Downloading background maps
In circumstances where an Electronic Nautical Chart or CAD drawing of your survey area is not available, you can use the built-in background map download feature in Hydromagic. It allows you to use street maps or satellite imagery from Google, Bing or OpenStreetMaps as background (raster) image for your project.
The map tiles are downloaded from the provider of YOUR choice (Internet connection required, so it is recommended to prepare this in advance when you are in the office), and combined to form a map (raster)image, and geo-referenced to the projection you use in your project. Therefore you must select the map projection you will use before downloading any maps (during the creation of the Hydromagic project).
Please note that storing map tiles locally breaks the terms of service for a couple of popular data providers like Google, Bing, and ArcGIS Online. Use this function at your own risk! Since OpenStreetMaps does not have these limitations, it is safe to use.
Map downloading tool
To start the map downloading tool, right-click the 'Maps' folder in the 'Project Explorer' and select the 'Download Map...' option from the pop-up menu, as shown in the image below. Alternatively, you can select the "Download Map..." option from the "File" menu.
The map downloading tool can be started from the Project Explorer.
The background map download tool allows you to download street maps or satellite imagery from the following providers:
- OpenStreetMaps;
- Google;
- Bing (Virtual Earth);
- Nokia OVI maps;
- MapQuest maps;
- ArcGIS map service.
Setting area and options
In order to download maps, you have to select the area you need a map for, and which provider you want to use. Use the "Information Source" selection box to select the provider and the type of map (street, satellite or hybrid).
The next step is to select the area. Select the smallest area as possible, because the smaller the area, the higher the zoom level and level of detail. You have to enter the upper-left and lower-right WGS84 coordinates of the area you are surveying in.
Because the maps are downloaded as 256 x 256 pixel image tiles, it is likely that the actual downloaded area is a bit larger then the requested area. You can obtain the coordinates by using a map viewer like Google Earth or others, or use the "Area selection tool" which is discussed in the next paragraph.
Finally, select the name of the output file (the file where the map is stored) and whether to add the map to the project directly. Depending on the type of map you are using, the image is stored as PNG (Portable Network Graphics) or JPG (JPEG-Compressed) file.
The build-in background map downloading tool allows you to download
and import a map for almost any location on the globe.
Area selection tools
As an alternative to manually entering the coordinates, you can calculate the map boundaries from a waypoint, raw data file, sounding, boundary, current location, or an address. To do so click the "Calculate..." button. The following dialog will appear:
The map downloading tool offers multiple options to determine the map area.
The first three options (GPS Position, Address and Waypoint) can be used to specify the center of the map. To calculate the map extends, you have to enter the map dimensions. When using one of the last three options (raw data file, sounding or boundary), the map dimension entries are disabled, and the boundaries are copied directly from the area covered by the selected file, sounding or boundary.
Please note that when using the 'Find Address...' tool, make sure you are connected to the Internet to perform a Geo-Coding lookup. When facing problems with the address lookup tool, click the "Show Log..." button to get more detailed information on the problem.
You can use a street address as center of the map download area.
Download
To start downloading, just click the "OK" button. Please note that you have to be connected to the Internet at this moment. The download progress is shown in the status bar. The download time varies per provider, but should be between the 15 seconds and 2 minutes. Please be patient when the tool doesn't seem to be responding, this can happen when data is coming in slowly.
First, the tiles are downloaded and merged into larger images, which are geo-referenced using the projection set. When downloading has been completed, and if the 'Add downloaded map to the current project when completed' option has been checked, the map will be added to the current Hydromagic project and displayed.
Troubleshooting
When a map download fails, make sure that your Internet connection is working. If this is the case, try whether you can download a map from a different data source. You click the "Download" tab of the Activity View to get more information on the issue:
Download progress and issues will be displayed in the activity view.