Guidelines for defining an AOI
When defining an area of interest for your export, there are a few guidelines you need to follow to ensure the area is valid.
There are two ways to define an area of interest for export in MapBrowser:
- Drawing the area directly onto the map
- Importing a GeoJSON file - only 3D can be exported with this method.
Defining the area
The area you have defined is invalid if:
- You have drawn an invalid shape
- You have uploaded an invalid file format. To resolve this error, you will need to modify the GeoJSON file.
- Your GeoJSON file is defining features that are invalid.
You'll see the error shown here.
Bounding box
The area you have defined will result in the following error if the number of points in the bounding box around the area exceeds 1000.
File Format
MapBrowser supports uploading a file in the following two formats:
Uploading files is any other format will result in the error shown here.
Coordinate system
Ensure that your JSON or GeoJSON file is specified in WSG84 coordinate system. You will see the error shown here if you use any other coordinate system.
TroubleshootingValid Shapes
You can upload GeoJSON files that define areas of interest containing:
- Polygons and multi-polygons
- Holes within geometries
The example below shows an uploaded GeoJSON file containing both multi polygons and holes within polygon.
Example of an invalid shape
A self intersecting polygon has sides that cross over, like the one shown below, is an invalid shape.
Modifying the GeoJSON file
This error indicates that your JSON or GeoJSON file contains one or more of the following:
- Feature Collections, LineStrings, Points etc
- Empty geometries
- Self Intersecting Polygons
Check your GeoJSON file and if it contains any of these features, you will need to modify it.
Feature Collections, LineStrings, Points etc
{ "type": "FeatureCollection", "features": [ { "type": "Feature", "geometry": { "type": "Point", "coordinates": [102.0, 0.5] }, "properties": { } }, { "type": "Feature", "geometry": { "type": "LineString", "coordinates": [ [102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0] ] }, "properties": { } }, { "type": "Feature", "geometry": { "type": "Polygon", "coordinates": [ [ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ] ] }, "properties": { } } ]}
The above example from https://en.wikipedia.org/wiki/GeoJSON.
Empty geometries
Example 1
{ "type": "Polygon", "coordinates": [] }
Example 2
{ "type": "MultiPolygon", "coordinates": []}