Downloading larger areas of imagery now possible using the NC OneMap GeoPortal
8/4/2014 9:21 AM
Since the launch of the NC OneMap GeoPortal in 2012, one of the most heavily used features is the custom "download imagery" function. By clicking on the "Download Imagery" tab, visitors are able to define an area of interest on the map, choose the year(s), enter their email address, and then have all of the image tiles collected in a zip file which is made available for download. At the outset, we set the limit of tiles that could be downloaded at a single time to 20. One of the main reasons for doing this was to make sure that the server didn't get buried when we launched.
After a period of several months, we started receiving feedback that people needed to be able to select a larger area of imagery for their projects. After reviewing the logs, we determined that we could accommodate that and last year doubled the maximum number of tiles to 40 (~ 36 sq. miles). Now that we've had a couple of years to monitor demand for the updated imagery we feel fairly comfortable in projecting what the server will be able to handle when new imagery becomes available.
Which brings good news to those of you who have been needing or wanting to download larger geographic areas of imagery. We have again doubled the number of tiles that you can download at a single time. That means that now you can download up to eighty tiles (~ 72 sq. miles) for each available year.
Increase download size covers about 72 sq. miles or roughly 1/4 of the City of Charlotte
Just to give you an idea of what 72 sq. miles looks like, the graphic above shows the amount of imagery you could download for the City of Charlotte. With the increased download limits, you would be able to grab almost half of the City of Raleigh or a quarter of the City of Charlotte. We aren't making any promises but we will continue to monitor the server to see whether or not we can raise the maximum limit again. Of course, we still prefer that you use the image services whenever possible. We have a concise FAQ page that will get you up to speed quickly on how to use the services and which one is best for your scenario. However, if you need to download the imagery we hope this increased limit will better serve your needs.
As always, we look forward to your feedback so we can make NC OneMap work better for you.