Top 25 kadaster for netherlands in Sqllite db

Masterijn · April 21, 2014, 10:28:30

From what i understand it is possible to generate a sqllite db from the kadaster maps. Somewhere here there is also a howto. Has anyone succeeded in creating such a map? I think vectormaps are the way to go, but these kadaster tile maps can be of help in some situations.

jusc · April 21, 2014, 17:28:46

Is there any online map? If yes, please post a link for this map.

berkley · April 21, 2014, 19:12:38

Official kataster maps are most times WMS...

Masterijn · May 11, 2014, 20:14:50

Today I indeed came across a web map service for this data. Also a full download in GeoTiff data. What would be the best approach to get this data offline? I'm trying to make things work with Mobile atlas creator, but no success yet. Do I need, beside the url, a more detailed description/parameters of the wms?
I'm a bit stuck, I guess trial and error doesn't work without some pervious experience.

berkley · May 11, 2014, 21:52:28

A good start would be a link. So others can have a look.

Masterijn · May 12, 2014, 00:37:57

That would be great!
Recently the dutch maps are made public via a viewer:
http://pdokviewer.pdok.nl
In this viewer some wms can be shown, this one
http://geodata.nationaalgeoregister.nl/top25raster/ows?SERVICE=WMS&
Is the one with the most popular mapdata.
Maybe the coordinate system isn't supported by Mobac?

edit
I got it working, but because this data is already tiled at the server, and the tiles need to be resized the quality is somewhat disapointing. There is also a top10 wms, which is of a higheer quality, but has lesse geo objects.
Wouldn't it be nice if Locus supported a directory full of GeoTiff files? Then this would solve the resizing problem. Tiff files are b.t.w. not so hard to parse.

Menion · May 24, 2014, 08:11:54

I'm worried they are. At least on Android you need some 3rd party c++ library, because Android do not have own tiff reader I as a developer may reause and on Android is also not available globally used Java JAI library that is able to read Tiff images on desktop computers.

Masterijn · May 24, 2014, 11:56:32

Lots of years ago, i did some tiff file parsing my self at a binary stream/block level. I found it quite straight forward. There's of course a difference between decyphering the container (what a tiff file is at the highest level) and understanding and using all its possible data. My guess is dat a GeoTiff has some tagged fields in which coordinates can be extracted, and a larger blob where a whole png or jpg file resides. If thats the case, a high level parser is not needed. Or maybe the contained jpg and png data are without their own "header" and only raw image data. In that case an image decyphers is needed, which works without headers. That might be hard to find.

edit
here are my new thoughts. I examined the geotiffs i've got. They are uncomprompressed indexed images. No png or jpg. Just raw scanline data. I took a look at my own tiff parsing of ten years ago. It was some hundred lines of code, and could only read uncompressed, 4 samples per pixel images. To make it work for a few more formats it would propably tripple the coding effort. Locus could also limit the types of image data supported. There are a lot of tool which can convert to a specific tiff format. There are also tools who can put the geo stuff back in from sidecard files, if it's lost in conversion. Going forward more image types could be supported, to make it more user friendly.

Menion · May 24, 2014, 17:45:27

I agree that support more formats should be more then useful, anyway I wasn't able to find any simple documentation for such formats like Tiff, GeoTiff, GeoPDF and so on. If you have any information you used for your own reader, please share it with me and I'll gladly check what is possible to do with it.

Masterijn · May 24, 2014, 20:01:43

GeoTiff is just a tiff-file with some extra info so for 90% normal tiff documentation can be used. The geo stuff are an extension, but follow the tiff way of doing stuff. I can send you my Delphi implementation, but I think the record stuff is handled different in Java. But as an example it couldn't be more easy. the class converts Tiff data to Png data via a png encoder. It shows getting the image size, reading the pixel data and a bit more. I think it was an evenings work.