Exegesis Spatial Data Management


Posts in Category: GIS (general)

Opening ESRI Personal Geodatabases in QGIS

In the more recent 64-bit versions of QGIS it is no longer possible to open ESRI personal geodatabases using the 'Add vector layer' functionality. However, it is possible to enable access to personal ... read more

How to hide the MapServer map file location on IIS (without writing any code)

We posted some notes a few days ago on how to set up MapServer WMS/WFS server on IIS. Someone called Dennis has commented appreciatively, but asked how to hide the location of the .map file and... read more

Calling a secured WMS / WFS service from mapserver

Mapserver can be used in a cascading manner to call to other services, potentially combining them and maybe re-projecting before serving out again. Reasons for this might... read more

Using R with spatial data

R is a cross platform statistical package which is becoming extremely widely used. It is modular and so there are all sorts of add ins available, including a number of sophisticated tools for... read more

How to set up a MapInfo DBMS table from SQL Server without a DSN

A quick note to say that it is definitely possible to use a SQL Server spatial table in MapInfo Professional without an ODBC DSN. There's not much about this on the web, and the normal methods of... read more

Optimising SQL Server spatial indexing - let sql do the work..

Note – this will take a LONG time to run – quite possibly many hours - on a big dataset as it drops and recreates the index using different parameters – sledgehammer approach, but given the... read more

When GeoServer forgets about GeoWebCache

I’ve been setting up some new mapping services (WMS) in GeoServer, with GeoWebCache allowing the map tiles to be cached for performance. For this to work, and for the WMS to use its cache of tiles,... read more

British National Grid in MapInfo

A problem frequently encountered with sharing data between MapInfo and ArcGIS is that the British National Grid projection used by ArcGIS is accurate to 1 mm, whilst the standard projection used... read more

Calculating the extent of the geometry in a SQL Server table

Andy Brewer passed me this, adapted from http://barendgehrels.blogspot.co.uk/2011/04/extent-of-sql-server-spatial-table.html This is a useful script, using CTEs (common table expressions) to... read more

MapServer and GeoServer (and tilecache) comparison serving Ordnance Survey raster maps

With two WMS running off identical data on the same server, I thought it would be interesting to compare speeds and the map output. So I lined up a map request with identical parameters to both... read more
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