About the Land Mapper and Internet Connection Speeds
The Land Mapper accesses land status and other information that is stored in, and served from, ESRI's ArcGIS Online platform. The vector-based land status layers are approximately 4 GB in size, while the raster-based base maps can be anywhere from several hundred gigabytes to a few terabytes in size.
Because the Mapper is a web-based application, it uses your Internet connection to access huge datasets which are stored online. Even with the fastest gigabit connection, displaying a terabyte-size raster basemap in your browser would be unreasonably slow. The solution to this problem is to break up the data into smaller chunks, and for the browser to request only the chunks of data that are in the current display extent. These chunks, called tiles, are 256 x 256 pixels in size and are referenced by a row and column scheme. This is analogous to the rows and columns in an Excel spreadsheet, with each tile corresponding to a cell in the spreadsheet.
When you pan around the map and zoom in and out, your web browser requests the data it needs from the data servers. The request is for only those tiles within the current map display extent. Whatever is off-screen is ignored. This approach decreases the time needed to draw the map on the screen. To speed things even further, your web browser utilizes a cache. This cache is a temporary repository for data which has already been requested and displayed by the browser. It's purpose is to increase the apparent speed of your browser by supplying previously-requested data whenever you pan or zoom to a location you have already viewed in the Mapper. The increase in speed is due to the fact that accessing data from your local hard drive is significantly faster than accessing the same data via your Internet connection.
The More You Use the Mapper, the Faster it Becomes
The first few times you use the Land Mapper, it may seem unbearably slow, particularly if you have a slow Internet connection. Connections that rely on a series of satellites, as is typical with Internet connections in rural Alaska, will seem especially slow. Unfortunately, there is nothing the Division of Realty or your web browser can do about this. But all is not hopeless. Try zooming in to various scales, as this sometimes make the data layers load quicker. Additionally, the more you use the Mapper - panning around and zooming in and out - the more tiles will be cached on your hard drive. When you re-view an area you have previously viewed, your browser will utilize the cached tiles from your hard drive, and this may dramatically increase the responsiveness of the Mapper.
Web Browsers and the Cache
The Land Mapper has been tested in, and will work with current versions of Internet Explorer, Google Chrome, and Mozilla Firefox. Its functionality and appearance are identical in each of these browsers. Because the Mapper is based on Javascript and HTML 5, it will also work with other web browsers and mobile devices that can connect to the Internet.
Under normal use, you usually don't need to be concerned about your web browser's cache. However, there may be times when you need to clear the cache. This may be necessary if you are having computer problems or if you need to recover hard drive space by deleting temporary files. Uninstalling and reinstalling your web browser will also clear the cache. Clearing the cache has no effect on the functionality of the Land Mapper - after clearing the cache, the Mapper will work as expected. The only effect that clearing the cache has is that it deletes any cached tiles stored on your computer, thus when you start using the Mapper again, it will be a bit slower, as it has to download the tiles from the Internet again.
The Region 7 Land Mapper was developed, and is maintained by, the U.S. Fish & Wildlife Service, Region 7, Division of Realty. Questions, comments,and suggestions should be directed to ak_realty@fws.gov
This page was last updated: Thursday, March 13, 2025