MapInfo polygon order

Hi there - a few things to note then. First, a MapInfo Table is reasonably dumb when it comes to draw-order, in that it cannot maintain a draw order. As a result, if you open a MapInfo table in MI Pro with multiple polygons drawn overlapping each other, today some buildings will be on top of fields, tomorrow when you open the same file those self same features will have changed their order with different features now obscured. The only real solution is to split certain OS Feat_Codes out so that they go to a different target MapInfo TAB file, that way you are in control with MapInfo's Layer Control...

 

 

Secondly, specifically the OS MasterMap TopographicArea featuretype, is 1 feature thick throughout. That means with just that layer shown, if you were to stick a hypothetical pin into the map, you would only ever hit 1 feature... There are also no holes in TopoArea...It's like a very large blanket covering Great Britain. That said I suspect what you have done is merge features that reside on the CartographicArea feature type into the same layer as TopographicArea... thats not ideal as typically you would want Carto features like 'Slope' on the top of your Topographic features, such as a verge feature or a slip road for a grade separated motorway. I'd recommend that all your Carto features are added to a separate layer to your Topo feaures. 

 

 

A resource that I have no doubt you'll find as useful as I do is here. Good luck.

 

 

http://www.ordnancesurvey.co.uk/oswebsite/products/os-mastermap/topography-layer/feature-catalogue/OS%20MasterMap%20Topography%20Layer%20Feature%20Catalogue.htm

Hi 1SpatialDave,

 

 

Thanks for the info, agree with your assessment of the MapInfo. Tab.

 

I have already grouped the various OS feature codes into more usable .tabs that are layered in an appropriate manner.

 

 

But, I was thinking of creating a more generalised .tab for basic users of GIS and if FME could provide a 'magic bullet' for me to achieve this without the use of seamless .tabs.  I think from what you have suggested the answer is no.

 

Thanks anyway.

 

 

MSMGIS

With OS MasterMap because of the volume its hard to avoid Seamless Tables as MapInfo Tab has a 2GB file size limit so you quickly hit it unless you strip out lots of attributes... even then the bulk of the size is the geometry.

 

 

One option you might consider though is Rasterizing MasterMap if you need a silver bullet, raster might be it. Assuming you order your features prior to them entering the Rasterizer you'll be able to layer them correctly. Depending on the level of coverage you have you might get some quite big geographies into quite large images that means a user can just turn on BasingstokeSouth.Tab and have a large scale view of the area. Either that or create raster tiles and revert to seamless tables, which in this case means you only have a set of tiles to call rather than the user having to worry about different layers.

davideagle wrote:

Hi there - a few things to note then. First, a MapInfo Table is reasonably dumb when it comes to draw-order, in that it cannot maintain a draw order. As a result, if you open a MapInfo table in MI Pro with multiple polygons drawn overlapping each other, today some buildings will be on top of fields, tomorrow when you open the same file those self same features will have changed their order with different features now obscured. The only real solution is to split certain OS Feat_Codes out so that they go to a different target MapInfo TAB file, that way you are in control with MapInfo's Layer Control...

 

 

Secondly, specifically the OS MasterMap TopographicArea featuretype, is 1 feature thick throughout. That means with just that layer shown, if you were to stick a hypothetical pin into the map, you would only ever hit 1 feature... There are also no holes in TopoArea...It's like a very large blanket covering Great Britain. That said I suspect what you have done is merge features that reside on the CartographicArea feature type into the same layer as TopographicArea... thats not ideal as typically you would want Carto features like 'Slope' on the top of your Topographic features, such as a verge feature or a slip road for a grade separated motorway. I'd recommend that all your Carto features are added to a separate layer to your Topo feaures. 

 

 

A resource that I have no doubt you'll find as useful as I do is here. Good luck.

 

 

http://www.ordnancesurvey.co.uk/oswebsite/products/os-mastermap/topography-layer/feature-catalogue/OS%20MasterMap%20Topography%20Layer%20Feature%20Catalogue.htm

With OS MasterMap because of the volume its hard to avoid Seamless Tables as MapInfo Tab has a 2GB file size limit so you quickly hit it unless you strip out lots of attributes... even then the bulk of the size is the geometry.

 

 

One option you might consider though is Rasterizing MasterMap if you need a silver bullet, raster might be it. Assuming you order your features prior to them entering the Rasterizer you'll be able to layer them correctly. Depending on the level of coverage you have you might get some quite big geographies into quite large images that means a user can just turn on BasingstokeSouth.Tab and have a large scale view of the area. Either that or create raster tiles and revert to seamless tables, which in this case means you only have a set of tiles to call rather than the user having to worry about different layers.

Hi - Interesting angle, I shall give it a go.

 

 

Thanks

 

 

MSMGIS