5

is there any analogue of the ArcGIS "topo to raster" tool in QGIS? I need to creates surfaces from shp for some cases from points and for some from lines and this instrument is very convenient.

matt wilkie
  • 28,176
  • 35
  • 147
  • 280
laechoppe
  • 549
  • 2
  • 6
  • 15
  • 3
    It sounds like you are looking for a QGIS wrapper to ANUDEM - I don't think there's anything available but you could start looking here – PolyGeo Mar 19 '13 at 11:08

1 Answers1

5

No there isn't a QGIS analogue to TopoToRaster (actually ANUDEM)*. There isn't an analogue anywhere else that I'm aware of either for that matter.** (If you know of others please chime in.)

In brief ANUDEM "Interpolates a hydrologically correct raster surface from point, line, and polygon data."

The key point that differentiates ANUDEM from other frequently seen DEM generation methods is "hydrologically correct". Meaning the resultant elevation surface has water drainages that are connected, and that (theoretically) a water droplet placed up-slope will not get caught in a depression somewhere along the way before reaching the bottom of the drainage basin. ('Theoretically', because it depends on the quality of source data and correct twiddling of the configuration knobs at DEM generation time; e.g. the tool needs to be used correctly).

ANUDEM achieves it's drainage enforcement by incorporating hydro data -- watercourses (lines) as a kind of soft-breakline and waterbodies (polygons) -- which don't have elevation info along with contours and spot heights which do.

If the water-smart aspect of ANUDEM is not relevant for your project and you just need a continuous elevation surface from elevation vectors then Creating DEM from contours in QGIS? [and GRASS] is a good place to start.

If you do need drainage enforcement then go straight to the source and get ANUDEM. It's expensive (~$700 Academic, ~$2500 Commercial) but still cheaper than buying ArcGIS Desktop and 3D Analyst.

* TopoToRaster is custom version of ANUDEM from Mike Hutchinson of the Australia National University licensed by Esri (see here for usage tips).

** There is also the AverStar corporation which produced "drainage enforced elevation models" (DE-DEM) for the USGS and US Forest Service in the 1990s, but their software is/was never available for use or sale outside the company.

matt wilkie
  • 28,176
  • 35
  • 147
  • 280
  • 1
    For an approximation of the ANUDEM model using SAGA GIS (using R and rsaga example code); see chapter 10, section 10.6.1 "Objective selection of the grid cell size (pp 231) in: A Practical Guide to Geostatistical Mapping. http://spatial-analyst.net/book/system/files/StreamMap.pdf – Jeffrey Evans Jan 22 '18 at 16:09