Newcomb, Doug wrote:
Hi Folks,
I was running r.geomorphon,
http://grass.osgeo.org/grass70/manuals/addons/r.geomorphon.html, to generate
a landscape integer grid. I decided to share the output with a colleague
running ArcGIS. I exported with the raster attribute table option to HFA (
img , int16 ) format and passed it along. He noticed something in the
attribute table that was a bit odd.
The the output values for r.geomorphon are integer values from 1 -10 . The
output .img file
had the following in the following output for gdalinfo ( see below)
As you can see below, a 0 value was added to the color table and the
class_names start at 0 and not at 1 ( i.e, flat=0, but flat should equal 1)
. The pixel values do not change, the class names in the
GDALRasterAttributeTable are are associated with a lower pixel value
(shifted down one value.1--->0 and so on)
the fields in the attribute table as reported by GDAL are
Red, Green, Blue, Opacity, min, max, Class_Names
the first entry is
0, 0, 0, 0, 1, 1, flat
the pixel value 1 has the correct label "flat", but the color rule is wrong.
Looking at the Color Table (RGB with 11 entries) as reported by GDAL,
the first two entries are
0: 0,0,0,0
1: 220,220,220,255
this is correct, but different from the attribute table reported by
GDAL. The attribute table has thus correct labels but wrong colors.
The attribute table as created by GRASS contains in this case only
pixel values and labels, because it difficult to merge labels and
color rules. In GRASS, color rules and category labels are completely
separate, you can e.g. have 10 labels and 20 color rules. GDAL failed
to merge labels and color rules.
Markus M
Exporting via r.out.gdal to the same file format without a raster attribute
table or a color table gave a raster with values of 1-10.
running gdal 1.11.1 on ubuntu 12.04 with GRASS 7.0 snapshot 2014_10_25.
Not sure if it's a grass or gdal issue
gdalinfo output:
-----------------------------------------------------------------------------------
Driver: HFA/Erdas Imagine Images (.img)
Files: NED_SoApp_forms_cell25.img
NED_SoApp_forms_cell25.img.aux.xml
Size is 22854, 12004
Coordinate System is:
GEOGCS["GCS_WGS_1984",
DATUM["WGS_1984",
SPHEROID["WGS_84",6378137,298.257223563]],
PRIMEM["Greenwich",0],
UNIT["Degree",0.017453292519943295]]
Origin = (-86.094722219722215,37.848055555000002)
Pixel Size = (0.000277777777802,-0.000277777777801)
Corner Coordinates:
Upper Left ( -86.0947222, 37.8480556) ( 86d 5'41.00"W, 37d50'53.00"N)
Lower Left ( -86.0947222, 34.5136111) ( 86d 5'41.00"W, 34d30'49.00"N)
Upper Right ( -79.7463889, 37.8480556) ( 79d44'47.00"W, 37d50'53.00"N)
Lower Right ( -79.7463889, 34.5136111) ( 79d44'47.00"W, 34d30'49.00"N)
Center ( -82.9205556, 36.1808333) ( 82d55'14.00"W, 36d10'51.00"N)
Band 1 Block=64x64 Type=Int16, ColorInterp=Palette
Description = Layer_1
NoData Value=-32768
Metadata:
COLOR_TABLE_RULE_RGB_0=1.000000e+00 1.000000e+00 220 220 220 220 220 220
COLOR_TABLE_RULE_RGB_10=1.100000e+01 1.100000e+01 255 0 255 255 0 255
COLOR_TABLE_RULE_RGB_1=2.000000e+00 2.000000e+00 56 0 0 56 0 0
