NagVis Geomap

Introduction

The NagVis Geomap map source was introduced in NagVis 1.7. It has been developed to get well rendered and scaled overview maps without much work.

The geomap renders several hosts on an Open Street Map powered map which is used as background image.

For the current geomap all you need is a CSV file which tells NagVis the hosts to render and the geo coordinates where the hosts should be positioned at.

Prerequisites

There is no special software needed on the NagVis host. But there is one special requirement. To be able to use this feature, NagVis needs to be able to access the host geomap.nagvis.org via port 80. NagVis uses a simple HTTP based API to get the map image and the coordinates of that image.

In most cases the NagVis host does not have direct internet access. You can configure the http_proxy option in the [global] section of your NagVis main configuration to tell NagVis to use a proxy such requests.

The first call

NagVis comes with a demo geomap called "demo-geomap". If your NagVis is configured correctly you should see a map of germany with two nodes. One node is showing the host "ham-srv1" in Hamburg. The other host "muc-srv1" is located in Munich.

The geomap is defined using the regular map configuration file "demo-geomap.cfg". The contents look like this:

global {
    sources=geomap
    alias=Demo: 4 Geomap
    parent_map=demo-overview
    iconset=std_medium
    backend_id=demo
    # Geomap Parameters
    source_file=demo-locations
    width=800
    height=600
}

The sources=geomap line tells the map to use the geomap source for altering the map configuration. The source_file=demo-locations definition tells the geomap source to use the file demo-locations.csv located in the etc/geomap directory.

The demo-locations.csv file contains the following two lines:

ham-srv1;Hamburg Server 1;53.556866;9.994622
muc-srv1;Munich Server1;48.1448353;11.5580067

Each line defines one host to be added to the map. The columns are separated by ; signs. The first column contains the host-name, the second an optional alias, the third the LAT coordinate and the fourth the LONG coordinate.

Configuring geomaps

The geomap source uses view parameters for configuration. For details take a look at the modify view dialog which can be opened using the header menu "Actions -> Modify view".

The view parameters can also be given as map configuration attributes in the global section of the maps.

ParameterDefaultDescription
geomap_type mapnik Define the render mode of the geomap. Can be osmarender, mapnik and cycle.
geomap_zoom Configure the zoom level of the geomap during map request. Take a look at the OSM zoom documentation for further details.
geomap_border 0.25 The border to add on each side of the geomap. This value is simply added to the calculated min/max geo coordinates.
source_file The name of the CSV file to use as source for rendering the geomap.
width Defines the width of the geomap in pixels. The maximum size of the geomap is limited by the queried webservice. geomap.nagvis.org supports up to 50 tiles per map which should make 1920x1080 resolutions possible. Please contact us if you need more.
height Defines the height of the geomap in pixels. The maximum size of the geomap is limited by the queried webservice. geomap.nagvis.org supports up to 50 tiles per map which should make 1920x1080 resolutions possible. Please contact us if you need more.