Converting Rasters and Vectors to Google Earth Images, using IDV

Marine Data Literacy 2.0

Providing instruction for managing, converting, analyzing and displaying oceanographic station data, marine meteorological data, GIS-compatible marine and coastal data or model simulations, and mapped remote sensing imagery

9.12 Converting Rasters and Vectors to Google Earth Images, using IDV

Exercise Title: Converting Rasters and Vectors to Google Earth Images, using IDV
Abstract: In this exercise you will learn how to convert typical raster and vector products in IDV to Google Earth images (i.e. rasters only). [The example products may have already made by you in the exercises cite below.] Essentially, any data product that can be produced in IDV -- raster or vector -- can easily be converted to a Google image. Raster-to-raster works flawlessly. True vector-to-vector conversion is not supported, but Google does a good job with vector-to-raster if the map isn't enlarged too much.
Preliminary Reading (in OceanTeacher, unless otherwise indicated):
- N/A
Required Software:
- IDV
Other Resources
- Integrated Data Viewer (IDV) Preliminary Setup
- sst_20101221_liberia_ghrsst_poet_esip_9km.nc - Raster image (NetCDF grid) of sea temperature made in 8.8 Viewing and Managing Well-Formed NetCDF Grids in Saga and IDV
- wind_vecs_jan_liberia_coads_nvods_saga_shp.zip - Vector plot (shapefile) of surface winds made in 6.2 Plotting Vector Arrows from U and V Component Grids with Saga
Author: Murray Brown
Version: 2-9-2015

1. This exercise shows you the basic steps to convert any visualization in IDV to Google Earth-compatible format. It does not cover all the many possible ways to control the exact appearance of the final product, e.g. colors, line properties, etc. You need to work these out on your own, using real-world cases.

2. Save the 2 example files to a suitable location on your PC. Do not unzip the shapefile; that's not necessary with IDV.

2. Run IDV - Latest version; properly set up.

3. Add data with DATA CHOOSERS > FILES and select the NetCDF grid.

Then click ADD SOURCE.

4. On the IDV dashboard, make these FIELDS and PLAN VIEW choices to see the raster.

Then click CREATE DISPLAY.

5. As usual with IDV you need to adjust the color palette to your favorite. Also, make sure to change the default data range (seen here) to the FROM ALL DATA choice, so it only covers the relevant values.

Just click the layer label in the right-hand menu to see your choices for palette and range.

6. You should see approximately this map, after you adjust the palette and data range.

7. Now, you can make the the Google Earth image. Just select VIEW > CAPTURE > IMAGE.

8. Navigate to PRODUCTS > IDV > KMZ (or similar). Then enter the filename sst_20101221_liberia_ghrsst_poet_esip_9km_nc.kmz

CAPTURE WHAT: Current View
QUALITY: High
BG Transparent: Check so that the black background around the IDV map is invisible in Google Earth.

Click Save.

9. To simplify matters, delete or "turn off" the raster image, using the tiny control at the far right side of the layers menu.

10. Now we can follow the same steps with the vector shape, but with a few optional other steps.

11. Load the shape, as you did above.

12. Make the display, as you see here. Notice that IDV can work directly with zipped shapes, so you don't need to decompress the file.

13. Here's the wind vector map. At this point you need to consider the color palette being used.

With rasters, it is easier, because you usually use only one raster per map, and overly vectors must be designed to be visible over them, e.g. black arrows on colored grids
With vectors, as you see here, it is a little more tricky because you must select colors that will be easily visible over the basic Google Earth maps/globes or easily visible over any rasters you also use.

The author won't try to show you all these tricks, and leaves it to you to work out on your own. He will show you the places in the process where you can make the adjustments needed for your own data.

14. Now, before we begin the image capture process, because this is for a vector you need to consider the color of the lines.

Use the IDV properties (click on the layer name in the LEGEND menu) to view and adjust the line 5/color, as you see here.

15. Another option is also presented for the color(s) of the saved file.

Select VIEW > COLOR to see some of your choices for the basic IDV map export. Make some experiments with your own data to see how these work.

16. Once you have selected the color(s) for the shape, then you can follow the same steps as above for capturing the image.

17. Save the image in PRODUCTS > IDV > KMZ with the filename wind_vecs_jan_liberia_coads_nvods_saga_shp.kmz

CAPTURE WHAT: Current View
QUALITY: High
BG Transparent: Check so that the black background around the IDV map is invisible in Google Earth.

Then click SAVE.

18. Now you have these KMZ images, they can be opened at any time in Google Earth, by simply double-clicking on them in file lists, or by use FILE > OPEN.

19. The raster file looks great, because you can completely control color in IDV, and it covers the Google globe completely, except where the BG TRANSPARENT setting has made it invisible.

20. The vector image isn't quite so good yet, because you need to do some work with the color palette, as stated above. That's up to you.

9.12 Converting Rasters and Vectors to Google Earth Images, using IDV