The main thing to remember, with regard to any desktop GIS system, is that if you get the basic set up correct in the first place, you will save a lot of hassle later on. By this, I mean you need to sit down and evaluate what you want to achieve from use of the GIS before attempting to create your project.
As the three major systems, ArcGIS, MapInfo and QGIS, place certain constraints on how you input, display and print data it is important to understand what is feasible and what is not. Remember that you are usually creating a series of layers on top of the base map which contains the foundational information of the project.
As the three major systems, ArcGIS, MapInfo and QGIS, place certain constraints on how you input, display and print data it is important to understand what is feasible and what is not. Remember that you are usually creating a series of layers on top of the base map which contains the foundational information of the project.
Each layer will contain information in a vector or raster format. This involves point, line or polygon geometry for the vector layers and dot data for raster layers. These layers will represent the various types of information you are working with. For example, if you have a vector layer, which consists of point data, that represents various types of trees, you may decide that you only want to know what type of tree it is at this stage. For instance, you only need a record denoting that it is an oak, ash or pine tree. However, you may also collect other data about the trees at a later stage such as their age, condition and value. There could also be many other features of the trees which you could also collect data on. So you will have to decide what fields in the attribute database, associated with the layer, need creating in the first instance. Remember you can also add more fields later as necessary. Each record contains one or more fields and you will need at least one field, which represents a unique identifier, of the item being monitored. If each tree in the project has been marked with an identifier - either numeric or alpha/numeric you then have a means of searching specifically for a specific unique tree. So it is important to create a unique identifier, for each item being monitored, if you need to identify objects within a layer other than it is say an ash, oak or pine tree. For , you could use something like 10hT/Ash/0001 to denote the first ash tree in section 10hT. This particular identifier contains both text and numbers so will have to be created as a text field. This identifier also assumes that no more than 9,999 of type ash would occur in this section. If you knew there was a possibility of 10,000+ trees then you would need to adjust the identifier accordingly. Otherwise you would run out of unique identifiers. That is why whatever system of identification you use it must be robust enough for your specific requirements now and in the future. Also, depending on the complexity of your requirements, will decide whether you choose to connect a flat or relational database to your project information.
If you would like to know more about desktop GIS and how it could help your organisation jps services offer training courses in ArcGIS, MapInfo and Quantum GIS. These courses, either at your site or a location nearby, can be tailored to your individual requirements. Please use the contact form if you would like more information.
If you would like to know more about desktop GIS and how it could help your organisation jps services offer training courses in ArcGIS, MapInfo and Quantum GIS. These courses, either at your site or a location nearby, can be tailored to your individual requirements. Please use the contact form if you would like more information.
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