Export reflectance values to Excell

PIX4Dmapper PIX4Dmapper Questions/Troubleshooting
1

I am flying fortnightly missions over a field trial site in Northern NSW, Australia. I am using an M600 with a Micasense Rededge camera. I have 81 regions plotted out and need to be able to graph the reflectance values obtained for each region from all these flights to see how they change over time so that I can compare treatments on the ground.

Is there a quick easy way to do this without either copying them by hand or having to use ArcGis as a proxy?

It would be a great feature for a future update!!

Any advice appreciated!

 

Cheers

 

Josh

2

Hey Josh,

There is an option to export index values as point shapefiles (average of 4 GSD’s) or the polygons. If you are looking for a specific region you could use shapefile of your area of interest then use the Intersection tool in QGIS to only include those points then export it and you can open it in Excel. Alternatively if you are looking for the whole region point shapefiles or the polygons would have the .dbf extension, which you could just open it in Excel and create a graph. 

3

Thank you for the response Selim. I opened the .dbf file in excel, but I am not quite sure what the data relates too. That is, the column headings are:

 

but there are 10 or more entries for each NDVI value adding up to over 300 ID’s.

Another thing: I changed the color scale to spectral and now all the color boxes next to the values are blank.

I created a region and tried to export again, but got the following error:

Processing]: Export range index

[Processing]: Downsampling

[Warning]: Warning w9020: GDAL error \<4\> Failed to open Shape DBF file `D:/pix4d/newer pix4d versions/Wollongbar PCU 140218/4\_index/indices/ndvi\Wollongbar PCU 140218\_index\_ndvi\_\_\_wholemap\_\_.dbf'.

[Warning]: Warning w9020: GDAL error \<1\> Terminating translation prematurely after failed

[Warning]: translation of layer contours (use -skipfailures to skip errors)

[Error]: Failed to generate: \<D:/pix4d/newer pix4d versions/Wollongbar PCU 140218/4\_index/indices/ndvi/Wollongbar PCU 140218\_index\_ndvi\_\_\_wholemap\_\_.shp\>

[Error]: Export range index failed!

[Error]: \>\>\>Export range index\<\<\< failed with error (failed to run a step!)!

[Error]: \>\>\>Export range index\<\<\< failed with error (failed to run a step!)!

 

Getting back to square one,

 

All I want to do is to create regions that relate to my plots on the ground, generate the reflectance values for each region (plot) and be able to compare them in Excel to relate that to my different treatments. Am I going about this the wrong way? Changing the color to spectral was just to try and make it easier to visualize.

4

Hey Josh,

I am not sure what is going on. The .DBF file is related to the metadata for the point shapefile or the polygons.  Another method that you could try would be using the the Clipper tool under Raster/Extraction in QGIS. You could create a shapefile for each of your region then clip them. But since you have a lot of regions it would be time consuming.