On Wed, Apr 28, 2010 at 10:03 AM, andrea antonello
<[email protected]> wrote:
> Hi Simone,
>
>> arcgrid reader should use the underlying values for the nodata, it
>> should be -9999 when it is an esri arcgrid, NaN when it is grass.
>>
>> Same should apply to aig, as I told you yesterday I would check the
>> underlying value first.
>
> sure. I was just signaling this to the list, because some could have
> my same problems and not noticing it.
>
> The problem is that:
> - arcgrid not always have -9999.0,

Indeed, we should the values as advertised in the header, if not let me know....

> as well as grass (grass by default
> uses the *, which isn't even a number and might give the parser
> troubles)

infact we should advertise Nan

Simone.


> - if you access that all programmatically, you need to know from the
> reader what the novalue it used is. Even if you know what the novalue
> really is.
>
> I'll have to look into this, but not sure I have the time right now. I
> will at least give a quick look and decide what to do with it.
>
> Cheers,
> Andrea
>
>
>>
>>
>> Simone.
>> -------------------------------------------------------
>> Ing. Simone Giannecchini
>> GeoSolutions S.A.S.
>> Founder - Software Engineer
>> Via Carignoni 51
>> 55041  Camaiore (LU)
>> Italy
>>
>> phone: +39 0584983027
>> fax:      +39 0584983027
>> mob:    +39 333 8128928
>>
>>
>> http://www.geo-solutions.it
>> http://geo-solutions.blogspot.com/
>> http://www.linkedin.com/in/simonegiannecchini
>> http://twitter.com/simogeo
>>
>> -------------------------------------------------------
>>
>>
>>
>> On Wed, Apr 28, 2010 at 9:54 AM, andrea antonello
>> <[email protected]> wrote:
>>> Ok, I will have to look into the code a bit better.
>>>
>>> AigReaders seem to give -Float.MAX_VALUE (probably depending on the
>>> content), while ArcgridReaders -9999.0.
>>>
>>> The gap seems to be in the step between imageio-ext and geotools.
>>>
>>> Will come back when I know something more.
>>>
>>> Cheers,
>>> Andrea
>>>
>>>
>>> On Tue, Apr 27, 2010 at 1:40 PM, andrea antonello
>>> <[email protected]> wrote:
>>>> Hi, I am trying to get the value that is used as novalue from a 
>>>> gricoverage.
>>>>
>>>> I was assuming something like:
>>>> GridSampleDimension[] sampleDimensions = inCoverage.getSampleDimensions();
>>>> double[] noDataValues = sampleDimensions[0].getNoDataValues();
>>>>
>>>> which returned me null.
>>>>
>>>> I then tried to get the categories to manually extract the novalue,
>>>> but these also ended up being null.
>>>> I am using the esri adf (AIGreader) that leverages imegio-ext.
>>>>
>>>> In order to spare time, can anyone tell me if the above is the right
>>>> way to get the value that is used as novalue?
>>>> In which case it is probably a bug and I would open a ticket in the
>>>> imageio-ext world.
>>>>
>>>> Thanks,
>>>> Andrea
>>>>
>>>
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>>
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