What the data for this category looks like
Data for this category comes from the national land spatial planning unified map, project approval and supervision platform, land use status database, and ecological protection redline data. Update frequency is irregular. Daily processed documents include land use preliminary examination and site selection opinions, construction land planning permits, construction engineering planning permits, redline drawings, and planning conditions. Each document includes fields such as project number, site selection scope, land use scale, and control requirements. Some documents have attachments linked to spatial coordinates. A single project typically corresponds to multiple related documents of different types.
What constraints these characteristics impose on vector models and indexing
Multi-source heterogeneous data from different supervision platforms has inconsistent metadata formats after parsing. Indexing must support flexible project-level association to enable cross-document ledger aggregation. Irregular update frequency requires indexing to support incremental synchronization mechanisms, avoiding resource consumption from full reconstruction. Documents contain spatial control text and a small number of spatial attachments. Vectorization models must accurately capture core semantics such as land use redlines and control requirements. A single project corresponds to multiple documents of different types. Indexing must support aggregation and recall by project ID, preventing scattered retrieval results that reduce ledger summary efficiency. The maxToken value must be adjusted based on the number of documents linked to a single project, adapting to context splicing requirements for projects of different scales.
How to set configurations
| Configuration Item | Recommended Value | Rationale |
|---|---|---|
| Chunk Length | 800–1200 characters | Adapts to the typical paragraph length of planning conditions and permit opinions, avoiding semantic fragmentation |
| Overlap Length | 100–150 characters | Covers control requirement statements across chunks, preventing semantic breaks |
| Similarity Threshold | 0.72–0.78, calibrated via actual testing | Balances precise matching and recall coverage, adapting to the semantic similarity distribution of land control-related text |
| Single Search Limit | Top 10 results | Controls redundancy of returned results, focusing on core control clauses and related documents |
| maxToken | 8000 | Adapts to context splicing for multiple permit documents, complying with input limits of general large models |
| defaultToken | 200 | Controls the output length of a single vector, optimizing index storage efficiency |
Three common errors
- No options appear in the interface index model dropdown box: Clicking the dropdown box displays no available model list. The cause is incorrect configuration of the local embedding model access path, or failure to load the corresponding model plugin in the system.
- Redline drawing-related control clauses are missing from ledger summary results: The generated report does not include spatial control requirements corresponding to redline drawings. The cause is excessively small chunk length, which splits redline drawing spatial descriptions into meaningless fragments, causing semantic loss after vectorization.
- Index generation fails when calling One API to forward embedding models: Vectorization tasks throw errors with no valid return content. The cause is incorrect specification of the embedding model name in the configuration, or lack of call permissions for the corresponding model in the forwarding service.
How to confirm correct configuration
- Upload a single land use preliminary examination opinion document. Check that the vectorization task status in FastGPT v4.17.0 shows success, and that generated vector dimensions match the selected model's standard.
- Search for the keyword "ecological protection redline". Verify that the number of returned results matches the number of actual related documents, then adjust the similarity threshold to a range that meets business needs.
- Batch import 10 recent project documents. Check that incremental indexing synchronizes automatically, with no full reconstruction task triggered.
- Call the ledger summary interface. Check that the returned report includes all related planning permits and redline drawing-related content, with no missing fields.
The values listed above are common starting points and should be evaluated against the reader's own samples.
Question material comes from public community discussions. Configuration values are common starting points and should be measured against your own samples. Verified on 2026-09-28.