Raster Data Sources
Raster data sources are used to access raster spatial data (images). See the following sections for information on the various types of raster data sources that are supported.
| ECW - JPG2000 | JMap Server |
| GDAL - Geospatial Data Abstraction Library | OpenStreetMap |
| TIFF - GEOTIFF | WMS Server |
| ArcGIS REST | WMTS Server |
ECW - JPG2000
With this type of data source, it is possible to read ECW or JPG2000 image files or to connect to an ECWP server (ERDAS Image Web Server) to obtain images. It is not possible to configure both at the same time.
| Parameters | |
|---|---|
| Selected files | Select one or more ECW or JPG2000 image files to read. If many files are selected, they will be considered as a mosaic. The files must be georeferenced. |
Note: This type of data can also be read by the GDAL data source with the same performance. This data source is kept for compatibility with existing configurations.
GDAL - Geospatial Data Abstraction Library
This type of spatial data source allows you to read a wide variety of raster data formats. GDAL (Geospatial Data Abstraction Library) is an open source library specializing in raster data conversion and processing.
There can be one or more source image files (mosaic of images). The images of the mosaic can overlap and there can be holes in the mosaic.
When the data source is updated, if the option is activated, a pyramid of lower resolution images is created by JMap Server and stored in the image cache. The image cache is then used for high performance production of images on the fly at specific resolutions. Depending on the initial image sizes and parameters, the image cache size can become voluminous. Typically, the total image cache is about the same size as the original images. Available disk space must be sufficient before updating this data source. It is possible that the data format selected will not require the creation of a pyramid. In this case, the parameter will be ignored.
| Parameters | |
|---|---|
| Selected files | Select one or more image files to read. If many files are selected, they will be considered as a mosaic. The files must be georeferenced. |
| Cache path | The directory where JMap Server will store generated image files for the various resolutions. Default is JMAP_HOME/cache/raster. |
| Image interpolation | Method for producing images with reduced resolutions from images with higher resolutions. Default is Cubic and this method usually produces the best results. |
| Compute statistics (may take some time) | Statistics on image pixels simplify the analysis of these images. JMap extensions such as JMap Imagery use these statistics to work. Calculating statistics can take several minutes and this option should only be activated when necessary. If you do not need statistics, do not enable this option. |
| Create a pyramid | Activates the creation of an image pyramid with several resolutions. This greatly improves performance for producing images on the fly. |
| Pyramid image interpolation | Method used to produce pyramid images. The default value is Cubic and this method usually produces the best results. |
TIFF - GEOTIFF
This type of spatial data source can read georeferenced TIFF image files. JMap supports two types of georeferenced tiff images: tiff files with tfw files (the tfw files contain georeferenced data) or geotiff files (georeferenced data inside image file).
There can be one or more source image files (mosaic of images). The images of the mosaic can overlap and there can be holes in the mosaic. When the data source is updated, lower resolution images are created by JMap Server and stored in the image cache (pyramid of images). The image cache is then used to produce images on the fly at specific resolutions with optimal performance. Depending on the initial image sizes and parameters, the image cache can become voluminous. Typically, the space used by the cache is the same size as the original images. Available disk space must be sufficient before updating this data source.
Note: This type of data can also be read by the GDAL data source with the same performance. This data source is kept for compatibility with existing configurations.
| Parameters | |
|---|---|
| Selected files | Select one or more image files to read. If several files are selected, they will be considered as a mosaic. The files must be georeferenced. |
The other parameters don’t need to be modified most of the time.
| Reader options | |
|---|---|
| Cache path | The directory where JMap Server will store generated image files for the various resolutions. Default is JMAP_HOME/cache/raster. |
| Interpolation type | Method for producing images with reduced resolutions from images with higher resolutions. Default is Bicubic and usually gives the best results. |
| Compression type | Type of compression of the lower resolution images in cache. Default is None and offers the best performances but uses more disk space. |
| Resolutions | |
|---|---|
| Resolutions | Number of lower resolution images to prepare and resolution ratio in relation to the higher resolution images. Default is 8 with each image resolution divided by 2. All these resolutions form the pyramid of images. |
ArcGIS REST
JMap Server can connect to ArcGIS Server and ArcGIS Online REST services to access WMTS-type raster data published by this type of service.
| Parameters | |
|---|---|
| URL | URL of the service of an ArcGIS REST layer.e.g. http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Demographics/ESRI_Census_USA/MapServer/5 |
| Username | Enter the username to authenticate and log in to the ArcGIS REST service. |
| Password | Enter the password to authenticate and log in to the ArcGIS REST service. |
JMap Server
JMap Server can use a raster spatial data source that comes from another JMap Server instance. To enable this, you must start by configuring a connection towards the other JMap Server. Refer to JMap Server to JMap Server Connections for more information.
| Parameters | |
|---|---|
| Remote connection | Select the connection towards another JMap Server instance that must be used to extract spatial data and attributes. The connection must already be configured in JMap Admin. |
| Data source | Select the existing raster spatial data source on the other JMap Server instance you wish to access. The data source must be shared by the other server. |
OpenStreetMap
JMap Server can use the OpenStreetMap map as a raster data source. No parameters need to be configured for this type of data source.
WMS server
Web Map Service (WMS) is a standard proposed by the Open Geospatial Consortium that defines how client applications must request maps from a WMS compatible server. The protocol used is HTTP and the maps returned are typically images in popular formats (PNG, GIF, JPEG, etc.). WMS servers publish their capabilities in an XML document that specifies the types of requests supported as well as the metadata (list of layers, supported projections, etc.).
By configuring WMS data sources, you allow JMap to connect to and query WMS compatible servers (versions 1.0 to 1.3). You can then create raster layers based on these WMS data sources inside projects.
| Parameters | |
|---|---|
| Get server capabilities (GetCapabilities) | Enter the GetCapabilities URL that will return the WMS server’s capabilities. The URL should look like this: http://www.server.com/wms?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetCapabilities |
| Enable HTTP authentication | Enable this option if the WMS server controls access to the WMS service via HTTP authentication. In this case, enter the username and password that must be used. |
Once you have obtained the capabilities, you can define the parameters for the other types of requests in the WMS protocol. JMap Admin automatically suggests default queries that usually work very well. They are generated from the GetCapabilities request. If you wish to modify these default requests, you must select the Override default request option and enter new requests. For each type of request, you can also activate HTTP authentication and provide sign-on parameters.
| Parameters | |
|---|---|
| Get map(GetMap) | This request is used to get a WMS server map. |
| Get feature info(GetFeatureInfo) | This request is used to get the attributes of a map element. |
WMTS Server
Web Map Tile Service (WMTS) is a standard offered by the Open Geospatial Consortium that determines how client applications perform queries to obtain map data in the form of predefined tiles from a data server.
By configuring WMTS data sources, you enable JMap to connect to and query WMTS-compatible servers (version 1.0.0). You can then create raster layers based on WMTS data sources within projects.
| Parameters | |
|---|---|
| URL | Enter the GetCapabilities URL that will return the capabilities of the WMTS server. The URL should be similar to this one: http://www.server.com/wmts?SERVICE=WMTS&VERSION=1.0.0&REQUEST=GetCapabilities Examples: https://basemap.nationalmap.gov/arcgis/rest/services/USGSHydroCached/MapServer/WMTS/1.0.0/WMTSCapabilities.xml and http://cite.deegree.org/deegree-webservices-3.4-RC3/services/wmts100?service=WMTS&request=GetCapabilities Press Next to continue configuring the data source. |
| Original projection | Select the projection of the map data. |
| Start update automatically | Check this box to automatically update this data source. |