Tag Info

New answers tagged

0

You put the tags "arcgis-desktop" "gdal" so I assume QGIS might be an option too? Depending on the version of netcdf, you can simply load it and then use the usual Raster -> Extraction -> Contour workflow.


1

One way would be to do a Spatial Join. You'll use a one-to-one join_operation with the intersects match_option. In the field mappings you'll set it up so that if there are multiple matches found it will take the MAX value. Note that you may need to first create a numeric field in your flood polygons and convert any string based range values to integers (ie ...


0

The 'V' shape designates a valley where the river runs. If the valley is a gentle the contours will be more U shaped. Sharp sided valleys are shown with Vs. The Us or Vs point uphill - in the direction of the higher ground.


1

If you specifically want a single elevation (or specific elevations) as lines you can use Contour List (3d analyst, Spatial analyst). Unlike Contour (3d analyst, Spatial analyst) which creates contours at a specific interval the contour list tool produces contour isolines at specific elevation values.. for this example you would supply the value 0 for ...


0

Contour interval is a single number that defines the number of vertical units between contours. You can't have 10, 5, 2 unless you have different sets of contours. If it's 5, each line represents 5 vertical feet of change between lines. You can of course highlight 10m contours on an interval of 2 (every fifth) or 5 (every other). Contour lines are an ...


0

Poisson disc sampling via dart throwing ought to work for an arbitrary surface although so far I've only used it on planes and spheres myself. It's fairly slow though. You generate random points over the surface retaining those which are at least some minimal distance from the others that have been accepted. Stop when you've had some large number of ...


0

Often draftsperson add other items in the model space besides data; title blocks. profile graphs, external blocks, etc, etc. which are not necessarily near the actual source data. When you right-click on the layer in the TOC in ArcMap and chose "Zoom to Layer" and there is still nothing visible you can: Open the attribute layer of the "line" CAD layer ...


1

I'm not sure what the reason is for this duplications, but did you run v.clean with tool=rmdupl to remove duplicates? See also the v.clean documentation: http://grass.osgeo.org/grass70/manuals/v.clean.html


0

The problem was the missing -inodata flag of my gdal_contour command


0

This are the settings of my vector layer: g.region -p vector=CT_ISOBATAS_5m_ETRS89@froga projection: 1 (UTM) zone: 30 datum: etrs89 ellipsoid: grs80 north: 4818925.16988824 south: 4791485.92527958 west: 486512.5000001 east: 601274.08203047 nsres: 1.00011826 ewres: 1.00010965 rows: ...


1

What are your region settings? I tried this set of commands, and succeeded to create a DEM with negative values, with no problems: # Set region to low resoution GRASS 7.0.0 (ITM):~ > g.region -p res=5 # The contour vector GRASS 7.0.0 (ITM):~ > v.db.select test_ctours cat|elev 1|-100 2|-80 3|-60 4|-40 5|-20 # Create rasterized contours GRASS 7.0.0 ...


0

Using the Contour plugin. Generate isolines and/or filled contours a set of data points.


1

Line widths are determined at the rasterization step Other than lines in a vector image (e.g. SVG), lines in vector data do not have an inherent width. They are lines in a mathematical, not in a graphical sense. I assume that this is also the case for contours.shp, the output of the contour finding step with gdal_contour. Thus line width is determined by ...


0

If you export the lines as DXF, you should be able to load them into QGIS. Once they are in QGIS, you need to create an attribute that contains the elevation of each line (ie. a data column with a number). Depending on the total number of lines you could possibly do this manually. If doing it manually is not an option, you could concievably do some Python ...


0

i'm not sure what the default resolution is for gdal_translate if none is given, but you might try specifying some resolution based on the zoom level you desire per the docs - -tr xres yres : (GDAL >= 1.8.0) Set target resolution. The values must be expressed in georeferenced units. Both must be positive values



Top 50 recent answers are included