COLOR_TABLE_RULE_RGB_2=3.000000e+00 3.000000e+00 200 0 0 200 0 0
COLOR_TABLE_RULE_RGB_3=4.000000e+00 4.000000e+00 255 80 20 255 80 20
COLOR_TABLE_RULE_RGB_4=5.000000e+00 5.000000e+00 250 210 60 250 210 60
COLOR_TABLE_RULE_RGB_5=6.000000e+00 6.000000e+00 255 255 60 255 255 60
COLOR_TABLE_RULE_RGB_6=7.000000e+00 7.000000e+00 180 230 20 180 230 20
COLOR_TABLE_RULE_RGB_7=8.000000e+00 8.000000e+00 60 250 150 60 250 150
COLOR_TABLE_RULE_RGB_8=9.000000e+00 9.000000e+00 0 0 255 0 0 255
COLOR_TABLE_RULE_RGB_9=1.000000e+01 1.000000e+01 0 0 56 0 0 56
COLOR_TABLE_RULES_COUNT=11
Generated_with=GRASS GIS 7.0.0svn
LAYER_TYPE=athematic
Image Structure Metadata:
COMPRESSION=RLE
Color Table (RGB with 11 entries)
0: 0,0,0,0
1: 220,220,220,255
2: 56,0,0,255
3: 200,0,0,255
4: 255,80,20,255
5: 250,210,60,255
6: 255,255,60,255
7: 180,230,20,255
8: 60,250,150,255
9: 0,0,255,255
10: 0,0,56,255
<GDALRasterAttributeTable Row0Min="0" BinSize="1">
<FieldDefn index="0">
<Name>Red</Name>
<Type>0</Type>
<Usage>6</Usage>
</FieldDefn>
<FieldDefn index="1">
<Name>Green</Name>
<Type>0</Type>
<Usage>7</Usage>
</FieldDefn>
<FieldDefn index="2">
<Name>Blue</Name>
<Type>0</Type>
<Usage>8</Usage>
</FieldDefn>
<FieldDefn index="3">
<Name>Opacity</Name>
<Type>0</Type>
<Usage>9</Usage>
</FieldDefn>
<FieldDefn index="4">
<Name>min</Name>
<Type>0</Type>
<Usage>0</Usage>
</FieldDefn>
<FieldDefn index="5">
<Name>max</Name>
<Type>0</Type>
<Usage>0</Usage>
</FieldDefn>
<FieldDefn index="6">
<Name>Class_Names</Name>
<Type>2</Type>
<Usage>2</Usage>
</FieldDefn>
<Row index="0">
<F>0</F>
<F>0</F>
<F>0</F>
<F>0</F>
<F>1</F>
<F>1</F>
<F>flat</F>
</Row>
<Row index="1">
<F>220</F>
<F>220</F>
<F>220</F>
<F>255</F>
<F>2</F>
<F>2</F>
<F>summit</F>
</Row>
<Row index="2">
<F>56</F>
<F>0</F>
<F>0</F>
<F>255</F>
<F>3</F>
<F>3</F>
<F>ridge</F>
</Row>
<Row index="3">
<F>200</F>
<F>0</F>
<F>0</F>
<F>255</F>
<F>4</F>
<F>4</F>
<F>shoulder</F>
</Row>
<Row index="4">
<F>255</F>
<F>80</F>
<F>20</F>
<F>255</F>
<F>5</F>
<F>5</F>
<F>spur</F>
</Row>
<Row index="5">
<F>250</F>
<F>210</F>
<F>60</F>
<F>255</F>
<F>6</F>
<F>6</F>
<F>slope</F>
</Row>
<Row index="6">
<F>255</F>
<F>255</F>
<F>60</F>
<F>255</F>
<F>7</F>
<F>7</F>
<F>hollow</F>
</Row>
<Row index="7">
<F>180</F>
<F>230</F>
<F>20</F>
<F>255</F>
<F>8</F>
<F>8</F>
<F>footslope</F>
</Row>
<Row index="8">
<F>60</F>
<F>250</F>
<F>150</F>
<F>255</F>
<F>9</F>
<F>9</F>
<F>valley</F>
</Row>
<Row index="9">
<F>0</F>
<F>0</F>
<F>255</F>
<F>255</F>
<F>10</F>
<F>10</F>
<F>depression</F>
</Row>
<Row index="10">
<F>0</F>
<F>0</F>
<F>56</F>
<F>255</F>
<F>11</F>
<F>11</F>
<F>ERROR</F>
</Row>
</GDALRasterAttributeTable>
--
Doug Newcomb
USFWS
Raleigh, NC
919-856-4520 ext. 14 doug_newcomb@fws.gov
---------------------------------------------------------------------------------------------------------
The opinions I express are my own and are not representative of the official
policy of the U.S.Fish and Wildlife Service or Dept. of the Interior. Life
is too short for undocumented, proprietary data formats.
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