[gdal-dev] How to read part of the tiff data and generate a new tiff file

[Chaitanya kumar CH]

weixj,

You can get some free samples at http://www.webgis.com/terr_us1deg.html

On Wed, May 2, 2012 at 1:45 PM, weixj <weixj2003ld at 163.com> wrote:

> Thank you for your answer.
> I want to know that where I can get the free DEM data?
> I want a sample data,and test my program.
>
> Thank you.
>
>
>
> At 2012-05-02 12:57:41,"Chaitanya kumar CH" <chaitanya.ch at gmail.com>
> wrote:
>
> weixj,
>
> Digital Elevation Model is a type of data. In this context, it is a grid
> of elevation values stored in a raster file.
> DEM refers to height. The underlying raster format can be anything.
>
> The only reference I found for .gmp format is "Global Mapper Package".
> Perhaps you can find more on the global mapper forums and by opening it in
> a binary editor.
>
> If the data is stored as raw data, you may be able to read it after
> creating a .vrt file to describe it.
>
> On Wed, May 2, 2012 at 8:03 AM, weixj <weixj2003ld at 163.com> wrote:
>
>>  DEM is a data format,and the file name extension has many formats,is it
>> right?
>> My colleage give me file  and its name is 90mDataHeight.gmp,and I use the
>> following code read it,and find that it can not open the file.
>>
>> code:
>> GDALAllRegister();
>>  poDataset=(GDALDataset
>> *)GDALOpen(fileName.toLatin1().data(),GA_ReadOnly);
>>  if(poDataset==NULL)
>>  {
>>   QMessageBox::warning(0,"","can not open file:"+fileName);
>>   return false;
>>  }
>>
>> I do not know why?
>> How many formats of DEM file?
>>
>> Thank you.
>>
>> 在 2012-04-25 20:11:45，"Chaitanya kumar CH" <chaitanya.ch at gmail.com> 写道：
>>
>> sure
>>
>>
>> 2012/4/25 weixj <weixj2003ld at 163.com>
>>
>>>  If the file is DEM?the same?
>>>
>>>
>>> At 2012-04-24 19:36:11,"Chaitanya kumar CH" <chaitanya.ch at gmail.com>
>>> wrote:
>>>
>>> weixj,
>>>
>>> You can use the -projwin option of gdal_translate utility.
>>>
>>> http://www.gdal.org/gdal_translate.html
>>>
>>> 2012/4/24 weixj <weixj2003ld at 163.com>
>>>
>>>>  I have a tiff file and four points' coordination(and they are in the
>>>> range of the min and max value of the coordination of the tiff file,I want
>>>> to generate a new tiff file,and the edge of it is constructed by the four
>>>> points.
>>>>
>>>> Thank you  in advance.
>>>>
>>>>
>>>> ------------------------------
>>>> 网易Lofter，专注兴趣，分享创作！ <http://www.lofter.com/>
>>>> _______________________________________________
>>>> gdal-dev mailing list
>>>> gdal-dev at lists.osgeo.org
>>>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>>>>
>>>
>>>
>>>
>>> --
>>> Best regards,
>>> Chaitanya kumar CH.
>>>
>>> +91-9494447584
>>> 17.2416N 80.1426E
>>>
>>>
>>>
>>> ------------------------------
>>> 网易Lofter，专注兴趣，分享创作！ <http://www.lofter.com/>
>>
>>
>>
>>
>> --
>> Best regards,
>> Chaitanya kumar CH.
>>
>> +91-9494447584
>> 17.2416N 80.1426E
>>
>>
>>
>> ------------------------------
>> 网易Lofter，专注兴趣，分享创作！ <http://www.lofter.com/>
>
>
>
>
> --
> Best regards,
> Chaitanya kumar CH.
>
> +91-9494447584
> 17.2416N 80.1426E
>
>
>
>


-- 
Best regards,
Chaitanya kumar CH.

+91-9494447584
17.2416N 80.1426E
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