Mango supports rendered raster images with embedded geo-referenced data.

 

Whether you're working with high resolution drone imagery, georeferenced scans, or satellite and aerial acquired imagery, Mango's raster support enables many use cases from cadastral survey to agricultural monitoring to engineering and construction.

 

Related tools

• Scale range - increase the default scale range to allow deeper zooming of raster data
• Sketch - a highlighter for your maps. Draw, annotate and share.
• Add vector features - digitise new features on top of raster imagery right from within Mango.
• Edit vector features - edit geometry and attributes of existing overlay data.
• Custom legend - add a custom legend for your raster layer.

 

Requirements

File format

• Mango supports GeoTIFF raster imagery containing georeferenced data with the .tif extension
• A zip file must be uploaded, it needs to contain exactly one .tif file.
• Mango does not support world files .tfw, or rasters using the .tiff extension

Zip Compression

GeoTIFF files must be compressed to a .ZIP archive before uploading to Mango.

• The raster must be no larger than 2 GB when uncompressed.
• The raster must be no larger than 1 GB when compressed.

RAR compression is not supported at this time.

Raster Compression

All rasters are decompressed during processing for tiling purposes. If your GeoTIFF has compression applied (e.g. Packbits, LZW, or Deflate), it will use more of your storage quota in Mango that it does on your system. 

If your raster is larger than 2 GB uncompressed or 1 GB when zip compressed, the file must be split and uploaded as separate sections and each section uploaded individually.

Bands

• 4 band rasters with an alpha channel is supported if captured from UAV
• 4 band rasters sourced from satellite imagery must be converted to 3 band rendered image

Resolution

Mango's maximum zoom level is z22, which translates roughly to a scale of 1:106. Most drones and orthophoto stiching applications can produce rasters with a resolution that is higher than Mango can display, leading to file sizes which are larger than necessary and limits the coverage area possible in a single raster.

When preparing raster data for upload to Mango, we highly recommend reducing the resolution to optimise for the maximum zoom level. This will minimise the file size and therefore maximise the coverage area that can be supported before tiling the raster into smaller parts is required for upload to Mango.

In QGIS, note the existing resolution in the export panel. The file size at native resolution with no TIFF compression is 722.2 MB.

Before: original raster resolution

Adjust the resolution incrementally and test exports until you find the sweet spot. A reduction of ~50% is often possible without loss of quality at z22/1:106 scale. The file size at this resolution with no TIFF compression is 230.2 MB, a 68% reduction.

After: reduced raster resolution

 

Common rendering issues

Black & White Pixels

When you upload your raster, Mango will automatically make black (0,0,0) pixels transparent, which usually represent No Data. 

If you do not want transparency on black No Data pixels, you can:

• Upload a background polygon and add it as a layer underneath the raster layer, and set the fill colour it black using the basic style.
• Replace the pixels with a value of 0 to 1, and upload the new version to Mango.

If your data has white (255,255,255) pixels that you wish to make transparent, please convert these to black pixels using a desktop GIS before uploading to Mango.

Colours don’t look right after upload

For images that contain original measurements such as elevation models and un-enhanced satellite imagery, default styling and contrast stretching will be applied by Mango. In the case of single band imagery, this will be a black to white color ramp. If you wish to control the colours and contrast, you will need to prepare your image in a Desktop GIS prior to upload.

ArcGIS & ArcMap

1. In layer properties → Symbology, set the colors and contrast stretch as you would like them to appear.
2. Right click the layer and choose Data → Export data and set the options for Use Renderer, Force RGB, and NoData as shown in the example below. 

If the export to TIFF does not work, try exporting to ERDAS .img format, then take the ERDAS .img file and export to TIF, without the “Use Renderer” option.

QGIS

1. Set the colors and contrast stretch as you would like them to appear.
2. Right click the layer and choose “Save as..”

Set the options as shown in the example below.

 

Need a legend? Here's how:

How to add a legend to symbolized raster data

 

Common GeoTIFF Upload Errors

Your GeoTIFF may fail to upload if:

Your raster is four band satellite imagery 

If your raster is sourced from satellite, it will usually contain four bands. You may find that it appears black and white in Mango, or fails to upload entirely. In this instance, you will need to create a rendered image with only three bands and upload the new raster to Mango.

ArcGIS™

Export the raster and choose Use Renderer and Force RGB to create a three band image (see instructions above).

QGIS

1. Run OSGeo4W Shell
2. Navigate to the directory where your data is
3. Type the command:
   gdal_translate -b 1 -b 2 -b 3 input.tif output.tif
4. Zip and upload the new TIF file to Mango

 

You do not have a coordinate system defined

ArcGIS™

Check to see if a coordinate system is defined:

To set the coordinate system use the “Define Projection” tool

QGIS

You will be asked to set the coordinate system (CRS) when you add the raster to the project. To apply the CRS to the image permanently, right click on the layer and choose Save As.

 

The .zip file contains a folder

Zipped rasters will fail to upload if the .tif is contained within a folder inside the zip archive. Place the raster in the root and remove any folders from the zip archive before uploading.

 

Known issues

Floating point (decimal) rasters where the null value is set to a large negative number is known to cause upload issues.