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GeoTIFF conversion to ECW/JP2 for use with Mappt

geotiff of satellite imagery shown over google earth map data

Satellite imagery and various forms of map data are commonly stored in GeoTIFF formats.

Which is your favourite Map data format? GeoTIFF, JP2, ECW? Is there any you can’t use in your current circumstances?

It is likely that you may have handled a variety of different GIS data formats throughout your career. Perhaps your company is migrating to a new software provider or changing their data management protocol. Or maybe you’ve just received a set of map data from an external source that’s in a different format to what you’re used to. For whatever reason, converting map data to different file formats is a regular activity in the life of a GIS professional.

Mappt is a mobile field mapping solution that allows you to utilise a great degree of flexibility in the types of contextual data that can be displayed. Map imagery data can be brought in to Mappt in either JP2 or ECW format. These formats bring a lot of advantages in their compressed file sizes and tiling features, which make it much easier to load imagery in smaller tiles for offline mapping. It is also possible to load very large, detailed maps in this format within Mappt, up to 1 gigapixel and beyond for Mappt PRO users. This grants the ability to view high resolution imagery even whilst using Mappt completely offline!

Given the popularity of GeoTIFF as a GIS data format, we decided to write a guide detailing how to convert these files to either ECW or JP2 file formats for the best use of Mappt.

Data conversion programs

In order to convert GIS files, special programs are usually required for new GIS formats to be written. A number of software programs are available to do so, and it is likely that your workplace will have access to at least one of them. For this guide, we will be using Global Mapper, which is a very useful and affordable program suitable to complete the file conversion.

global-mapper-featured

 

The first step here is to run Global Mapper and click on the folder icon to load your GeoTIFF data. Before this stage you should also check the projection of the data is correct for your workplace requirements. If it is not correct, change it in your regular GIS program beforehand.

Converting GeoTIFF data for Mappt

Once you have loaded the data in to Global Mapper, simply click File -> Export -> Export Raster/Image Format to begin the conversion process. A pop up will ask you to select a file type from a drop-down menu. It is here that you can select ECW, JP2 or otherwise depending on your requirements. Once selected, clicking OK will bring up the window shown below.

ecwconvert

 

In this window you can toggle the compression ratio, which will determine the final file size. For example, a lower ratio. eg 5:1 will result in a larger file than a ratio of 20:1. You can also select the metadata file formats to generate in this window, to match the program(s) you will be loading the data into following conversion. Everything else can stay at their defaults.

If you wish to clip the data at all, you can click on the ‘Export Bounds’ tab at the top of the window. Here you can click ‘Bounding Box’ to draw a custom box around the data you want included in the output.

Lastly, click OK to complete the conversion process and the program will ask you to specify a file name and location for the output.

Loading Imagery in Mappt

Once the above is completed, you will have your new data format saved on your drive and ready to load in to Mappt! To do this, you just need to send the data to your Android tablet running Mappt. You can do this via your preferred method (Email, Google Drive etc) and load it into your tablet’s filesystem. From here, follow the directions below within Mappt to load your data.

loadmappt loadecw

 

Now you should be equipped to convert and load imagery data into Mappt for your mobile mapping needs. Also remember that support is always available if you have needs beyond this tutorial. No question is a silly question when it comes to GIS! You can reach out any time at info@takor.com.au with any queries.

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