Geographical Information Systems (GIS)

Map Mashups, Desktop Studies, Software Development

 

We are pleased to offer GIS maps based on licensed Ordnance Survey (OS) map extracts with other detail overlaid.

This can include ground levels sourced from National Open Data LIDAR archives from which we can generate a contour model and representative grid of spot levels. This is the next logical progression from our value-management Levels survey provision. All data is initially sourced from national archives without the overhead of us physically surveying the site.

Other detail which can be included are, for instance, Planning Authority maps such as conservation areas and TPOs, DEFRA ancient woodland & habitats, Land Registry general boundaries and design drawings.

We can also integrate our survey detail - perhaps only the key part of a site or a particular feature type (trees).

In addition to our long-standing Land Surveying tradition we also have extensive experience in software engineering. We develop GIS software  including an extensive set of AutoLisp functions, a Topographical Survey processing suite and miscellaneous utilities such as for OpenData LIDAR data processing.

GIS Mashups

 

Mashups

We are pleased to offer GIS maps, for instance based on licensed Ordnance Survey (OS) map extracts with a mix of detail overlaid from other sources.

LIDAR Levels

Mashups can include ground levels sourced from National Open Data LIDAR archives from which we can generate a contour model and representative grid of spot levels. This is the next logical progression from our value-management Levels survey provision. All data is initially sourced from national archives without the overhead of us physically surveying the site.

LIDAR (Light Detection And Ranging) data is available in different resolutions across the country. This has been acquired by the Environment Agency using aerial reconnaissance. Some areas are restricted to 2metre, 5m or 10m resolution, though in many areas there is coverage of 1m resolution. This provides a grid of levels representing the prevailing ground height over each grid square.


There are two types of dataset, DSM - Digital Surface Model and DTM - Digital Terrain Model. The latter is generally derived from the former by removing buildings and other above-ground features from the DSM model. These spot heights are to Newlyn datum and are reportedly accurate in height to between +/-5cm and +/-15cm.

Terrain Models

Using our in-house GIS software utilities, we can use this raw, raster data to generate terrain models (DTM, DSM or both in separate layers), contour models and grids of spot levels (say at 5, 10 or 20m intervals).

Furthermore we can integrate spot levels from different data sets, for instance our own measurements or spot levels from a third party survey.

Preliminary Assessment

These desktop plans are potentially suitable for use in design/costing of Architecture, landscaping(cut/fill analysis) or drainage proposals, or for line-of-sight analysis, Planning impact assessment or Flood Risk assessment.

Sources

The plan could form the framework for your design/study model with other existing and design detail directly overlaid as required. We have experience and capability integrating different map data. We routinely overlay and combine other data such as Defra habitat maps, Local Plan spatial models, Title Plans and 3rd party design plans such as proposed highway improvements. These can be incorporated to enhance the CAD model as and when required as your project progresses.

Survey Integration

Our detailed topographical surveys are oriented to OS grid and Newlyn datum (ODN). So, we can accurately survey key specific areas and directly overlay them to the plan, for instance the immediate area around a proposed localised development. We can survey specific categories of detail perhaps missing from the desktop study, for instance to plot individual tree positions ready to support an Arborology Survey. Equally we could install and record a network of GNSS or TPS survey ground controls to orientate future surveys and setting out.

Value

This approach offers value for money, a relatively low upfront cost and potentially reduced lead times for design or preliminary assessment activities. There are OS Map licensing costs and our fees for processing and presentation, but this may be a fraction of the cost of a full land survey undertaking whilst giving you the flexibility to extend to a full survey, if and when required.

Software

 

Built on Technology

In addition to our long-standing Land Surveying tradition we also have extensive experience in software engineering.

We develop software in-house as part of our drive for continuous improvement, where opportunity exists to:

  • improve our accuracy or efficiency, for instance with automation of repetitive or complex processing tasks;

  • avoid altering our tried and tested survey methodology to fit off-the-shelf software;

  • provide a more cost effective and sustainable solution than buying bulky software packages with surplus functionality; and

  • to aid quality control by reducing risk of manual errors or procedural variation and by providing an audit trail of data.

Software Products

Our in-house surveying software utilities can be supplied under licence.

We would be pleased to discuss your requirements for development of solutions specific to your needs.


Aside from this web site, which was prepared in-house, here are some examples of what we produce.

Survey Processor

This effective Excel/VBA spreadsheet solution has been developed using our combined expertise in Land Surveying and software engineering for our own Land Surveying purposes. It provides:

  • survey data enrichment forms,

  • closed traverse assessment and correction,

  • cartesian translation,

  • local survey orientation and translation to GNSS control co-ordinates and

  • output of DXF point data for drafting.


It includes a configurable point coding system, feature scaling and scale assessment of appropriate print sheet size.


It also automatically drafts simple detail information such as annotation, control stations, trees, rectangular & circular detail features, and generates a 3D point cloud and control station & tree schedules.


Transformation routines also allow for orientation into sectional planes, useful in drafting of simple building elevations from Total Station point data without the capital expense of laser scanning.


