Using the Open Remote Dataset Dialog

You can connect to a remote dataset using the Open Remote Dataset dialog when you are already familiar with the connection details of the dataset. This option offers a more direct way of connecting to remote datasets, compared to the Remote Connection Manager, which lets you browse and explore remote datasets.

Follow these general steps:

1. Select File > Open Remote Dataset from the ENVI menu bar. The Open Remote Dataset dialog appears.
2. There are two ways to open a dataset from this dialog:
• To open a new dataset, type (or paste) the connection string for the dataset in the URL field. See the sections below for guidelines on connecting to specific dataset types.
• If you have previously opened datasets, click the arrow and select the dataset from the drop-down list.
3. If the server requires login authorization, enter the Username and Password. Otherwise, leave those fields blank.
4. Click OK.
5. Depending on your display preferences, the dataset may automatically display in the Image window and appear in the Layer Manager. If it does not automatically display, you can drag-and-drop remote dataset layers from the Layer Manager to the Image window or to multiple views.

For more specific guidelines, see the following sections:

• Connect to OGC Servers
• Connect to Cloud Optimized GeoTIFF Files
• Connect to ArcGIS Image Services
• Connect to JPIP Servers
• Connect to Jagwire Servers

Connect to OGC Servers

Enter a connection string that consists of the server name, port number, CGI get request (followed by a question mark), and optional OGC keywords. Preface the URL with http:// or https://. The following is a sample connection string for a Web Mapping Service (WMS) dataset:

http://ogc-server.org/cgi-bin/mapserv_dem?SERVICE=WMS&coverage=strmplus_raw&width=1000&height=1000&bbox=-105,39,-104,40

Because no port number was specified in the example above, ENVI uses port 80 as the default.

You can also define a proxy server by setting the OGC Proxy Server preference.

OGC Connection Keywords

Standard OGC parameters specify details about what data to open on the server and how to open it. Here are some general tips for using keywords in connection strings:

• Specify keywords and values using an equal sign (=), and separate keyword/value pairs with an ampersand (&); for example: width=500&height=500.

• For WFS, set the service keyword to WFS.

• For WMTS, set the service keyword to WTMS.

• For WCS, ENVI loads the data using the highest WCS version that the server supports. You can set the version parameter value as needed for best results. See the Remote Data Sources Background topic for the WCS versions that ENVI currently supports.

The following table lists keywords that are only used with certain OGC data types. It is not an exhaustive list of all available OGC keywords.

Keyword	Description
WCS and WMS keywords
format	The file format in which to transmit the data across the Internet. The format must be among the list of formats supported by the OGC server. The server publishes the image formats it supports, and ENVI displays a subset of image formats from the list that it supports, namely JPEG, PNG, GIF, and TIFF/GeoTIFF. If the server does not support the specified format, it is not displayed. Example for WMS and WMTS: format=image/jpeg Example for WCS: format=geotiff
WCS-only keywords
coverage	Required. The name of the dataset. Example: coverage=srtmplus_raw
crs	The coordinate reference system of the image. This keyword value must be a string that comes from the list of reference systems supported by the server. Example: crs=EPSG:4326
version	The WCS version. Example: version=1.0.0
WFS-only keywords
typenames	Required, WFS versions 2.0 and later. The name of the feature type. Example: typenames=namespace:featureType
typename	Required, WFS version 1.1 only. Same as above.
count	Optional, WFS versions 2.0 and later. The maximum number of features to download. Example: count=200
maxFeatures	Optional, WFS version 1.1 only. Same as count.
startIndex	Optional, WFS versions 2.0 and later. The index of the first feature to download. Example: startIndex=5
bbox	Optional. The bounding box coordinates in order a1, b1, a2, b2. The order is determined by the coordinate system of the feature dataset. To use a different coordinate system to define bounding box coordinates, specify the coordinate system in the string, e.g., a1, b1, a2, b2, CRS.
WMS-only keywords
height	The number of rows in the image when it is opened. The default for WCS is to use metadata from the image. Example: height=500
layers	Required. The name of the layer. You can specify multiple, comma-delimited layers. ENVI will allow the server to combine the WMS layers and display them as a single layer. Example: layers=streets
srs	The spatial reference system of the image. This value must be a string that comes from the list of reference systems supported by the server. Example: srs=EPSG:4326
style	The display style from the server-supported style list. This specifies how to display certain features, if used (for example, display a two-pixel yellow line for roads). Example: style=visual
width	The number of columns in the image when it is opened. The default for WCS is to use metadata from the image. Example: width=500

Connect to Cloud Optimized GeoTIFF Files

Enter a connection string to an HTTP server or Amazon Web Services (AWS) S3 bucket as follows:

http://domain.com/path/filename.tif

Or:

s3://path/filename.tif

Examples:

http://landsat-pds.s3.amazonaws.com/L8/003/017/LC80030172015001LGN00/LC80030172015001LGN00_B1.TIF

 

s3://sentinel-cogs/sentinel-s2-l2a-cogs/1/C/DK/2018/12/S2B_1CDK_20181226_0_L2A/B02.tif

You can also access Cloud Optimized GeoTIFF files in the ENVI API, using ENVI::OpenRaster. See Cloud Optimized GeoTIFF Files on S3 Buckets for an example.

S3 Credentials

If you are accessing an S3 bucket that requires login credentials, you can provide credentials using any of the methods outlined below. If you use ENVI to access Cloud Optimized GeoTIFF files on an EC2 instance, ENVI will automatically use your EC2 credentials.

Environment Variables

You can set the following environment variables. Follow the links to the respective AWS documents, for instructions on setting them:

• AWS_SECRET_ACCESS_KEY: Use this to configure the AWS secret key.

• AWS_ACCESS_KEY_ID: Use this to configure the AWS access key.

Shared Credentials File

You can store credentials in a text file in one of the locations described in the AWS documentation, depending on your operating system. This is the best place to store sensitive information such as secret keys. Use the AWS_SHARED_CREDENTIALS_FILE environment variable to set the location of the credential file.

The contents of a credentials file look like this:

[default]

aws_access_key_id = MyAccessKeyID

aws_secret_access_key = MySecretKey

Connect to ArcGIS Image Services

Enter a URL that follows a Simple Object Access Protocol (SOAP) or Representational State Transfer (REST) convention.

The following example shows a URI for accessing a raster catalog. These raster types always stream in TIFF format so that you are getting actual source data.

http://server:port/arcgis/rest/services/folder_name/dataset_name/ImageServer/catalog_ID

Connect to JPIP Servers

Enter a connection string as follows:

jpip://server:port/file.jp2

Other supported file extensions include .j2c and .jpx.

Connect to Jagwire Servers

Enter a connection string that consists of the Representational State Transfer (REST) URL path, IP address or server (host) name, port number, the asset name, and dataset name. Preface the URL with https://. For example:

https://myserver/geoserver/ows?service=WCS&coverage=dataset_name

See Also

Remote Connection Manager, Remote Data Sources Background, ENVI::OpenRaster