Custom Maps can be used at least for the following purposes when suitable maps have been downloaded to or created on the phone. Please ensure that you have the necessary rights before copying, distributing, or using a map image in Custom Maps.
If you come up with other creative ideas for using Custom Maps, let me and everyone else know through mailing list link in the sidebar on the left.
Custom Maps does not store user location information, and when the app is used to view maps it does not use or need any kind of internet connection. It only needs a GPS signal from satellites. The app uses internet connection only when new maps are being created.
Android limits the size of memory used by any single app. This amount of memory depends on the device and the version of Android. All devices should be able to open images up to 3 megapixels in size, for example 2000x1500. You can check the maximum image size your device can handle on the settings screen inside the Custom Maps app.
Notice that some phones can take photos that are larger than the largest image size Custom Maps app can handle. If that is the case, you can change the camera settings to take 3 megapixel photos, and take another picture to be used for the map.
It is possible that the map image in the shared map is too large for your device (see previous question). Check the largest map image size supported by your phone in the settings screen, and let your friends know not to share larger maps with you. If you are sharing maps with your friends, it is better to limit the map images to 3 megapixels, so that all devices should be able to open them.
Read the tutorial for creating maps. The link to the tutorial can be found also on the left sidebar throughout this web site. Below is a condensed summary.
It is relatively simple to create your own map using Custom Maps. Just follow these steps.
Unfortunately not directly. But there are a couple of workarounds. Simplest is to display the PDF map on your computer screen and take a photo of it with your Android phone. Then follow the instructions above to create a map out of that photo.
If you are willing to do a bit more work for higher quality map image, you can open the PDF on your computer and either take a screen shot of the displayed PDF map (with print screen button) or if your PDF viewer supports it, save the PDF as a JPG file (at least Preview application on Mac OS X does support this). Make sure the image size does not exceed the maximum recommended resolution listed on the Settings display in Custom Maps app. Then you need to transfer the resulting image to your phone's SD card, and then you can follow the instructions on the previous question to create a map out of that image.
Usually two points are enough, and sometimes when the map image is not drawn to scale very well, a third point can make the map fit worse than just two points. On the other hand, well selected four points close to map corners can make a map work better (especially when photographs are used), but not all maps can be aligned. Also, sometimes some features of the map are misaligned worse than others, and sometimes it pays off to remove a tiepoint and replace it with a different one. The program allows adding more than four points, but only the first four points are used by the app. Points can be adjusted or deleted by tapping and holding (aka "long-pressing") a point in the list.
Yes, Custom Maps includes "Share map" option in the application menu which can be used to send a map to your email contacts. Sending and receiving maps requires naturally a working internet data connection (wifi or cellular data). Do not share maps unless you possess the necessary rights to do so.
I found a .kmz map file in the internet that looks nice. Is there any way I can check if it is properly aligned before I go out and use it?
Yes. When you are selecting the map, "long press" it (hold your finger down on it until a menu pops up) and select "Modify map" from the menu. In the "Modify map" activity you can rename the map or change the associated comment, and in preview screen you will be able to see how well the map lines up with Google Maps data (both road map and satellite). If the alignment does not look good enough for you, you can return back to previous screen and try to adjust the tiepoints used to match map image features with geo-coordinates (and Google Maps). They can be adjusted by long pressing the points in the list. Notice that many map images are not geographically accurate, and cannot be aligned perfectly with reality. They can still be useful as maps showing you the approximate area where you are located. Use your judgement when using Custom Maps.
Android phones limit the amount of memory each application can use, and large images like maps take a lot of memory to display. All Android phones should be able to display map images up to 3 megapixels in size, and some of the newer phones with lots of memory and new operating system versions can display map images that are 5 megapixels in size. If you plan to create a map for sharing with other people, you should consider limiting yourself to map images that no larger than 3 megapixels. You can find out what the largest recommended image size for a specific phone is by opening the Settings page in Custom Maps.
Custom Maps uses .kmz files for storing its maps. They are zip-formatted .kml files that can contain additional resources like images (KML is short for Keyhole Markup Language, named after the company who created the file format). The .kmz files used by Custom Maps app are typically not compressed since jpg and png image files don't typically compress almost at all, and the data files assigning the geographic coordinates to the map images are so small that they don't really benefit from compression. Uncompressed files can also be processed faster by Custom Maps, but it can handle compressed files as well (not password protected .kmz files though).
Should Custom Maps be able to use any .kmz file? I found a .kmz file on the web that I cannot open with it.
Custom Maps can not display all .kmz files. For Custom Maps to be able to open and display a .kmz file, the file must define an image overlay (aka GroundOverlay), and the image must be stored inside the same .kmz file. There are many .kmz and .kml files on the web that either contain no image overlays, or the image overlays specify that the map image is stored somewhere in the web. Since Custom Maps is designed to work offline, it does not even attempt to follow web links. Such kmz and kml files can be displayed usually only with Google Earth application on a desktop computer.
I have created a map from an image I have rights to distribute. I want to post a QR code for others to scan and download it from my web site. What should the QR code contain?
The QR code should contain a URL in format http://www.custommapsapp.com/qr?url=<actual-map-file-url>
For example, the QR code for the sample map of Europe contains this URL: