On 8/23/2010 3:05 PM, Even Rouault wrote:
Le lundi 23 août 2010 05:28:17, Stephen Woodbridge a écrit :
Even,
It seems the adding:
#include
resolves the segv issue.
Strange, I think there's no particular good reason why it worked with GTiff and
not VRT. I assume you compile on a 64bit platfo
Le lundi 23 août 2010 05:28:17, Stephen Woodbridge a écrit :
> Even,
>
> It seems the adding:
>
> #include
>
> resolves the segv issue.
Strange, I think there's no particular good reason why it worked with GTiff and
not VRT. I assume you compile on a 64bit platform and that without header the
Steve,
Excellent info! I had been contemplating using GDAL's VRT format to create
an elevation web service so I could display X,Y and Z on mouse moves in web
mapping, but was unsure about the performance. Looks like fcgi could work.
FYI, I think I'll use Google's XML format
(http://co
Even,
It seems the adding:
#include
resolves the segv issue.
I would recommend changing the example in:
http://www.gdal.org/gdal_tutorial.html
To include that in the section "Reading Raster Data" because the example
C code uses CPLMalloc(). It would also be very helpful to add:
...
CPLFr
Stephen,
at first sight, I don't see anything wrong with your code.
You need to include "cpl_conv.h" for CPLMalloc(). And memory allocated with
CPLMalloc() should be freed with CPLFree(). The doc is there :
http://gdal.org/cpl__conv_8h.html (http://gdal.org/ -> API reference
documentation ->
OK, well may to answer my own question by reading the GDAL API Tutorial
and taking a guess at some parts I came up with the following. This is
basically just a copy of the tutorial and at the end I added some code
that I'm hoping reads the correct pixel for my lat,lon and prints out
the elevati
Stephen,
Refer to http://www.gdal.org/gdal_tutorial.html for help in opening the vrt
dataset using gdal.
Use the transformation coefficients from GDALGetGeoTransform() to translate
between lat/long and line/pixel.
http://www.gdal.org/classGDALDataset.html
On Sun, Aug 22, 2010 at 3:37 AM, Stephen
So I have been able to download the NED data and I have US coverage.
The data is in GeoTiff and all in a single band Int16 format.
I have create a ned.vrt file.
So I'm interested in writing a simple program in C that I can pass a
lat, lon and get the elevation. I assume I need to open the .vrt f
