The Multispectral Product Database
On this page, you will find general help for the ProRaster product family including links to documentation, instructional videos, and training videos.
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You interact with product databases via the “Browse Products” menu button.
Drop down the menu button to reveal the options for creating and deleting product databases.
Creating a product database
Create a new product database by selecting “Create new product database”. You need to create and name your new product database. Your database must have a unique name. The product database file will use this name. If the name is unique then you will see a green tick. Hit OK to create the product database.
You can create as many product databases as you want. How you organise your products is up to you. You may want to add all products to a single large database, or you may want to create a database for each project that you undertake.
- A product database file has a “<your name>.msspdb” file name. You must specify the name when you create the database. You cannot change the name thereafter.
- Every product database you create will be located in the “C:\Users\<your user name>\RGE\Satellite” folder on your main drive. You cannot move this file.
- When you create a product database it creates a new folder in the “C:\Users\<your user name>\RGE\Satellite” folder of the same name. For example, if I create a new product database called “PDB_KatiThanda.msspdb” then a new folder “C:\Users\<your user name>\RGE\Satellite\ PDB_KatiThanda” will be created. If you have matching scene and product databases for projects, it is a good idea to differentiate them with some naming prefix like SDB_ and PDB_.
- The new folder will contain all the MVR virtual raster files and all other files that are created for every product in the database.
- When you delete a database both the .msspdb file and the folder and all its contents will be deleted.
You can delete individual products from a product database (in the product browser) or delete the entire database. In the first case, all of the output files generated by the product will be moved to the recycle bin. In the second case, both the .msspdb file and the entire output folder will be moved to the recycle bin.
Browsing a product database
Click on the Browse Products button to open a browser for a product database. If you have more than one product database, then a dialog will open allowing you to choose which product database you wish to browse. Double-click on the database in the list or select the database and hit OK.
The product database browser is very much like the scene database browser. It contains a world map showing the bounding box of each product in the database and a spreadsheet containing the products.
The primary purpose of the product browser is to select a product for editing. Double-click on a product to open the multispectral product editor for that product, or right-click and select “Edit Product”.
Right-click on a product and select “Delete Product” to delete that product from the database. The product will be removed from the database. Optionally, all the output files generated by the product can be moved to the recycle bin.
Creating a product
In the same way that you can select multiple scenes in the scene browser and create a new product from those scenes, so too can you select multiple products in the product browser and create a new product from those products. The new product is written into a multispectral product database and can be edited using the multispectral product editor dialog.
From the product database browser, you can make four types of advanced products.
This is an alternative way to produce a scene sequence product. You can also do this from the scene browser where you select the scenes directly. The selected products must be spectrally compatible. Select two or more scene products in the database and right-click to create a scene sequence product.
Collated Scene Sequence
A collated scene sequence brings multiple collated scene products together into a sequence. The selected products must be spectrally compatible. It is also likely that each collated scene product will use the same mask band. Select two or more collated scene products in the database and right-click to create a collated scene sequence.
Spectral compatibility means each scene has the same Platform, Family, Processing, Processing Level, and Product. It not only ensures that data is comparable across scenes, but it also ensures that the field and band structure of the rasters is the same. This is a critical issue for virtual raster construction. Here is an example for Landsat.
Family Landsat 8 & 9
Processing Collection 2
Processing Level L2SP (Level 2, Surface reflectance and temperature)
Product Level 2
Spectral compatibility for Sentinel 2 is easier to achieve as you only need to make sure that all your scenes are either Level 1C or Level 2A.
Consider an example using Landsat 8 & 9. Each bird revisits each tile every sixteen days, and the orbits are staggered so that each tile on the Earth is revisited by a bird every eight days, or four times per month. Each individual scene is likely to be affected by cloud cover, so to build a more complete dataset with the most high-quality pixel coverage, you choose to collate the four scenes for each month into a collated scene. You sort the scene based on proximity to the middle of the month, so each collated scene is the best representation of the Earth in that tile on the 15th of the month. Having started with four data values for each pixel (one per scene), you now have only one data value per pixel.
Over a period of a year for this tile, you build twelve collated scenes, one for each month of the year. You can then bring those together into a sequence, allowing you to visualise the temporal changes easily and to perform the same data analysis on each collated scene in the sequence. Ultimately, you will compute statistics for this dataset and build up a quantitative picture of how various measured parameters have changed over the course of that year.
A mosaic sequence brings multiple mosaic products together into a sequence. The selected products must be spectrally compatible. Select two or more mosaic products in the database and right-click to create a mosaic sequence.
When you are combining tiles into a mosaic, it is a more difficult challenge to acquire scenes that are approximately contemporaneous. Tiles in a north-south direction lie along the bird’s orbit and are collected in sequence, but tiles to the east and west (which lie on a different orbital path) may be surveyed days earlier or later. In the case of the Landsat 8 & 9 family and the Sentinel 2 family, tiles on different orbital paths may be separated by up to eight days.
It is likely that your mosaic will be affected by cloud cover and that this may vary substantially from one tile to the next. If you plan to use the mosaic for data analysis, you may wish to mask the cloud out in the product editor, which will reduce the coverage of your dataset.
Collated Mosaic Sequence
A collated mosaic sequence brings multiple collated mosaic products together into a sequence. The selected products must be spectrally compatible. It is also likely that each collated scene product will use the same mask band. Select two or more collated mosaic products in the database and right-click to create a collated mosaic sequence.
To improve the quality of the data in a mosaic, you can combine repeat observations of one, or more, or all tiles in the mosaic. For example, if you were to gather all the scenes collected over a period of a month for a mosaic of tiles, then you can collate them and collapse the dataset to a single value per pixel, with a higher percentage of quality data. This is a collated mosaic. If you were to do this for every month in a year, you can then bring those twelve collated mosaic datasets together into a sequence.