Long-Term Planning for Vegetation Management

Mapping

Contents

Learning Objectives

[6a] describe the mapping information, capabilities and resources needed to complete a long-term management plan;

Narrative

Maps are used in the long-term plan to present the results of data collection, to plan management actions and to evaluate effectiveness. Without a map, it is easy to get lost in a long-term plan!
The requirements for mapping are
  1. sources for data to be mapped
  2. means to combine the data into a single map.
For small operations, a low-tech mapping system may be sufficient. Paper maps, or digital images of maps that can be printed out on paper, form the foundation of the traditional mapping system. Topographic maps may be ordered online from the US Geologic Survey. or purchased from dealers such as Blueprints and Copies in Ukiah. With internet access, aerial photographs are available from Google Earth. For a small area such as a parcel, you may purchase a topographic image and aerial photograph by digital download from Topozone for $10. Either may be used as a basemap. The old-fashioned way of adding data is to mark points, lines or boundaries on transparency film, available from any office supply store. This layer, also called an overlay, is placed over the basemap so that it is easy to add or subtract data without repeatedly purchasing or printing the basemap. Layers are useful in tracking changes over time - this is how progress towards the land management goals will be assessed. Other layers that may be useful include a parcel map showing the property boundaries. These can be obtained online from ParcelQuest or photocopied from paper maps at the County Assessors office.
With a large operation, greater efficency may be achieved with a high-tech mapping system, which requires computer software and digital data.
Software
  • Simple mapping tasks can be performed with image processing software. You may already have an image processing program, such as Adobe Photoshop on your computer. If not, there are many free options, such as GIMP.
  • Opensource mapping software, such as QuantumGIS, or Geographical Information System (GIS), such as GRASS, are available for free.
  • Student versions of ArcGIS and IDRISI Andes can be obtained for a few hundred dollars if you qualify as a student in a GIS course.
  • Professional versions of ESRI's ArcGIS, IDRIS's Andes and Cartalinx or other GIS software costs a thousand dollars or more, depending on the package.
Digital Data
  1. Digital map layers for roads, rivers and elevation can be obtained freely from CaSIL.
  2. Digital information particular to your management plan can be generated in the office with GIS software using the technique of "heads-up" digitizing, where a point, line or shape is identified manually using a basemap.
  3. Inexpensive GPS receivers can generate points, lines and shapes in the field.
Inaccuracies in data, including GIS layers, GPS readings or purchased maps, must always be evaluated. Inexpensive or free aerial photos from the USGS archvies may be out-of-date. Features may be missing or mislabelled in data layers from Casil. The solution is to validate against "ground truth" when it is feasible to do so.
The mapping needs of a long-term vegetation management plan can be met within a small budget.

Exercises

  1. Using a computer with internet access, explore the hyperlinks given in the narrative above. Use the interactive maps on the USGS, Google Earth, Topozone and/or ParcelQuest websites to view topographic maps, aerial photos and parcel maps of your site. Download the images and/or data if possible. In Google Earth, add reference points to the image to georeference it for orienting overlays. Do these sources provide basemaps of sufficient quality for your needs?
  2. Open a basemap image in image processing software, such as GIMP, and practice adding points and other features. For example, if the aerial photo is out-of-date and does not include new buildings, those can be added with paint tools. Can you overlay a parcel map on your aerial photo?
  3. Download GIS layers from CaSIL and open them with QGIS. Explore the features of GIS, including finding coordinates and distance measurements.

References

 
The content of the page was last modified 2007-09-13