Change Map Projection- Creating Coordinate Grids

Map projections define how (X,Y) coordinates in your data are displayed over images/maps used in the Map View.  Visokio applications allow you to calibrate or define coordinate grids on any kind of map, photo or scanned image imported for use as a map.

The Omniscope Map View Toolbar View Tools  menu (or the Configure Map View wizard in DataPlayer and FeatureFinder) includes a command Change map projection.  If your data is consistent with the default projection for your selected map (usually Mercator projections using decimal latitude and longitude fields (columns), you will not need to use this command.  However, if you are using a scanned image as a background map, or maps that are not consistent with the Mercator standard projection, you may need to tick the Override, by setting two reference points option.

This dialog allows you to configure and refine how coordinates in the data file will be positioned on your map.  There are 3 options:

1. You know  the coordinates of specific points on the image-for example, if you had imported an image of New York's streets and you had coordinates in some form of grid reference (such as latitude and longitude, which on a small scale are linear), and you knew the coordinates of two street intersections that were diagonally apart, you would use this dialog to ensure points in your dataset are plotted at the correct location. You would drag the two reference points to where you could see the two crossroads, then click the Change buttons to enter the correct coordinate locations for each crossroad.

2. You want the points distributed across the image- for example, you might have a data file of events during a game on a soccer pitch, and have imported a picture of the pitch to use as a map. You place corner events in two opposite corners of the pitch image. The coordinate system in your data file could be arbitrary, but assuming events happened across the entire pitch, you would click Distribute data points across map and the application would work out the transformation so as to "normalise" the points correctly.

3. You want the data points to map to the pixels in the image (default).  To revert to the default setting, where data coordinates correspond to pixel positions in the image, click 1:1 (pixel coordinates).

Back to Maps & Coordinates