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location Potsdam, Germany
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visits member for 3 years, 2 months
seen 8 mins ago

18h
comment Sourcing GIS data from First World War (WW1)?
Oh, I just realized that I totally missed the letter "m" in "1:10m scale" up in the question... just ignore the second half of my first comment, please!
18h
comment Sourcing GIS data from First World War (WW1)?
I just spent an interesting afternoon in the current WW1 exhibition in the German National History Museum in Berlin a few weeks ago. They had lots of historical maps, but they were all at least 1:1000, mostly 1:10.000 and up.
22h
comment Sourcing GIS data from First World War (WW1)?
Not that I knew about any such repositories, but what kind of data are you looking for? Frontlines? Old cadastral maps? Battle plans? and 1:10 is a really, realy big scale. Even a floor plan for common shed is at least 1:200...
Jul
17
comment Auto populate field as concatenation of other fields
Exactly. I love to open a dbf file, temp save it as .ods file, and then work away with self-updating IF/THEN formulas, concat-operations etc. When your done, just make sure everything is correctly sorted, and save as dbf again. The formulas will be lost, of course, and only the values will remain - voila!
Jul
17
comment Auto populate field as concatenation of other fields
Actually, I meant "use the field calculator to update your FID column before switching to Calc". I am a big fan of Calc, to be honest - I did some demographic work a while ago, and changing age groups or counting certain populations is just so much easier in Calc, because there is less of an interface in the way (especially if you're quickly testing various alternatives). This might change with the new field calculator bar in 2.4, tough.
Jul
15
comment Auto populate field as concatenation of other fields
As long as you have a correct FID field (use the field calculator in QGIS before switching to Calc) you can resort your dbf in Calc as often as you like. Just remember to restore the correct order before saving - otherwise your attribute data will be mixed up.
Jul
11
answered Problem loading the contour plugin
Jul
11
comment View tiled shapefiles in QGIS 2.0 or greater as one layer?
You do seem to be right about MapServer - the documentation states that having a vector tile index might boost performance: mapserver.org/de/optimization/tileindex.html
Jul
10
comment View tiled shapefiles in QGIS 2.0 or greater as one layer?
I have to admit, i only have ever heard about tile indices for raster files. Why do you need such a index file for your shapefiles at all? I doubt there would be any performance advantage in QGIS even if such a plugin existed.
Jul
7
comment Invalid geometry
Clicking on the error message in QGIS' topology checker will bring you to the potentially problematic vertex or line. Do any problems show up when you check manually(most probably zero-length lines or overlapping geometry)? I can also imagine that ArcGIs and QGIS topology use different tolerance values (in this case, QGIS would have narrower ones...)
Jul
2
comment Where can i find Shapefiles of city along with the world file (.jgw) and the jpg image?
Well an algorithm able to identify building footprints from aerial pictures would be nifty, especially for us in e.g. OSM. And better wait 'till somebody else chimes in, too, just because I don't find any free test data doesn't mean there isn't any.
Jul
2
comment Where can i find Shapefiles of city along with the world file (.jgw) and the jpg image?
So you want to test your digitizing algorithm and then compare the results with the actual cadastral map? Will WMS services do the trick for you? Or maybe QGIS' OpenLayers plugin? I don't think you will find any freely available aerial picture tiles in your needed resolution (below 20 cm, I guess) online. As for free shapefile cadastral data - that's gonna be tough. All free example data I could find doesn't use the same area for their cadastral and aerial picture showcases...
Jul
2
comment Width and distance when using line patterns in QGIS
I think his problem is that the resulting crosshatch pattern is not recognizable in QGIS - I just tried his values, it's the same for me... (see above)
Jul
2
comment Width and distance when using line patterns in QGIS
EDIT: I just tried to print a 0,1mm/0,8mm crosshatch pattern from my CAD - it's barely readable. there is a reason the smallest line width is usually 0,18 mm ;).
Jul
2
comment Width and distance when using line patterns in QGIS
Well, the example you are linking is more like 1,2 mm distance and probably 0,25 mm line width. If you use those values the resulting pattern will look much closer to your example.
Jul
2
comment Where can i find Shapefiles of city along with the world file (.jgw) and the jpg image?
I don't think such a repository exists. Cadastral maps aren't usually publicly available, especially not as shape files. The same is true for aerial pictures. Which city are we talking about?
Jun
30
comment How to exactly georeference in QGIS
@simskopf: Then you might want to accept Jakob's hint as the correct answer. ;)
Jun
30
comment How to exactly georeference in QGIS
Well, you need to do that if the raster image and the reference data aren't in the same projection. Linear only tries to move the image to the correct location without transforming ("warping") it.
Jun
26
answered How to place labels under a vector layer?
Jun
25
comment How to place labels under a vector layer?
I could imagine that user8839 uses a cadastre map as a base map for what looks like electricity or freshwater lines. In this case you would like labels for some orientation, but they should never sit on top of the actual data. This is easily done in any CAD, but apparently not so in QGIS.