, I'll try to add such an option.
Gerd
Von: mkgmap-dev im Auftrag von Andrzej
Popowski
Gesendet: Dienstag, 23. Januar 2018 16:28:26
An: mkgmap-dev@lists.mkgmap.org.uk
Betreff: Re: [mkgmap-dev] DEM: performance with bicubic interpolation
Hi Gerd,
maybe we can wait a bit with optimization? What I would like to get is
an option for mkgamp, that will allow for testing quality of all these
versions of interpolation. For now we have bilinear, bicubic and bicubic
spline. This all could be included in code and selected by user.
--
Hi,
I agree with Henning. BTW: It seems that the format --option:value is also
supported on the command line.
Gerd
Von: mkgmap-dev im Auftrag von Henning
Scholland
Gesendet: Dienstag, 23. Januar 2018 16:12:24
An: mkgmap-dev@lists.mkgmap.org.uk
Betreff
Hi Gerd and Henning,
> If accuracy of srtm is +- 10m and the difference between
> with/without interpolation is +-1m, then it's definitely not worth
> spending any effort on interpolation.
This is not like interpolations error is placed within source data
error. This error is added to data erro
Hi Mike,
I have never used any GIS system. I just download zipped hgt files from e.g.
http://viewfinderpanoramas.org/Coverage%20map%20viewfinderpanoramas_org3.htm
unzip them into one dir called srtm3 and feed that to mkgmap.
Gerd
Von: mkgmap-dev im Auftr
Hi Mike,
are you sure, = needs to be replaced by : in read-config-file? I'm using
= and it seems to work. (At least I think/hope so)
Henning
On 23.01.2018 22:35, Mike Baggaley wrote:
> Hi Gerd, please find attached a patch to correct and improve the
> documentation of the --read-config command li
Hello. For those of you that use an open source GIS system, I would
like to ask you why you chose the one you use. When developing the
DEM functionality for mkgmap, is a certain system preferred? I have
GRASS installed, but I keep hearing about QGIS.
Mark Bradley
___
Hi Gerd, please find attached a patch to correct and improve the
documentation of the --read-config command line argument.
If it looks OK to you, please commit it.
Thanks,
Mike
configdoc.patch
Description: Binary data
___
mkgmap-dev mailing list
mkgma
Maybe I'm thinking too scientific about it, but what benefit should be
expected when using lower --dem-dist values then the source can provide?
The interpolation is finally done by the Garmin software while
displaying the elevation data. At least I'm getting more elevation data
points in Basecamp t
Hi Henning,
yes, we have to scale hgt resolution to garmin resolution, this is not about
voids.
We may use the same algo to fill voids. I think this link is quite interesting:
https://web.archive.org/web/20051024202307/http://www.geovista.psu.edu/sites/geocomp99/Gc99/082/gc_082.htm
Gerd
_
Hi Andrzej,
I think this code is optimized for the case that you use fillArray() once and
calculate the interpolation with
multiple different combinations of qx + qy.
When you use e.g. a 3'' hgt file with dem-dists=9936,... this happens rarely.
When you use the same file with dem-dists=2000
this
For srtm I found elevation accuracy of 6m in wikipedia, so my 10m was
not that unrealistic.
Btw. We are talking about interpolating from hgt-data position to
Garmin-data position, aren't we?
For filling voids, it would be a good idea to use some spline
interpolation as written here:
https://en.wi
Hi Andrzej,
I also suggest to make interpolation optional.
So far I don't understand your argument. I agree, compilation time is
not the only criteria. The question is, what is the benefit for the user.
For example: If accuracy of srtm is +- 10m and the difference between
with/without interpolati
Hi Gerd,
there are different kind of bicubic interpolations. I'm not good at this
math, I think the previous version was actually bicubic spline
interpolation. See other possibilities here:
http://mrl.nyu.edu/~perlin/cubic/Cubic_java.html
I don't know, which type of spline or cubic interpolat
Hi all,
the bicubic interpolation that was introduced with r4072 is quite slow compared
to bilinear interpolation.
I have already changed the code to use a faster method in r4076 but
you should still expect that run time for DEM calculation increases by up to
~100% compared to code r4071,
actu
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