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I am running: gdal_contour -a elev hazard_interp4.asc haz_ak_contour_4_10 -i 10

the hazard_interp4.asc file has values in band 1 (singel band gray).

With the above command, I get a shapefile that has no values.

If I burn a color schema into the raster with gdaldem color-relief, then I can successfully create a contour shapefile. However I would prefer to not have to do this step.

Update: the output of hazard_interp4.asc is:

Driver: AAIGrid/Arc/Info ASCII Grid
Files: hazard_interp4.asc
Size is 300, 300
Coordinate System is `'
Origin = (-19003400.000000000000000,11484799.899999998509884)
Pixel Size = (10698.000000000000000,-15086.032999999999447)
Corner Coordinates:
Upper Left  (-19003400.000,11484799.900) 
Lower Left  (-19003400.000, 6958990.000) 
Upper Right (-15794000.000,11484799.900) 
Lower Right (-15794000.000, 6958990.000) 
Center      (-17398700.000, 9221894.950) 
Band 1 Block=300x1 Type=Float32, ColorInterp=Undefined
  Min=0.005 Max=0.595 
  Minimum=0.005, Maximum=0.595, Mean=0.141, StdDev=0.141
  NoData Value=-9999
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can you give us the output of gdalinfo hazard_interp4.asc -stats ? – mdsumner Feb 18 '13 at 11:32

Um, Minimum=0.005, Maximum=0.595 and you appear to be using a contour interval of 10. This might be the problem.


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I can't believe I did not see that! thanks – Bwyss Feb 19 '13 at 8:26

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