At Nearmap we make all our vertical imagery available through WMS. Because WMS applications do not have universal support for temporal maps, we create a layer each time we fly an area. We call each of those flights a "survey". Our Australian WMS endpoint is organised in a hierarchical fashion with the following levels:
- Survey name
- Survey date
At every level of the hierarchy, a "latest" layer is available. For example "Australia latest" gives you the latest imagery throughout all of Australia.
Depending on the type of imagery that you need, you may want to use different layers.
Getting the latest imagery for the location
If you are interested in latest imagery of a location, just use one of the "latest" layers at a state level or above. This guarantees that you are seeing the most recent imagery for that location.
Getting imagery for a specific date
If you require better control over the imagery dates you will need to drill into the individual surveys. In regional locations this is pretty straight forward and at most you need to look in two folders - e.g. "New South Wales\Nowra" and "New South Wales\NSW.Nowra.00". In capital cities, this gets a bit more complicated as our survey names and footprints have changed over time. In order to help you to figure out which surveys you need, please refer to the following map -http://www.arcgis.com/apps/webappviewer/index.html?id=5e502bec8327497c963637d4cae78638.
The AU Surveys map is a snapshot of all of AU surveys from July 2016 and you can use it to discover which surveys are relevant for a given location. Please note that we will only refresh this map if the survey footprints change. We advise that you don't use this map to find out which survey dates are available. Because the survey footprints are quite stable now, we don't expect them to change too much in the near future.
Here are the steps for getting a list of survey names for a given location:
- Open the map.
- Search for a location
- Open the Selection widget
- Press select and drag out a small rectangle in your area of interest
- Click on "..." next to AU Surveys to reveal a menu and click on "View in Attribute Table"
- You now have all the surveys selected in the attribute table. This should give you an idea as to which surveys cover a location.
- (Optional) Feel free to export the surveys into a CSV files and perform some Excel magic to distill the list even further. Disclaimer, this is not an Excel tutorial.
- (Optional) Expand Options and click on "Export selected to CSV".
- (Optional) Open the CSV in Excel and create a pivot table with Name column being rows.
- (Optional) This gives you a deduplicated list of all the surveys that cover your area of interest.
You can also watch a short video that explains how to do lookup the survey names using the AU Surveys web map.