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Q: We are in the process of purchasing the ArcGIS extensions to use with Tuflow. Which extension is required or preferable to use – 3D Analyst or Spatial Analyst? Can either be used? A: Technically you don’t need either 3D Analyst or Spatial Analyst to run and use Tuflow. You can create inputs and look at outputs without them However, if you will need to be creating surfaces from points, modifying TINs or grids and manipulating rasters then you will need one or both. From what I can discover, Spatial Analyst is grid and interrogation focused and 3D Analyst is TIN and grid creation focused. There is a bit more discussion here. I think the best was forward would be to look at your wider organisation needs and pick from there, as Tuflow can be flexible and you can always use QGIS for the shortfall if you lack functionality in one package. For example, if you often receive data from developers in 3D contours or points and need to TIN these up, then maybe 3D analyst is the way. But if you are often interrogating large gridded datasets (like rainfall or landuse) then maybe Spatial Analyst is better. I would recommend seeing if you can get a free trial of either/both and seeing if these suit your needs. You can also work through the tutorials in ArcGIS and your selected add-ons to see how they affect your workflow. To the general Tuflow forum community, what do you use? How do they affect how you model? Fire away!
Hi all, I am trying to understand why the degree unit for MGA 56 (and other Transverse Mercator projections) is different between ESRI/Mapinfo and QGIS. After a bit of digging online I haven't had much luck. The below is a copy of the respective prj files. Note the Mapinfo Universal Translator (essentially FME) creates a prj file consistent with ESRI. ESRI/Mapinfo PROJCS["GDA_1994_MGA_Zone_56",GEOGCS["GCS_GDA_1994",DATUM["D_GDA_1994",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",500000.0],PARAMETER["False_Northing",10000000.0],PARAMETER["Central_Meridian",153.0],PARAMETER["Scale_Factor",0.9996],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]] QGIS PROJCS["GDA94_MGA_zone_56",GEOGCS["GCS_GDA_1994",DATUM["D_GDA_1994",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",153],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",10000000],UNIT["Meter",1]] I believe all software packages suggest I am using EPSG 28356. I am concerned that the small difference in units can lead to very slight shifts in large datasets and issues with snapping. If you have experienced these issues or have any thoughts it would be great to hear from you. Kind regards, Mitch. ESRI_MGA56.prj.txt QGIS_MGA56.prj.txt