For BS5837 surveys, Arboricultural Consultants are often required to deal with CAD. OTISS supports you in various ways to get the job done quickly and easily.

  • Option 1: Starting with a CAD drawing as the site plan…
  • Option 2: Using a PDF site plan to produce CAD reports…
  • Option 3: Using OTISS with KeyTREE from Keysoft Solutions…
  • Option 4: Using OTISS with ArborCAD
  • Exporting survey data to CAD drawings for Tree Protection Plans…
Why do I need to use CAD?

You may ask “Why do I need to use CAD for the detailed Tree Protection Plans?”, let us explain why we have taken this approach.

  • Arboricultural consultants often work with architects who provide initial site/topo drawings in CAD format. OTISS users can load in these drawings and show them as a base-layer on which you can plot the trees. OTISS can then generate all the required spatial data for RPA, crown, shadow etc as a CAD/DXF file that can be sent back to the architects. The architects’ CAD users can then merge the survey data with the architectural drawings, and they have the CAD expertise to produce the required drawings.
  • CAD applications are designed to do this work; i.e. laying out drawings in minute detail, total control over all aspects of colour, line tightness, font, text placement, etc. And they have been developed and improved over decades.
  • Any tools that we could produce (or our competitors, or most drawing packages) will always fall short and compare ‘extremely’ badly with CAD applications.
  • But unfortunately, they don’t make CAD applications that are easy and intuitive. Its another skill to learn!
  • So it seems to be accepted practice to use survey tools to collect the data and then CAD for detailed modifications of the maps.

Option 1: Starting with a CAD drawing

Arboricultural Consultants are often provided with architectual CAD drawings as their site/topo plan. While surveying you can plot trees directly onto this base drawing. After surveying, OTISS can generate a DXF file containing the tree icons, RPA and shadow arcs (see below), which can be easily merged with the original CAD drawing.

Step 1: OTISS allows you to directly import CAD drawings. The drawing can then be used like any other uploaded map or site plan – you can pan/zoom around the map and plot trees onto the drawing. See Loading Maps & Plans for full details.

Step 2: Use the OTISS mobile survey apps and the CAD drawing to plot the trees and gather the BS5837 survey data. If the drawing has used the national grid co-ordinates, then you can also use GPS and also use the online maps and aerial images.

Step 3: The Reports-> CAD Data-> DXF format menu on the BS3837 spreadsheet page is used to generate a DXF file containing the tree icons, RPA and shadow arcs (see below). On the OTISS dialog panel: (a) Select the ‘Drawing unit’ for the DWG drawing that was loaded in step 1: metre or milli-metre. (b) Leave the Include image check box unticked – you don’t need the image because you have the original CAD drawing. The downloaded DXF file should be saved to disk. This file can now be merged with the original CAD drawing using your own CAD application (step 4), or can be sent directly to the architects and let them do it.

These next steps are intended to be used by people who have their own CAD application and are able to manipulate the drawing objects to produce the required set of Survey Plans and Tree Protection Plans to suit their requirements.

Step 4: To combine the trees and the site plan, you need to open the original drawing (using your CAD application) and use the appropriate command to ‘import’ or ‘merge’ the file that you have just saved (step 3). The co-ordinate system in both drawings should be the same, so if you are asked to provide or specify an ‘origin’ or ‘grid point’, then specify 0,0. Save this merged file under a new name.

Step 5: Use the CAD features to produce the printouts and Tree Protection Plans you require. For example:

Show/hide the survey layers as required.
Select a layer and change the colour and line styles. This will change all the items in that layer in one operation.
Select specific objects or select all the items in a single layer, then they can all be manipulated as required – e.g. change text font or size.
Customise and create offset RPAs as required for some of the trees.

Option 2: Using a PDF site plan to produce CAD reports…

Arboricultural Consultants often use PDFs or OS maps for their surveys, but they want to be able to produce CAD layouts and printouts for their BS5837 reports. After surveying, OTISS can generate a DXF file containing the tree icons, RPA and shadow arcs (see below), and this file can also include the image of the site plan. So, even though you did not start with a CAD site plan, you can use your CAD application to produce more sophisticated printouts.

Step 1: Load the PDF, map or site/topo plan as normal – see Loading Maps & Plans for details.

Step 2: Use the OTISS mobile survey apps to plot the trees and gather the BS5837 survey data. If the site plan can be geo-referenced to use the national grid co-ordinates, then you can also use GPS and also use the online maps and aerial images. See Loading Maps & Plans for more explanation about geo-referencing.

Step 3: The Reports-> CAD Data-> DXF format menu on the BS3837 spreadsheet page is used to generate a DXF file containing the tree icons, RPA and shadow arcs (see below). On the OTISS dialog panel, be sure to tick the Include image check box. When you press the Download button, you should expect to download both the DXF file and a TIF image file as well. The DXF file has all the tree data, and TIF file is an image of the original PDF (with no tree data). Place both the DXF file and the TIF file in the same folder on your computer. NB: The image file’s name must be as shown on the OTISS dialog – this name is stored in the DXF file – you may have to remove and “(x)” suffix that may have been added in the download process.

