Extents - spectrum_spatial_analyst_1 - 23.1

Spectrum Spatial Analyst Guide

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Product family
Spectrum
Product
Spectrum > Spatial > Spectrum Spatial Analyst
Version
23.1
Language
English
Product name
Spectrum Spatial Analyst
Title
Spectrum Spatial Analyst Guide
Copyright
2023
First publish date
2007
Last updated
2024-07-30
Published on
2024-07-30T09:48:37.106910
This section provides help on how to specify map view properties like, zoom levels and pan-able extents and projection.

The Extents are the pan-able extents within which a user is allowed to pan. For example, if using Bing Maps, you can set pan-able extents to restrict users to panning within the New York area only and use the minimum zoom level to stop them zooming out to the whole world. The pan-able extents must be less than full extents that are set when you load a base map and specified in the same units (usually meters)

To set the map extents, follow the steps given below:
  1. Press the Shift Key on your keyboard and click on the map where you want to draw the extent. Now, drag the rectangle to draw the extent.
  2. You can pan and zoom into the panable extents.
    Note: By default, Bing Map is used as a map for extents.
Settings Description
Projection The coordinate/projection system for the map. You choose this by picking one of the base maps which will provide the projection for the Map Project. The other base maps and business maps can all be in different projections. Analyst will re-project them to match the projection that is chosen here.
North Extents The northern extent of the map up to which a user can pan.
South Extents The southern extent of the map up to which a user can pan.
East Extents The eastern extent of the map up to which a user can pan.
West Extents The western extent of the map up to which a user can pan.
Minimum Zoom Level Minimum Zoom Level for a map project can be set to a lowest value of 2. This is the most zoomed-out level for a map project. Level 1 is not available as it would always show a very small map tile with white space around it.
Maximum Zoom Level

Maximum zoom level for a map config can be set at 25. One important point to note is that, many Tile Service providers don’t support max zoom to 25. For example, Google Maps support max zoom of 21 only. In those scenarios, when the supported max zoom is less than the map config max zoom, Spectrum Spatial Analyst renders map for the remaining zoom level by stretching the map images on client side. Please refer to the table below for details on the max zoom for different Tile Map providers.

Bing Aerial, Bing Hybrid & Open Street Map 19
Bing Roads 20
Europa TMS 15
Google Maps 21
Any other XYZ or TMS layer 20
Spectrum Spatial Tile Maps Supported levels as defined
Initial Zoom Level The zoom level at which the map is displayed on start-up. This must be a number within the range of available zoom levels. The higher the number, the more zoomed-in the map will appear.
Search Zoom The zoom level that the map will zoom to when the Spectrum Spatial Analyst website visitor searches for an address/location. If the user searches for an address/location, they often want to view the surrounding area at a zoomed-in level, such as street level, which is a high zoom level number.
Zoom Level Descriptions The text labels that appear on the zoom slider to indicate which zoom level the user is viewing (For example, street view versus city view).
Display Units The distance unit used to display the results in the find my nearest results panel. You can select any values from the available drop-down list. For example, select meters/kilometers.
Repeat world horizontally

When this setting is enabled, Spectrum Spatial Analyst automatically repeats the world map horizontally (to make it appear seamless). It check the underlying data extents of the layers added from the mapping service and ensures that the data is rendered and queried correctly.

As a result, the data that goes beyond the world extents and the data that is originally inside the world extents are shown repeated and seamless.

Note: This behavior applies only to maps rendered from the Spectrum Spatial mapping service and to vector layers added by you. Maps rendered from the Tile Service, or any third-party services such as WMS, are still only displayed and queried for data lying within the usual world extents. For more information see, plotting geometries that cross the international date line.

Plotting geometries that cross the international date line

Spectrum Spatial Analyst can handle rendering and querying of data which goes beyond the international date line. For example, where the co-ordinates of the data exceed either +180 degrees in the east or -180 degrees in the west (or the equivalent in meters for other world projections).

This applies primarily to data in Russia and Alaska. Data from Russia sometimes has co-ordinates in the range of +180 to +192 degrees (rather than -180 to -168), since this shows the country as a single polygon in Precisely MapInfo Pro application. The same is true for some Alaska data where the islands off the west coast go beyond the date line to -187 degree.

Spectrum Spatial Analyst enables you to render eastern part of Russia or western islands of Alaska seamlessly. You can also perform query on the data using point or annotation tools.