Re: [gdal-dev] software can display geotiff file in 3D viewer.

2010-04-04 Thread Volker Wichmann 

Markus Neteler schrieb:

2010/4/2 weixj2003ld :
  

Hi
Could you tell me some open source softwares(base on windows) that can
display geotiff files in 3D mode not in 2D mode?



GRASS GIS has the NVIZ 3D viewer included:
http://grass.osgeo.org/screenshots/viz.php

Download at:
http://grass.osgeo.org/download/

Markus
  

An alternative is SAGA GIS:
http://www.saga-gis.org
http://sourceforge.net/projects/saga-gis/

Have a look at
http://sourceforge.net/apps/trac/saga-gis/wiki/Climbing%20Mount%20St.%20Helens
on how to create a 3D View. To import a geotif to SAGA, have a look at 
the Import/Export - GDAL/OGR module library.


Volker

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[gdal-dev] max y is less than min y

2010-04-04 Thread weixj2003ld 
I read a .tif file ,and use the following code to get the MinX,MinY,MaxX and 
MaxY of the coordation of the tif image.
...
double *m_AdGeoTransform=new double[6];
poDataset->GetGeoTransform(AdGeoTransform);
nX=poDataset->GetReasXsize();
nY=poDataset->GetReasYsize();
 
MinX=AdGeoTransform[0];
MinY=AdGeoTransform[3];
 
MaxX =AdGeoTransform[0]+nX*AdGeoTransform[1]+nY*AdGeoTransform[2];
MaxY=AdGeoTransform[3]+nX*AdGeoTransform[4]+nY*AdGeoTransform[5];
...
 
I find that MaxY is less than MinY ,why?
Thk u in advance.
 
 
to get min x, max x,min y and max y .
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Re: [gdal-dev] max y is less than min y

2010-04-04 Thread Frank Warmerdam 

weixj2003ld wrote:
I read a .tif file ,and use the following code to get the MinX,MinY,MaxX 
and MaxY of the coordation of the tif image.

...
double *m_AdGeoTransform=new double[6];
poDataset->GetGeoTransform(AdGeoTransform);
nX=poDataset->GetReasXsize();
nY=poDataset->GetReasYsize();
 
MinX=AdGeoTransform[0];

MinY=AdGeoTransform[3];
 
MaxX =AdGeoTransform[0]+nX*AdGeoTransform[1]+nY*AdGeoTransform[2];

MaxY=AdGeoTransform[3]+nX*AdGeoTransform[4]+nY*AdGeoTransform[5];
...
 
I find that MaxY is less than MinY ,why?

Thk u in advance.


Wei,

GeoTransform[3] is the the Y origin, that is the Y value of the top left
corner of the top left pixel.In a normal georeferenced image this is
the north west corner, and since "northing" (Y) increases as you move
to the north the GeoTransform[3] value will generally be the maximum Y
for the image.

So I think you just need to compute:

  MaxY = AdGeoTransform[3];
  MinY = AdGeoTransform[3] + nX*AdGeoTransform[4]+nY*AdGeoTransform[5];

Best regards,
--
---+--
I set the clouds in motion - turn up   | Frank Warmerdam, warmer...@pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush| Geospatial Programmer for Rent

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