These next steps are intended to be used by people who have their own CAD application and are able to manipulate the drawing objects to produce the required set of Survey Plans and Tree Protection Plans to suit their requirements.

Step 4: Use you CAD application to open the DXF file. You will see a TIF image with the trees icons on top. The image is not stored inside the DXF file – it must be stored in a separate image file in the same folder. In AutoCAD (and most CAD applications), it seems to work best if you first load the DXF file, then Save it in the DWG format and close the file. This is because the OTISS generated DXF files contain the bare minimum of information, and may not be suitable as a ‘base’ file for complex drawings in all CAD products. When you open the DXF drawing in some CAD applications, you may have to use the ‘Extents’ or ‘Fit to window’ command to locate the trees.

Step 5: Use the CAD features to produce the printouts and Tree Protection Plans you require. For example:

Show/hide the survey layers as required.
Select a layer and change the colour and line styles. This will change all the items in that layer in one operation.
Select specific objects or select all the items in a single layer, then they can all be manipulated as required – e.g. change text font or size.
Customise and create offset RPAs as required for some of the trees.

Option 3: Using OTISS with KeyTREE

Many arboriculturalists and architects use the KeyTREE utility for plotting tree survey data onto AutoCAD drawings. OTISS is an excellant data collection system that can be used on-site to gather and collate the survey data. OTISS can then generate a KML formatted file that can be imported into KeyTREE. This makes it seamless to use OTISS for BS5837 data collection and KeyTREE for preparing your CAD drawings.

Step 1: OTISS allows you to directly import CAD drawings. The drawing can then be used like any other uploaded map or site plan – you can pan/zoom around the map and plot trees onto the drawing. See Loading Maps & Plans for full details. If the CAD drawings uses the national grid co-ordinates, then you can also use GPS and also overlay the drawing on the online maps and aerial images.

Step 2: Customise the BS5837 survey. All the standard BS5837 fields (category, height, canopy NESW, numStems, stemDiameters, lifeStage, lifeExpectancy, crownClearance, lowestBranch, etc.) should be used and will be exported to KeyTREE. In addition, setup the following fields.

OTISS Field
Name (KeyTREE)
customText1 Physiological Condition
customText2 Structural Condition

Step 3: Use the OTISS BS5837 Survey app to plot the trees and gather the BS5837 survey data. Sync the data to the OTISS website, and check the data using the OTISS maps and spreadsheet pages.

Step 4: Use the Reports-> CAD Data-> KeyTREE (kml) menu on the BS3837 spreadsheet page to generate a kml import file for KeyTREE.

Step 5: Startup AutoCAD with KeyTREE, open up the DWG drawing, and press the KeyTREE> KeyTREE Import button. Simply locate the OTISS generated KML file and import all the collected survey data. The trees will automatically be added to your drawing.

Notes:

  • KeyTREE does not support the import of polygon shapes for groups or hedges. OTISS provides all the information it can in the KML files about the trees, groups and hedges – but importing the actual polygon shapes is not supported by KeyTREE. If you import the polygon data separately, you can use the Add Tree/Hedge Group function to assign the data.
  • OTISS does not collect information about (a) root spread or (b) 8-point canopies. If required, this information would have to be collected separately and inputted to KeyTREE after Step 5 above.

Option 4: Using OTISS with ArborCAD

We know that many arboriculturalists have bought and use the ArborCAD utility for plotting tree survey data onto AutoCAD drawings. OTISS provides a Report option to download an Excel spreadsheet that is compatible with the ArborCAD system. This makes it seamless to use OTISS for BS5837 data collection and ArborCad for preparing your CAD drawings.

Step 1: OTISS allows you to directly import CAD drawings. The drawing can then be used like any other uploaded map or site plan – you can pan/zoom around the map and plot trees onto the drawing. See Loading Maps & Plans for full details.

Step 2: Use the OTISS BS5837 Survey app to plot the trees and gather the BS5837 survey data. If the site plan can be geo-referenced to use the national grid co-ordinates, then you can also use GPS and also use the online maps and aerial images. See Loading Maps & Plans for more explanation about geo-referencing.

Step 3: Use the Reports-> CAD Data-> ArborCAD Excel menu on the BS3837 spreadsheet page to generate an Excel spreadsheet for ArborCAD.

Step 4: Next you will need to setup an ArborCAD Filter. Full details are provided in the ArborCAD Help File Creating an ArborCAD filter from Excel on the ArborCAD website. You only have to setup the filter once. Save this filter for use on all the OTISS surveys.

Step 5: To import the OTISS data into ArborCAD, simply open the OTISS data spreadsheet using Excel and copy all the data to the clipboard. Then use the ArborCAD File-> “Import and Convert Survey Data from Clipboard” menu option to import the data. Its all explained in the above Help File!

