(handle));
interactor->Start();
```
and this is what im trying to get
the image is taken from panoply
---
### Author:  [@sankhesh](https://discourse.vtk.org/u/sankhesh)
#### Post date: [July 14, 2023, 3:52am UTC](https://discourse.vtk.org/t/vtk-rendering-satellite-data-from-netcdf-file-in-c-error/11930/2 "2023-07-14T03:52:26Z")
The error indicates that the variables in your data are all not the same length. I can see in the mock image you shared that the variable only spans over a portion of the whole region. I don’t know much about the netcdf spec but if this use-case is valid, the reader needs to be changed to accommodate it.
---
### Author:  [@Cave1212](https://discourse.vtk.org/u/Cave1212)
#### Post date: [July 14, 2023, 4:06am UTC](https://discourse.vtk.org/t/vtk-rendering-satellite-data-from-netcdf-file-in-c-error/11930/3 "2023-07-14T04:06:20Z")
@sankhesh What do i need to change?
---
### Author:  [@sankhesh](https://discourse.vtk.org/u/sankhesh)
#### Post date: [July 14, 2023, 2:16pm UTC](https://discourse.vtk.org/t/vtk-rendering-satellite-data-from-netcdf-file-in-c-error/11930/4 "2023-07-14T14:16:34Z")
@Cave1212 My guess is that the dataset you’re trying to load has more points than scalars. The warning you see originates from [https://gitlab.kitware.com/vtk/vtk/-/blob/master/IO/NetCDF/vtkNetCDFReader.cxx#L838-858](https://gitlab.kitware.com/vtk/vtk/-/blob/master/IO/NetCDF/vtkNetCDFReader.cxx#L838-858)
which essentially means that there is a mismatch between number of points and point scalars. If your use case allows for this, the reader would have to set `0` values to the points where there are no scalars.
---
### Author:  [@Cave1212](https://discourse.vtk.org/u/Cave1212)
#### Post date: [July 14, 2023, 3:32pm UTC](https://discourse.vtk.org/t/vtk-rendering-satellite-data-from-netcdf-file-in-c-error/11930/5 "2023-07-14T15:32:41Z")
@sankhesh also do you know how to get the noise data from a netcdf file i do have color mapping but the colors and the color positon is always the same for different netcdf files but when i open the file in panoply the colors and color position are different
this is the code i have
```auto
float scalingFactor = 1.0f / 2.122f;
glEnable(GL_QUADS);
glShadeModel(GL_SMOOTH);
vtkSmartPointer mapper = vtkSmartPointer::New();
vtkSmartPointer data = vtkDataSet::SafeDownCast(reader->GetOutput());
glPushMatrix();
glRotatef(-90.0f, -10.0f, -10.0f, -43.0f);
double minNoiseValue = std::numeric_limits::max();
double maxNoiseValue = std::numeric_limits::lowest();
for (vtkIdType i = 0; i < data->GetNumberOfCells(); i++) {
vtkCell* cell = data->GetCell(i);
vtkPoints* points = cell->GetPoints();
if (cell->GetNumberOfPoints() == 4) {
for (int j = 0; j < cell->GetNumberOfPoints(); j++) {
double noise[3];
points->GetPoint(j, noise);
double noiseValue = noise[0];
minNoiseValue = std::min(minNoiseValue, noiseValue);
maxNoiseValue = std::max(maxNoiseValue, noiseValue);
}
}
}
vtkSmartPointer colorTransferFunction = vtkSmartPointer::New();
double noiseRange = maxNoiseValue - minNoiseValue;
double color1[3] = { 0.0, 0.0, 1.0 }; // Blue
double color2[3] = { 1.0, 1.0, 0.0 }; // Yellow
double color3[3] = { 1.0, 0.0, 0.0 }; // Red
double color4[3] = { 1.0, 1.0, 0.0 }; // Yellow
double color5[3] = { 0.0, 0.0, 1.0 }; // Blue
double noiseValue1 = minNoiseValue;
double noiseValue2 = minNoiseValue + noiseRange * 0.25;
double noiseValue3 = (minNoiseValue + maxNoiseValue) / 2.0;
double noiseValue4 = minNoiseValue + noiseRange * 0.75;
double noiseValue5 = maxNoiseValue;
colorTransferFunction->AddRGBPoint(noiseValue1, color1[0], color1[1], color1[2]);
colorTransferFunction->AddRGBPoint(noiseValue2, color2[0], color2[1], color2[2]);
colorTransferFunction->AddRGBPoint(noiseValue3, color3[0], color3[1], color3[2]);
colorTransferFunction->AddRGBPoint(noiseValue4, color4[0], color4[1], color4[2]);
colorTransferFunction->AddRGBPoint(noiseValue5, color5[0], color5[1], color5[2]);
for (vtkIdType i = 0; i < data->GetNumberOfCells(); i++) {
vtkCell* cell = data->GetCell(i);
vtkPoints* points = cell->GetPoints();
if (cell->GetNumberOfPoints() == 4) {
glBegin(GL_QUADS);
for (int j = 0; j < cell->GetNumberOfPoints(); j++) {
double noise[3];
points->GetPoint(j, noise);
double noiseValue = noise[0];
double color[3];
colorTransferFunction->GetColor(noiseValue, color);
glColor4f(color[0], color[1], color[2], 0.5);
float lon = points->GetPoint(j)[0];
float lat = points->GetPoint(j)[1];
float altitude = points->GetPoint(j)[2];
glVertex3f(lon * scalingFactor, lat * scalingFactor, altitude * scalingFactor);
}
glEnd();
}
}
glPopMatrix();
```
---
### Author:  [@sankhesh](https://discourse.vtk.org/u/sankhesh)
#### Post date: [July 17, 2023, 1:23pm UTC](https://discourse.vtk.org/t/vtk-rendering-satellite-data-from-netcdf-file-in-c-error/11930/6 "2023-07-17T13:23:36Z")
> [@Cave1212](#):
>
> ```auto
> double noiseValue = noise[0];
>
> ```
@Cave1212 In the code you posted, you are just using the X coordinate of the points as `noise`. To get the range of values in the data, you can just do something like
```cpp
double* noiseRange = data->GetPointData->GetArrayByName("")->GetRange();
```
Change `` to the name of the variable that represents noise in your dataset. Hth