We would be pleased to discuss licencing terms or to develop similar solutions to your specific requirements.

AutoLisp Functions

We develop AutoLisp routines for our own use in Survey processing & drafting and arising from our Geospatial Software R&D.


We can develop functions specific to your needs. Some examples of functions which are already available to buy under licence, are:

Miscellaneous Terrain Modelling

TIN - This routine creates a Triangulated Irregular Network from a selection of 3D points. This is useful for terrain modelling.

TSwap - This routine swaps round two adjacent TIN triangles.

Contour - Generates contour lines at given minor and major intervals, from a selected TIN.

ContourLabel - Labels the height of contour lines where they intersect with a selected polyline.

Make Spot - Creates spot heights at a given grid interval (say 10m) across selected denser grid of 3D points (say 1m lidar levels).

Make Point - Creates a 3D point at a selected 2D co-ordinate with the reduced level taken from a selected spot height text.

Interpolate - Creates a series of 3D points and spot heights at a given horizonal or vertical interval between two selected 3D points.

Inter Offset - Creates a 3D point & spot height at a given distance along a notional line extended from two selected 3D points.

DatumShift - The numerical values in all selected level spot height text are adjusted by the given offset value.

Points - This outputs the co-ordinates of all segment endpoints in a polyline (for instance which represents the waypoints in a route). This is useful for RTK GNSS route planning as the output can be saved as a csv file then uploaded as a stakeout file to RTK GNSS or EDM equipment, e.g. to survey a grid of spot levels.

ListPoints - Outputs a comma-separated list of the x,y,z values of all selected 3D points. Useful for preparation of a csv file to accompany a CAD drawing.


Drafting

Above - Creates a 3D point & spot height at a given vertical distance above another selected 3D point. Useful for annotating reduced levels for cill/beam/ceiling levels from notes given in terms of relative height above floor level.

Bank - Draws a bank comma between two selected points.

Door - Draws an outline door for use in floorplan drafting.

Gate - Draws a cross symbol to represent a gate between two selected points.

Hedge - Draws a jagged hedge outline in place of a given polyline for representing hedges and vegetation.

Height - Creates an arrow indicator and height label for a selected point. Useful for labelling elevations.

LatLong - Draws and labels a map grid to a given rectangular border.

MoveRect - Minor utility routine for drafting productivity to move the centre of a selected rectangle to a given point.

Spot - Creates a spot height (3dpoint, cross and height label) by selecting a point in a point cloud.

Window - Draws an outline window for use in floorplan drafting.

LIDAR Integation

GIS Expertise - We have considerable in-house expertise with Geospatial Information Systems software and we have recently put this to good use in preparing an efficient customised workflow and software utilities to import, integrate and present government LIDAR Open Data in CAD (DWG AutoCAD format).

 

Conversion - We have developed a simple utility program, asc2dxf, to sweep a set of OpenData LIDAR tiles (*.ASC format) and extract the heights as spot heights for a given geographical extent, outputing to a single dxf file of 3D points. Grid interval can be varied, for instance sampling at 10m intervals over 1m resolution source data.

 

Terrain Models - From the 3D points we can generate terrain models (i.e. triangulated irregular network or contour models) be it DSM-based, DTM-based or with both overlaid in separate layers to the electronic CAD model.

 

Spot Heights - We have an in-house software facility to generate a grid of annotated spot heights at a chosen grid interval, say 5, 10 or 20m grid across the LIDAR dataset.

 

Mashup Surveys - See our GIS Mashups provision for more information on integrating this with Ordnance Survey maps, our land surveys and more. The detail is presented to useful sheet sizes (A4-A0) and standard annotation scales (1:50-1:2,500).

Utility Spreadsheets

We develop and employ utility spreadsheets to assist with productivity and quality control. These are not currently for sale, but please contact us to discuss provision of utility spreadsheets to meet your requirements. Some examples are:


Level Traversal Spreadsheet

This set of spreadsheets provides for entry, review and reporting of levels traversals, e.g. for repeated building monitoring.


Installed to a laptop computer, we can immediately review the traversal on site, with closure and multi-sighting variations.


The reduced levels of the points are then automatically tabulated for transfer on to the weekly sheet. Threshold divergencies or anomalies can then be identified for immediate checking or reporting as applicable.


Map Tile Query

Provides OS map tile name and extent for OS Streetview and for OpenData LIDAR, given an OS grid co-ordinate. Useful to identifying which tile is required for selecting and geo-positioning this 3rd party data.


Soak-Away Calculator

Estimates soak-away pit size requirement for a given area and assumed SIR and rainfall ratio, to BRE365 using Z1/Z2 rainfall tables. This can be useful for documented evidence of due process, if required in building control applications.


Tree Height Calculator

Calculates tree height using vertical angle to the crown where wind sway prevents measurement of vertical distance with EDM.

General Software Development

We have expertise in software development in a number of sectors including GIS, Finance, Telecomms, Military Simulators and Animation and covering many programming languages including C, C++, Java, Python, Lisp, VB and SQL.

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01903 267883

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