 

Exporting survey data to CAD for Tree Protection Plans…

In OTISS we show the standard RPA and average crown radius on our maps. But we also generate a CAD/DXF file, that you import it into your CAD application. In CAD you can see the asymmetric crown radius; carry out detailed changes to the RPA; and add extra details for protective fences and ground cover.

On the BS5837 spreadsheet page, use the Reports menu to generate the CAD/DXF file. Using your own CAD application you can combine this file with your existing CAD drawings plans. The DXF file contains:

  • The RPA is provided both as a shaded circle (grey) and as an adjustable 12 sided polygon (yellow). For tree groups and hedges, the polygon is drawn.
  • Each aspect of the tree is plotted on a separate DXF layer so that you can instantly customise the colours, linewidth and visibility for all the trees by changing the layer’s properties with your CAD application.
  • The DXF file contains only the tree information, it does not contain a background map.
  • Each tree is plotted using simple XY co-ordinates (metres) for site plans, or the Grid Reference coordinates for maps. For example, an item at location ‘TL 05635 04970’ will be plotted at x=505635 y=204970.
  • The trees selected for the inclusion in the DXF is governed by the Site and Survey filters at the top of the BS5837 web page. At present the column filtering is ignored when compiling these reports.

 

 

DXF Layers in the BS5837 drawings

DXF Layer Description
Site Plan Layer This layer contains the image of the site plan or map that was loaded into OTISS. The image is not stored inside the DXF file – it is stored in a separate image file in the same folder.
Tree_Locations Layer This layer contains the small circles that represent the tree trunk. The colour corresponds to the BS5837 retention category. The line thickness and visibility for all the trees can be changed using the layer’s properties.
Tree_CrownSpread Layer This layer contains a distorted circle to represent crown spread using the N, S, E, W measurements. The colour corresponds to the BS5837 retention category. For tree groups and hedges, the polygon is drawn. The line thickness and visibility for all the trees can be changed using the layer’s properties.
Tree_Reference Layer This layer contains each tree’s reference number and is plotted beside the tree using the TreeText text style. The colour corresponds to the BS5837 retention category. The text font and height can be changed using the text style’s properties. The text can be removed by hiding the layer.
Tree_Reference2 Layer This layer contains each tree’s reference number and the BS5837 retention category, which is plotted beside the tree using the TreeText text style. The colour corresponds to the BS5837 retention category. The text font and height can be changed using the text style’s properties. The text can be removed by hiding the layer.
Tree_Species Layer This layer contains each tree’s species name, which is plotted beside the tree using the TreeText text style. The colour corresponds to the BS5837 retention category. The text font and height can be changed using the text style’s properties. The text can be removed by hiding the layer.
Tree_RPA Layer
This layer contains a shaded circle representing the calculated RPA. For tree groups and hedges, the polygon is drawn. The colour and visibility for all the trees can be changed using the layer’s properties.
Tree_RPA2 Layer
This layer contains a 12 sided polygon representing the calculated RPA. For tree groups and hedges, the polygon is drawn. Your can adjust the polygon to show the desired root protection fencing. The line colour, thickness and visibility for all the trees can be changed using the layer’s properties.
Tree_Shadow Layer This lay contains a shaded arc representing the typcial shadow pattern – it is an arc from NW to E using the tree height as radius. For tree groups and hedges, the polygon is drawn. The colour and visibility for all the trees can be changed using the layer’s properties.
TreeText Style This text style is used for both the Reference and Species text. The text font and height can be changed using this text style’s properties. In some CAD applications, you may need to re-apply the text style to the text items to make the change – please consult your application’s reference manuals.

 

Some Background – CAD file formats

There are a number of CAD file formats, but the DXF format is the one we use within OTISS. The following definitions are from Wikipedia.

AutoCAD DXF (Drawing Interchange Format, or Drawing Exchange Format) is a CAD data file format developed by Autodesk[1] for enabling data interoperability between AutoCAD and other programs. [omitted]. Autodesk now publishes the DXF specifications on its website for versions of DXF dating from AutoCAD Release 13 to AutoCAD 2010.

DWG (“drawing”) is a binary file format used for storing two and three dimensional design data and metadata. It is the native format for several CAD packages including AutoCAD, IntelliCAD (and its variants) and Caddie. In addition, DWG is supported non-natively by many other CAD applications. The .bak (drawing backup), .dws (drawing standards), .dwt (drawing template) and .sv$ (temporary automatic save) files are also DWG files.

What this means in practice is that; (a) the DWG format is owned by AutoDesk, it can only be used under license, and is not compatible with all CAD products, whereas most products use DXF to exchange CAD drawings between different CAD products (including AutoCAD) – so we generate DXF files for the surveyed trees.

DWG TrueView is a free (and very powerful) CAD ‘viewer’ application provided by AutoDesk (the makers of AutoCAD). It allows you to read the OTISS DXF file, to change the colours and lineweights of the layers, and to generate plots.