Tutorial #22 - Dealing with different projections in QGIS

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  • Опубліковано 26 лис 2024

КОМЕНТАРІ • 4

  • @chrismichaelsaunders
    @chrismichaelsaunders 9 років тому

    What if you want to do an intersect between two vector files with different projections?

    • @wboykinm
      @wboykinm  9 років тому

      +christopher saunders You first have to choose which projection is better-suited to your map/analysis, the reproject the non-matching vector file to that projection like so: www.northrivergeographic.com/qgis-reprojecting-vector-data. This is a bit of a hassle, but it's important for reasons of geoprocessing accuracy to have all your data speaking the same geographic language.
      Once you've matched the two layers in the same projection, you can proceed with the intersect operation: infogeoblog.wordpress.com/2013/01/08/geo-processing-in-qgis/

  • @najibullahloodin2886
    @najibullahloodin2886 7 років тому

    hello,
    first of all thank you for the tutorial. I have a big homewo to simulate 2D of a river in Afghanistan using RAS MAPPER, HEC-RAS. I downloaded the geotiff file (DEM) of the river from USGS. before I start working with RAS MAPPER, I need to project the dem file and change the dem tif file to image. It can be done by QGIS. I have tried but it does not work.
    Could you please help me out with this regard.
    just send me your email, I will send you the dem file. I need the file to be projected to A coordinate system. Or if you already made any tutorial in this regard let me know.
    thank you very much.

    • @wboykinm
      @wboykinm  7 років тому

      Hi Najibullah - my apologies that this one is getting out of date, but your workflow should be possible in two steps with QGIS "Raster" menu:
      1. Raster --> Projections --> Warp (this will reproject)
      2. Raster --> Conversion --> Translate
      You'll still need to do some raster styling to make the output look the way you want it to. This section of a different tutorial might work for you: ua-cam.com/video/xB-cT_9TwJQ/v-deo.htmlm1s