Continuous Improvements

​​The increasing need for accurate information on agricultural land conversion, expressed by users in government and the private sector, drives the Farmland Mapping and Monitoring Program (FMMP) to continually improve technology and procedures.

The improvements, conducted over several updates, make the paper and digital (GIS) versions of the Important Farmland Maps significantly more accurate and useful. They represent evolutions in technology that have occurred in recent years, and are necessary to create products meeting modern standards for use in the planning process.

2016 - 2018 Update Cycle​:

Survey Area Additions: 

The Important Farmland survey area expanded in three counties for the 2016-2018 map update. Nearly 519,000 acres in Calaveras County, and over 307,000 acres in Tuolumne County were mapped for the first time, filling a longstanding gap in the Sierra foothill counties. Calaveras County adopted a Farmland of Local Importance definition and Tuolumne County did not.

In Los Angeles County, the survey area expanded 710,235 acres into the Los Angeles Basin and Ports of Los Angeles and Long Beach, the majority as Urban and Built-Up Land.  Combined, these three survey area additions bring over 1.5 million acres into the program, for a total survey area of 50.6 million acres in 51 counties.

Improved County Boundary Data:

The 2016-2018 Important Farmland data adopted the California Department of Forestry and Fire Protection's Fire and Resource Assessment Program (FRAP) 2018 version of California Counties GIS data.  This version has a vastly improved coastline with more detailed mapping of piers, jetties, breakwaters, coastal rocks, and sea stacks.  Some of these features result in very small polygons, many less than an acre. ​

2014 - 2016 Update Cycle​: Advances in technology have improved the program’s accuracy, efficiency, and accessibility of data. Most recently, FMMP incorporated the new USDA-NRCS gridded soil survey product into our workflow and modified our protocols to no longer merge sub-acre soil polygons in our data for increased workflow efficiency. 

2012 - 2014 Update Cycle​: Each update cycle provides the opportunity to make improvements to the Important Farmland data, in order to achieve increased accuracy, process efficiency or better reporting capabilities.  Beginning with the 2014 update, FMMP GIS data is released in the North American Datum of 1983 (NAD83) which is the State of California standard datum for GIS data.  The Important Farmland GIS data had historically been released in the North American Datum of 1927 (NAD27).  The North American Datum of 1983 allows for more accuracy since NAD83 corrects some of the distortions from NAD27 over distance by using a set of positions from terrestrial and Doppler satellite data.  Also, keeping up with the latest GIS data delivery and display, a web map time series was created with every update year of FMMP data to provide a long-term perspective on land use conversion in a given area.​