October 2013 - mkgmap-dev - The mkgmap lists

Commit: r2730: Characters not in a code page are now transliterated to ascii.
by svn commit 03 Oct '13

03 Oct '13

Version 2730 was committed by steve on Thu, 03 Oct 2013 Characters not in a code page are now transliterated to ascii. Move the transliteration step as an error handler for characters that do not exist in the target character set. This allows us to transliterate to ascii rather than displaying a question mark. This is a merge of branches/transliterate@2713

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question regarding length
by GerdP 03 Oct '13

03 Oct '13

Hi Steve, in mkgmap.jar (RouteArc) we use private static int convertMeters(double l) { // XXX: really a constant factor? // this factor derived by looking at a variety // of arcs in an IMG of Berlin; 1/4 of // what used to be here double factor = 3.28 / 16; return (int) (l * factor); } In the display tool we use // length should be in units of 16 feet item.addText("length %d (%dm)", len, (int)(len * 16 / 3.25)); I guess it should always be either 3.28 or 3.25? On the other hand, if the length is somehow related to the unit foot, why do I not see something like 0.3048? Gerd -- View this message in context: http://gis.19327.n5.nabble.com/question-regarding-length-tp5779909.html Sent from the Mkgmap Development mailing list archive at Nabble.com.

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higher precision instead of short-arc-removal?
by GerdP 03 Oct '13

03 Oct '13

Hi programmers, I am still working on the improved short-arc-removal routines. I found a few more special cases, and many of them are related to the fact that we are using the rounded lat/lon values (Garmin map units). Short excurse: A map unit is a 24bit integer value, means we can separate 2^24 = 16777216 different positions on the equator. By the way, the comment in Utils.toMapUnit "A map unit is an integer value that is 1/(2^24) degrees of latitude or longitue" is wrong, we store 1/(2^23) of a value that goes from -180.0 to 180.0. Means ~ 2.39m (40075 km / 16777216) near the equator. In Berlin, the value is ~ 1.45m for lon (lat is of course the same). So, the rounding error is 0.75 to 1.2m in this area. While these errors are not important when it comes to rendering a map, they might be important when it comes to routing. In some cases I find segments of ways with two points that are very close. Imagine a nearly vertical short segment. The rounding might move one point to the left, the other to the right, so that (in map units) with deltaLat = 1 and deltaLon = 1 the calculated bearing of ~ 148 is nonsense, as the real value is e.g 178. If I got this right, the Garmin routing algo uses the bearing value. We store it (heavily rounded to 8 or fewer bits), and the comments in RouteArc.encodeCurve() say that we are not sure about the img format. I think this might also explain why short arcs cause trouble, maybe it is not the short arc itself, maybe we simply write wrong data to the img when we store roads with points that are very close to each other? If that is true, we might better try to find out what we have to write to the img instead of messing around with short arcs? If only precision is the problem: Maybe we can Coord to store the lat/lon values with 30 bits precision? Gerd -- View this message in context: http://gis.19327.n5.nabble.com/higher-precision-instead-of-short-arc-remova… Sent from the Mkgmap Development mailing list archive at Nabble.com.

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mergeroads branch
by GerdP 03 Oct '13

03 Oct '13

Hi WanMil, I don't understand the changes in the OSM readers, e.g. // the type tag is required for relations - all other tags are filtered if (elem instanceof Relation == false || "type".equals(key) == false) key = keepTag(key, val); if (key != null) elem.addTag(key, val.intern()); I'd prefer to make sure that "type" is not filtered by keepTag(), because the keepTag method "inlines" the key. What was the reason for that change? Gerd -- View this message in context: http://gis.19327.n5.nabble.com/mergeroads-branch-tp5779967.html Sent from the Mkgmap Development mailing list archive at Nabble.com.

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highway count not fixed yet... - merge-roads-branch
by Felix Hartmann 03 Oct '13

03 Oct '13

Just cannot find the topic on the merge-roads-branch. Is it known that the highway count error is not fully fixed yet? I still get loads of them.

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Commit: r2724: Make sure that remove-short-arcs with no argument is evaluated with the default value (5.0)
by svn commit 03 Oct '13

03 Oct '13

Version 2724 was committed by gerd on Fri, 27 Sep 2013 Make sure that remove-short-arcs with no argument is evaluated with the default value (5.0)

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