Practicing contour making of topography

Sliced landscape, area around Enschede. Vertical slices, z scale multiplied to show elevation differences more clearly. Used material: 3mm single flute cardboard. Test to find out how it looks. Cutting took about 20 minutes and the area and it’s features can be recognized very well.

Next will include hydraulic characteristics (Kh) of the subsoil, which has a lot of variety (clay, sand loam) in this area (glacial artefacts) and a model of the IJssel and adjacent waters around Zwolle will be made for students of a school in Zwolle.

Source files: AHN (Algemene hoogtekaart Nederland; digital information of the Dutch topography). Downloaded geotiff (32 bit) from AHN site converted with QGIS to 16 bit bitmap (black and white scale). Result converted this to a smaller bitmap (GIF, about 1000 x 2000 pixel), more convenient to make a 3D shape with bitmap to heightfield in Rhino with good enough resolution for test. The resulting mesh was sliced (contour) and curves were simplified to the same resolution as the thickness of the cardboard (3mm).

Still rather complicated, more automatisation is desired to speed up the process. Problems are: huge files to download and process, cumbersome combining of different area’s. A good solution would ( quick , easy to work with, small amounts of data) be to extract a screendump fro the AHN site, if it would be possible ( as on Belgian site) to define own color range and elevationdivision

Geotiff converted to smaller ( usable) bitmap for generating heightfield. Only top 2/3th of the picture was used to avoid the obviously erroneous jump in grey values. Black values (no data) were filled with surrounding area values (Photoshop cloning after selecting black areas = no data area) to avoid deep holes in the landscape. The dark slightly curved line in the middle is the train track between Enschede and Gronau. Near the top (North) the A1 is very well visible (highway near Oldenzaal, towards de Lutte in the northeast, top right) More to the South you see the track of the A35 to Gronau