Maps created with Oruxmaps desktop showing wrong coordinates

[Bert]

I scanned a DKW map of the coast of Holland as jpg. Via Oruxmaps desktop I got the following XML file.

When loaded into Oruxmaps, the Coordinates are completely wrong: places closer to Greenwich have a higher coordinate than places further east, places with same latitude have nevertheless different coordinates. What is wrong with this file ?

Please help. I'm a sailor, not a geologist.



<?xml version="1.0" encoding="UTF-8"?>

<OruxTracker xmlns:orux="http://oruxtracker.com/app/res/calibration">http://oruxtracker.com/app/res/calibration"

 versionCode="3.0">

<MapCalibration layers="true" layerLevel="0">

<MapName><![CDATA[pixels2]]></MapName>

<OruxTracker versionCode="2.1">

<MapCalibration layers="false" layerLevel="13">

<MapName><![CDATA[pixels2 13]]></MapName>

<MapChunks xMax="12" yMax="8" datum="WGS 1984:Global Definition@WGS 1984:Global Definition" projection="Mercator,3" img_height="512" img_width="512" file_name="pixels2 13" />

<MapDimensions height="3876" width="5916" />

<MapBounds minLat="51.576" maxLat="52.155" minLon="3.454" maxLon="4.296" />

<CalibrationPoints>

<CalibrationPoint corner="TL" lon="3.454" lat="52.155" />

<CalibrationPoint corner="BR" lon="4.296" lat="51.576" />

<CalibrationPoint corner="TR" lon="4.296" lat="52.155" />

<CalibrationPoint corner="BL" lon="3.454" lat="51.576" />

</CalibrationPoints>

</MapCalibration>

</OruxTracker>

</MapCalibration>

</OruxTracker>

[Bert]

I posted this on 18 March.41 have read it, none has replied. I am now preparing my boat to go to Denmark. It is disappointing not to get any help. I'll keep using the paper charts, although I believe that it is a minor problem, for which I have no soltution.  Bye Oruxmaps.

[rvb]

georeferencing scanned maps is not very easy. you must get nearly every pixel on the exact location, otherwise your digimap is useless.



the bigger your map, the bigger the deviations, the greater the effort to achieve 100% perfectness.

[Bert]

I don't understand. Every pixel ? When I define every corner of the map with coordinates and the size of the map in pixels, it is just a recalculation of X and Y to coordinates. On a Mercator projection that should be linear. I first tried to give the X and Y values as distance in kilometers, but that gave completely wrong figures, also in the script. When I replaced the distances in pixels (of the jpg), that problem disappeared, and the script was right. But when I use this map and script, the coordinates in Oruxmaps dont make sense. This could be because the map has not been coded correctly, or, whe placed in Oruxmaps, it cannot find it's references. Wha, by the way, is the meaning of "adding an empty map" ? Is this to get the map placed in a bigger "map" ?  A more detailed manual of Oruxmaps desktop would be welcome.

[rvb]

I use globalmapper for georeferencing, but I don't like the procedure. It requires a lot of time and skills and even then the result is moderate.



The homepage is refering to : GeoreferencingTool: Assembles a set of scanned map images to a seamless georeferenced raster map.



http://sourceforge.net/p/topomapcreator/wiki/GeoreferencingTool/">http://sourceforge.net/p/topomapcreator ... ncingTool/">http://sourceforge.net/p/topomapcreator/wiki/GeoreferencingTool/



Georeferencing is also possible in google earth.



http://www.geospatialtraining.com/Newsletter/ImageOverlay/Image%20Overlay%20Article.htm">http://www.geospatialtraining.com/Newsl ... rticle.htm">http://www.geospatialtraining.com/Newsletter/ImageOverlay/Image%20Overlay%20Article.htm