1

I need to acquire a very detailed topographic map of Istanbul, Turkey without any markers. Do you know such sources who provides these kind of maps? I tried to Google it, but the results were far from satisfactory. I found world topography from NASA, some low resolution images that does not worth much. There are a lot for US but unfortunately I failed to find one for Istanbul.


Actually since I don't the details of GIS, I don't know the technical terms to explain what I am looking for. But here is what I'll use the map for: I am going to print 3D version of Istanbul using some 3D printer, and display visualizations on top of it using projector hooked on the ceiling. In this case, I assume that I need either a 3D point cloud, or a 2D height map where I can deduce 3D points after some processing.

4

What you're after is a Digital Elevation Model (DEM) (wikipedia) which represents surface elevation as a single band raster (i.e. your 2D height map).

One starting point for getting DEM data is the USGS EarthExplorer data portal (http://earthexplorer.usgs.gov/) which allows you to select a region and search for data. If you use the map to zoom to Istanbul and the area you're interested in click the Use Map button to select your entire map view for data. In the Data Sets tab expand out Digital Elevation and select ASTER GLOBAL DEM which is 30m resolution DEM data. You may have to stick some scenes together as I believe the tiles neatly bisect Istanbul, but it will hopefully be enough to get you started.

  • Thanks a lot, it worked. One last question, please forgive my ignorance about the subject. Once I downloaded the tif files, even though I can see DEM on website with low resolution, I cannot see anything on default photo viewer software (Picasa Image Viewer). Should I do any additional step? – hevele Nov 18 '14 at 0:22
  • 2
    @MertToka No worries. Welcome to the field! I'd advise using QGIS to view the data - it's a single band tif file, and the values don't scale nicely for viewing in photo viewers (think of it as a 2d array of data). To get started take a look at the documentation on Loading Raster Data in QGIS – om_henners Nov 18 '14 at 0:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.