Data Capture, Cleansing and Verification
We use MapInfo, ESRI ArcGIS and open-source GIS (QGIS, GRASS) to deliver data capture and cleansing services that are efficient and deliver high quality outputs.
Data Capture
We capture data from a variety of sources: hardcopy or scanned maps, aerial photographs, existing spatial and/or non-spatial data. We assess the source data to determine the most efficient method of capturing the data and agree the required accuracy and scale with the client to ensure the digitised data meets the client's specification. Bespoke data capture tools may be used to ensure that attribute data is captured efficiently to a consistently high standard.
Exegesis also provide survey services.
Data Cleansing and Verification
Exegesis offers a data cleansing and verification service to assist in resolving the following issues:
- Datasets captured at different scales
- Datasets captured in different projections
- Spatial inaccuracies e.g. overlaps, gaps
- Attribute errors e.g. missing values, misspelt or superseded terms
We review existing data, required output format and quality criteria to determine the best approach to cleanse the existing data. This may include:
- Re-projecting all source layers to a single projection
- Checking the spatial data for geometry issues
- Modifying the data to improving the spatial accuracy using up-to-date base mapping data
- Checking the attribute details and flagging records which are incorrect