Map Suite WebAPI Edition supports many popular GIS file formats. In this learning sample we will go over some of the most common supported GIS data formats and also discuss the concept of a layers and how they are used to create maps.

A layer is a visual representation of geospatial data. You can think of layers much like actual terrain in the real world. The bare earth might be a layer and have either physically defined boundaries, such as a fence around a military installation, or legal boundaries, such as the border of a country. Another layer on top of that might be roads that are built upon the bare earth. It is important to understand this when working with layers, as they need to be added in the logical order you might expect so that they can be visualized correctly from above. In other words, you would not want to lay down roads and then cover them with earth, because they could not be seen or used by vehicles.

There are three types of layers that are supported by all editions of Map Suite: Vector, Raster, and Web-Based. Vector is one of the most popular GIS data formats and may contain points, lines, and polygons. It is useful for storing data that has discrete boundaries, such as country borders, land parcels, and streets. Raster data contains a matrix of pixels and is used for digital images such as aerial imagery, floor plans, or topographic maps. Web-based data comes in a variety of forms. It could be basemaps served by Google or Bing. It could be data such as NOAA weather information. Check out the Map Suite Data Format Guide to see all the formats that are supported by Map Suite.

In this learning sample we will go over some of the most popular types of of layers:

Vector

• Shapefile
• TAB
• TinyGeo
• FileGeoDatabase
• SQLite
• WKB
• KML
• MapShape
• InMemoryFeature

Raster

• MrSID
• JPEG2000
• GeoTIFF
• BMP/PNG/GIS/JPG/Tiff

Web Service

• NOAA Radar
• NOAA Weather Station
• WMS

There is also a customized layer that contains custom vector data to demonstrate the extensibility of Map Suite and how you can integrate almost any type of data format.

In order to better manage layers and to benefit from caching layers may be grouped as overlays. All layers in an overlay will generate one bitmap. Caching occurs at the overlay level where the bitmap is generated.

The order of your layers is very important and will determine what is visible. You would create and add layers based on how they should be viewed, so naturally you might start with some polygons, such as the outline of a country and all of the regions within it. You might then lay down lines that represent rivers and roads and then finally you might lay down points like cities or places of interest. Again, keep in mind that logic will dictate what works best. For instance, laying down roads and then rivers would put rivers on top of roads when it should more than likely be the other way around (the exception here might be a tunnel!).

There are two projects in the Visual Studio solution. One is for the Leaflet javascript mapping library and one is for OpenLayers. In each project the LayersController contains the function that loads each layer type. Each function is prefaced with the type of layer. At the bottom is InitializeProjection which sets up the map projection and DrawTileImage which draws the Layer Overlay bitmap. The App_Data folder contains data for each of the layer types.